Add Path and OsString APIs

7 files changed, 5754 insertions, 4 deletions

diff --git a/src/ascii.rs b/src/ascii.rs
new file mode 100644
index 0000000..93f447b
--- /dev/null
+++ b/src/ascii.rs
@@ -0,0 +1,554 @@
+// Copyright 2013-2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! Operations on ASCII strings and characters.
+
+use core::mem;
+use core::ops::Range;
+use collections::{String, Vec};
+
+/// Extension methods for ASCII-subset only operations on string slices.
+///
+/// Be aware that operations on seemingly non-ASCII characters can sometimes
+/// have unexpected results. Consider this example:
+///
+/// ```
+/// use std::ascii::AsciiExt;
+///
+/// assert_eq!("café".to_ascii_uppercase(), "CAFÉ");
+/// assert_eq!("café".to_ascii_uppercase(), "CAFé");
+/// ```
+///
+/// In the first example, the lowercased string is represented `"cafe\u{301}"`
+/// (the last character is an acute accent [combining character]). Unlike the
+/// other characters in the string, the combining character will not get mapped
+/// to an uppercase variant, resulting in `"CAFE\u{301}"`. In the second
+/// example, the lowercased string is represented `"caf\u{e9}"` (the last
+/// character is a single Unicode character representing an 'e' with an acute
+/// accent). Since the last character is defined outside the scope of ASCII,
+/// it will not get mapped to an uppercase variant, resulting in `"CAF\u{e9}"`.
+///
+/// [combining character]: https://en.wikipedia.org/wiki/Combining_character
+pub trait AsciiExt {
+    /// Container type for copied ASCII characters.
+    type Owned;
+
+    /// Checks if the value is within the ASCII range.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::ascii::AsciiExt;
+    ///
+    /// let ascii = 'a';
+    /// let utf8 = '❤';
+    ///
+    /// assert!(ascii.is_ascii());
+    /// assert!(!utf8.is_ascii());
+    /// ```
+    fn is_ascii(&self) -> bool;
+
+    /// Makes a copy of the string in ASCII upper case.
+    ///
+    /// ASCII letters 'a' to 'z' are mapped to 'A' to 'Z',
+    /// but non-ASCII letters are unchanged.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::ascii::AsciiExt;
+    ///
+    /// let ascii = 'a';
+    /// let utf8 = '❤';
+    ///
+    /// assert_eq!('A', ascii.to_ascii_uppercase());
+    /// assert_eq!('❤', utf8.to_ascii_uppercase());
+    /// ```
+    fn to_ascii_uppercase(&self) -> Self::Owned;
+
+    /// Makes a copy of the string in ASCII lower case.
+    ///
+    /// ASCII letters 'A' to 'Z' are mapped to 'a' to 'z',
+    /// but non-ASCII letters are unchanged.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::ascii::AsciiExt;
+    ///
+    /// let ascii = 'A';
+    /// let utf8 = '❤';
+    ///
+    /// assert_eq!('a', ascii.to_ascii_lowercase());
+    /// assert_eq!('❤', utf8.to_ascii_lowercase());
+    /// ```
+    fn to_ascii_lowercase(&self) -> Self::Owned;
+
+    /// Checks that two strings are an ASCII case-insensitive match.
+    ///
+    /// Same as `to_ascii_lowercase(a) == to_ascii_lowercase(b)`,
+    /// but without allocating and copying temporary strings.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::ascii::AsciiExt;
+    ///
+    /// let ascii1 = 'A';
+    /// let ascii2 = 'a';
+    /// let ascii3 = 'A';
+    /// let ascii4 = 'z';
+    ///
+    /// assert!(ascii1.eq_ignore_ascii_case(&ascii2));
+    /// assert!(ascii1.eq_ignore_ascii_case(&ascii3));
+    /// assert!(!ascii1.eq_ignore_ascii_case(&ascii4));
+    /// ```
+    fn eq_ignore_ascii_case(&self, other: &Self) -> bool;
+
+    /// Converts this type to its ASCII upper case equivalent in-place.
+    ///
+    /// See `to_ascii_uppercase` for more information.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::ascii::AsciiExt;
+    ///
+    /// let mut ascii = 'a';
+    ///
+    /// ascii.make_ascii_uppercase();
+    ///
+    /// assert_eq!('A', ascii);
+    /// ```
+    fn make_ascii_uppercase(&mut self);
+
+    /// Converts this type to its ASCII lower case equivalent in-place.
+    ///
+    /// See `to_ascii_lowercase` for more information.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::ascii::AsciiExt;
+    ///
+    /// let mut ascii = 'A';
+    ///
+    /// ascii.make_ascii_lowercase();
+    ///
+    /// assert_eq!('a', ascii);
+    /// ```
+    fn make_ascii_lowercase(&mut self);
+}
+
+impl AsciiExt for str {
+    type Owned = String;
+
+    #[inline]
+    fn is_ascii(&self) -> bool {
+        self.bytes().all(|b| b.is_ascii())
+    }
+
+    #[inline]
+    fn to_ascii_uppercase(&self) -> String {
+        let mut bytes = self.as_bytes().to_vec();
+        bytes.make_ascii_uppercase();
+        // make_ascii_uppercase() preserves the UTF-8 invariant.
+        unsafe { String::from_utf8_unchecked(bytes) }
+    }
+
+    #[inline]
+    fn to_ascii_lowercase(&self) -> String {
+        let mut bytes = self.as_bytes().to_vec();
+        bytes.make_ascii_lowercase();
+        // make_ascii_uppercase() preserves the UTF-8 invariant.
+        unsafe { String::from_utf8_unchecked(bytes) }
+    }
+
+    #[inline]
+    fn eq_ignore_ascii_case(&self, other: &str) -> bool {
+        self.as_bytes().eq_ignore_ascii_case(other.as_bytes())
+    }
+
+    fn make_ascii_uppercase(&mut self) {
+        let me: &mut [u8] = unsafe { mem::transmute(self) };
+        me.make_ascii_uppercase()
+    }
+
+    fn make_ascii_lowercase(&mut self) {
+        let me: &mut [u8] = unsafe { mem::transmute(self) };
+        me.make_ascii_lowercase()
+    }
+}
+
+impl AsciiExt for [u8] {
+    type Owned = Vec<u8>;
+    #[inline]
+    fn is_ascii(&self) -> bool {
+        self.iter().all(|b| b.is_ascii())
+    }
+
+    #[inline]
+    fn to_ascii_uppercase(&self) -> Vec<u8> {
+        let mut me = self.to_vec();
+        me.make_ascii_uppercase();
+        return me
+    }
+
+    #[inline]
+    fn to_ascii_lowercase(&self) -> Vec<u8> {
+        let mut me = self.to_vec();
+        me.make_ascii_lowercase();
+        return me
+    }
+
+    #[inline]
+    fn eq_ignore_ascii_case(&self, other: &[u8]) -> bool {
+        self.len() == other.len() &&
+        self.iter().zip(other).all(|(a, b)| {
+            a.eq_ignore_ascii_case(b)
+        })
+    }
+
+    fn make_ascii_uppercase(&mut self) {
+        for byte in self {
+            byte.make_ascii_uppercase();
+        }
+    }
+
+    fn make_ascii_lowercase(&mut self) {
+        for byte in self {
+            byte.make_ascii_lowercase();
+        }
+    }
+}
+
+impl AsciiExt for u8 {
+    type Owned = u8;
+    #[inline]
+    fn is_ascii(&self) -> bool { *self & 128 == 0 }
+    #[inline]
+    fn to_ascii_uppercase(&self) -> u8 { ASCII_UPPERCASE_MAP[*self as usize] }
+    #[inline]
+    fn to_ascii_lowercase(&self) -> u8 { ASCII_LOWERCASE_MAP[*self as usize] }
+    #[inline]
+    fn eq_ignore_ascii_case(&self, other: &u8) -> bool {
+        self.to_ascii_lowercase() == other.to_ascii_lowercase()
+    }
+    #[inline]
+    fn make_ascii_uppercase(&mut self) { *self = self.to_ascii_uppercase(); }
+    #[inline]
+    fn make_ascii_lowercase(&mut self) { *self = self.to_ascii_lowercase(); }
+}
+
+impl AsciiExt for char {
+    type Owned = char;
+    #[inline]
+    fn is_ascii(&self) -> bool {
+        *self as u32 <= 0x7F
+    }
+
+    #[inline]
+    fn to_ascii_uppercase(&self) -> char {
+        if self.is_ascii() {
+            (*self as u8).to_ascii_uppercase() as char
+        } else {
+            *self
+        }
+    }
+
+    #[inline]
+    fn to_ascii_lowercase(&self) -> char {
+        if self.is_ascii() {
+            (*self as u8).to_ascii_lowercase() as char
+        } else {
+            *self
+        }
+    }
+
+    #[inline]
+    fn eq_ignore_ascii_case(&self, other: &char) -> bool {
+        self.to_ascii_lowercase() == other.to_ascii_lowercase()
+    }
+
+    #[inline]
+    fn make_ascii_uppercase(&mut self) { *self = self.to_ascii_uppercase(); }
+    #[inline]
+    fn make_ascii_lowercase(&mut self) { *self = self.to_ascii_lowercase(); }
+}
+
+/// An iterator over the escaped version of a byte, constructed via
+/// `std::ascii::escape_default`.
+pub struct EscapeDefault {
+    range: Range<usize>,
+    data: [u8; 4],
+}
+
+/// Returns an iterator that produces an escaped version of a `u8`.
+///
+/// The default is chosen with a bias toward producing literals that are
+/// legal in a variety of languages, including C++11 and similar C-family
+/// languages. The exact rules are:
+///
+/// - Tab, CR and LF are escaped as '\t', '\r' and '\n' respectively.
+/// - Single-quote, double-quote and backslash chars are backslash-escaped.
+/// - Any other chars in the range [0x20,0x7e] are not escaped.
+/// - Any other chars are given hex escapes of the form '\xNN'.
+/// - Unicode escapes are never generated by this function.
+///
+/// # Examples
+///
+/// ```
+/// use std::ascii;
+///
+/// let escaped = ascii::escape_default(b'0').next().unwrap();
+/// assert_eq!(b'0', escaped);
+///
+/// let mut escaped = ascii::escape_default(b'\t');
+///
+/// assert_eq!(b'\\', escaped.next().unwrap());
+/// assert_eq!(b't', escaped.next().unwrap());
+/// ```
+pub fn escape_default(c: u8) -> EscapeDefault {
+    let (data, len) = match c {
+        b'\t' => ([b'\\', b't', 0, 0], 2),
+        b'\r' => ([b'\\', b'r', 0, 0], 2),
+        b'\n' => ([b'\\', b'n', 0, 0], 2),
+        b'\\' => ([b'\\', b'\\', 0, 0], 2),
+        b'\'' => ([b'\\', b'\'', 0, 0], 2),
+        b'"' => ([b'\\', b'"', 0, 0], 2),
+        b'\x20' ... b'\x7e' => ([c, 0, 0, 0], 1),
+        _ => ([b'\\', b'x', hexify(c >> 4), hexify(c & 0xf)], 4),
+    };
+
+    return EscapeDefault { range: (0.. len), data: data };
+
+    fn hexify(b: u8) -> u8 {
+        match b {
+            0 ... 9 => b'0' + b,
+            _ => b'a' + b - 10,
+        }
+    }
+}
+
+impl Iterator for EscapeDefault {
+    type Item = u8;
+    fn next(&mut self) -> Option<u8> { self.range.next().map(|i| self.data[i]) }
+    fn size_hint(&self) -> (usize, Option<usize>) { self.range.size_hint() }
+}
+impl DoubleEndedIterator for EscapeDefault {
+    fn next_back(&mut self) -> Option<u8> {
+        self.range.next_back().map(|i| self.data[i])
+    }
+}
+impl ExactSizeIterator for EscapeDefault {}
+
+static ASCII_LOWERCASE_MAP: [u8; 256] = [
+    0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
+    0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
+    0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
+    0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
+    b' ', b'!', b'"', b'#', b'$', b'%', b'&', b'\'',
+    b'(', b')', b'*', b'+', b',', b'-', b'.', b'/',
+    b'0', b'1', b'2', b'3', b'4', b'5', b'6', b'7',
+    b'8', b'9', b':', b';', b'<', b'=', b'>', b'?',
+    b'@',
+
+          b'a', b'b', b'c', b'd', b'e', b'f', b'g',
+    b'h', b'i', b'j', b'k', b'l', b'm', b'n', b'o',
+    b'p', b'q', b'r', b's', b't', b'u', b'v', b'w',
+    b'x', b'y', b'z',
+
+                      b'[', b'\\', b']', b'^', b'_',
+    b'`', b'a', b'b', b'c', b'd', b'e', b'f', b'g',
+    b'h', b'i', b'j', b'k', b'l', b'm', b'n', b'o',
+    b'p', b'q', b'r', b's', b't', b'u', b'v', b'w',
+    b'x', b'y', b'z', b'{', b'|', b'}', b'~', 0x7f,
+    0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87,
+    0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f,
+    0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97,
+    0x98, 0x99, 0x9a, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f,
+    0xa0, 0xa1, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7,
+    0xa8, 0xa9, 0xaa, 0xab, 0xac, 0xad, 0xae, 0xaf,
+    0xb0, 0xb1, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6, 0xb7,
+    0xb8, 0xb9, 0xba, 0xbb, 0xbc, 0xbd, 0xbe, 0xbf,
+    0xc0, 0xc1, 0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc7,
+    0xc8, 0xc9, 0xca, 0xcb, 0xcc, 0xcd, 0xce, 0xcf,
+    0xd0, 0xd1, 0xd2, 0xd3, 0xd4, 0xd5, 0xd6, 0xd7,
+    0xd8, 0xd9, 0xda, 0xdb, 0xdc, 0xdd, 0xde, 0xdf,
+    0xe0, 0xe1, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7,
+    0xe8, 0xe9, 0xea, 0xeb, 0xec, 0xed, 0xee, 0xef,
+    0xf0, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7,
+    0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xff,
+];
+
+static ASCII_UPPERCASE_MAP: [u8; 256] = [
+    0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
+    0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
+    0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
+    0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
+    b' ', b'!', b'"', b'#', b'$', b'%', b'&', b'\'',
+    b'(', b')', b'*', b'+', b',', b'-', b'.', b'/',
+    b'0', b'1', b'2', b'3', b'4', b'5', b'6', b'7',
+    b'8', b'9', b':', b';', b'<', b'=', b'>', b'?',
+    b'@', b'A', b'B', b'C', b'D', b'E', b'F', b'G',
+    b'H', b'I', b'J', b'K', b'L', b'M', b'N', b'O',
+    b'P', b'Q', b'R', b'S', b'T', b'U', b'V', b'W',
+    b'X', b'Y', b'Z', b'[', b'\\', b']', b'^', b'_',
+    b'`',
+
+          b'A', b'B', b'C', b'D', b'E', b'F', b'G',
+    b'H', b'I', b'J', b'K', b'L', b'M', b'N', b'O',
+    b'P', b'Q', b'R', b'S', b'T', b'U', b'V', b'W',
+    b'X', b'Y', b'Z',
+
+                      b'{', b'|', b'}', b'~', 0x7f,
+    0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87,
+    0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f,
+    0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97,
+    0x98, 0x99, 0x9a, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f,
+    0xa0, 0xa1, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7,
+    0xa8, 0xa9, 0xaa, 0xab, 0xac, 0xad, 0xae, 0xaf,
+    0xb0, 0xb1, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6, 0xb7,
+    0xb8, 0xb9, 0xba, 0xbb, 0xbc, 0xbd, 0xbe, 0xbf,
+    0xc0, 0xc1, 0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc7,
+    0xc8, 0xc9, 0xca, 0xcb, 0xcc, 0xcd, 0xce, 0xcf,
+    0xd0, 0xd1, 0xd2, 0xd3, 0xd4, 0xd5, 0xd6, 0xd7,
+    0xd8, 0xd9, 0xda, 0xdb, 0xdc, 0xdd, 0xde, 0xdf,
+    0xe0, 0xe1, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7,
+    0xe8, 0xe9, 0xea, 0xeb, 0xec, 0xed, 0xee, 0xef,
+    0xf0, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7,
+    0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xff,
+];
+
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use rustc_unicode::char::from_u32;
+    use collections::string::ToString;
+
+    #[test]
+    fn test_is_ascii() {
+        assert!(b"".is_ascii());
+        assert!(b"banana\0\x7F".is_ascii());
+        assert!(b"banana\0\x7F".iter().all(|b| b.is_ascii()));
+        assert!(!b"Vi\xe1\xbb\x87t Nam".is_ascii());
+        assert!(!b"Vi\xe1\xbb\x87t Nam".iter().all(|b| b.is_ascii()));
+        assert!(!b"\xe1\xbb\x87".iter().any(|b| b.is_ascii()));
+
+        assert!("".is_ascii());
+        assert!("banana\0\u{7F}".is_ascii());
+        assert!("banana\0\u{7F}".chars().all(|c| c.is_ascii()));
+        assert!(!"ประเทศไทย中华Việt Nam".chars().all(|c| c.is_ascii()));
+
+        // NOTE: This test fails for some reason.
+        assert!(!"ประเทศไทย中华ệ ".chars().any(|c| c.is_ascii()));
+    }
+
+    #[test]
+    fn test_to_ascii_uppercase() {
+        assert_eq!("url()URL()uRl()ürl".to_ascii_uppercase(), "URL()URL()URL()üRL");
+        assert_eq!("hıKß".to_ascii_uppercase(), "HıKß");
+
+        for i in 0..501 {
+            let upper = if 'a' as u32 <= i && i <= 'z' as u32 { i + 'A' as u32 - 'a' as u32 }
+                        else { i };
+            assert_eq!((from_u32(i).unwrap()).to_string().to_ascii_uppercase(),
+                       (from_u32(upper).unwrap()).to_string());
+        }
+    }
+
+    #[test]
+    fn test_to_ascii_lowercase() {
+        assert_eq!("url()URL()uRl()Ürl".to_ascii_lowercase(), "url()url()url()Ürl");
+        // Dotted capital I, Kelvin sign, Sharp S.
+        assert_eq!("HİKß".to_ascii_lowercase(), "hİKß");
+
+        for i in 0..501 {
+            let lower = if 'A' as u32 <= i && i <= 'Z' as u32 { i + 'a' as u32 - 'A' as u32 }
+                        else { i };
+            assert_eq!((from_u32(i).unwrap()).to_string().to_ascii_lowercase(),
+                       (from_u32(lower).unwrap()).to_string());
+        }
+    }
+
+    #[test]
+    fn test_make_ascii_lower_case() {
+        macro_rules! test {
+            ($from: expr, $to: expr) => {
+                {
+                    let mut x = $from;
+                    x.make_ascii_lowercase();
+                    assert_eq!(x, $to);
+                }
+            }
+        }
+        test!(b'A', b'a');
+        test!(b'a', b'a');
+        test!(b'!', b'!');
+        test!('A', 'a');
+        test!('À', 'À');
+        test!('a', 'a');
+        test!('!', '!');
+        test!(b"H\xc3\x89".to_vec(), b"h\xc3\x89");
+        test!("HİKß".to_string(), "hİKß");
+    }
+
+
+    #[test]
+    fn test_make_ascii_upper_case() {
+        macro_rules! test {
+            ($from: expr, $to: expr) => {
+                {
+                    let mut x = $from;
+                    x.make_ascii_uppercase();
+                    assert_eq!(x, $to);
+                }
+            }
+        }
+        test!(b'a', b'A');
+        test!(b'A', b'A');
+        test!(b'!', b'!');
+        test!('a', 'A');
+        test!('à', 'à');
+        test!('A', 'A');
+        test!('!', '!');
+        test!(b"h\xc3\xa9".to_vec(), b"H\xc3\xa9");
+        test!("hıKß".to_string(), "HıKß");
+
+        let mut x = "Hello".to_string();
+        x[..3].make_ascii_uppercase();  // Test IndexMut on String.
+        assert_eq!(x, "HELlo")
+    }
+
+    #[test]
+    fn test_eq_ignore_ascii_case() {
+        assert!("url()URL()uRl()Ürl".eq_ignore_ascii_case("url()url()url()Ürl"));
+        assert!(!"Ürl".eq_ignore_ascii_case("ürl"));
+        // Dotted capital I, Kelvin sign, Sharp S.
+        assert!("HİKß".eq_ignore_ascii_case("hİKß"));
+        assert!(!"İ".eq_ignore_ascii_case("i"));
+        assert!(!"K".eq_ignore_ascii_case("k"));
+        assert!(!"ß".eq_ignore_ascii_case("s"));
+
+        for i in 0..501 {
+            let lower = if 'A' as u32 <= i && i <= 'Z' as u32 { i + 'a' as u32 - 'A' as u32 }
+                        else { i };
+            assert!((from_u32(i).unwrap()).to_string().eq_ignore_ascii_case(
+                    &from_u32(lower).unwrap().to_string()));
+        }
+    }
+
+    #[test]
+    fn inference_works() {
+        let x = "a".to_string();
+        x.eq_ignore_ascii_case("A");
+    }
+}
diff --git a/src/ffi/mod.rs b/src/ffi/mod.rs
new file mode 100644
index 0000000..3a2d5f1
--- /dev/null
+++ b/src/ffi/mod.rs
@@ -0,0 +1,3 @@
+pub use self::os_str::{OsString, OsStr};
+
+mod os_str;
diff --git a/src/ffi/os_str.rs b/src/ffi/os_str.rs
new file mode 100644
index 0000000..d062d55
--- /dev/null
+++ b/src/ffi/os_str.rs
@@ -0,0 +1,576 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use collections::borrow::{Borrow, Cow, ToOwned};
+use core::fmt::{self, Debug};
+use core::mem;
+use collections::String;
+use core::ops;
+use core::cmp;
+use core::hash::{Hash, Hasher};
+use collections::Vec;
+
+use sys::wtf8::{Wtf8, Wtf8Buf};
+use sys::{AsInner, IntoInner, FromInner};
+
+pub use sys::wtf8::EncodeWide;
+
+/// A type that can represent owned, mutable platform-native strings, but is
+/// cheaply inter-convertible with Rust strings.
+///
+/// The need for this type arises from the fact that:
+///
+/// * On Unix systems, strings are often arbitrary sequences of non-zero
+///   bytes, in many cases interpreted as UTF-8.
+///
+/// * On Windows, strings are often arbitrary sequences of non-zero 16-bit
+///   values, interpreted as UTF-16 when it is valid to do so.
+///
+/// * In Rust, strings are always valid UTF-8, but may contain zeros.
+///
+/// `OsString` and `OsStr` bridge this gap by simultaneously representing Rust
+/// and platform-native string values, and in particular allowing a Rust string
+/// to be converted into an "OS" string with no cost.
+#[derive(Clone)]
+pub struct OsString {
+    inner: Wtf8Buf 
+}
+
+/// Slices into OS strings (see `OsString`).
+pub struct OsStr {
+    inner: Wtf8
+}
+
+impl OsString {
+    /// Constructs a new empty `OsString`.
+    pub fn new() -> OsString {
+        OsString { inner: Wtf8Buf::from_string(String::new()) }
+    }
+
+    fn _from_bytes(vec: Vec<u8>) -> Option<OsString> {
+        String::from_utf8(vec).ok().map(OsString::from)
+    }
+
+    /// Converts to an `OsStr` slice.
+    pub fn as_os_str(&self) -> &OsStr {
+        self
+    }
+
+    /// Converts the `OsString` into a `String` if it contains valid Unicode data.
+    ///
+    /// On failure, ownership of the original `OsString` is returned.
+    pub fn into_string(self) -> Result<String, OsString> {
+        self.inner.into_string().map_err(|buf| OsString { inner: buf} )
+    }
+
+    /// Extends the string with the given `&OsStr` slice.
+    pub fn push<T: AsRef<OsStr>>(&mut self, s: T) {
+        self.inner.push_wtf8(&s.as_ref().inner)
+    }
+
+    /// Creates a new `OsString` with the given capacity.
+    ///
+    /// The string will be able to hold exactly `capacity` lenth units of other
+    /// OS strings without reallocating. If `capacity` is 0, the string will not
+    /// allocate.
+    ///
+    /// See main `OsString` documentation information about encoding.
+    pub fn with_capacity(capacity: usize) -> OsString {
+        OsString {
+            inner: Wtf8Buf::with_capacity(capacity)
+        }
+    }
+
+    /// Truncates the `OsString` to zero length.
+    pub fn clear(&mut self) {
+        self.inner.clear()
+    }
+
+    /// Returns the capacity this `OsString` can hold without reallocating.
+    ///
+    /// See `OsString` introduction for information about encoding.
+    pub fn capacity(&self) -> usize {
+        self.inner.capacity()
+    }
+
+    /// Reserves capacity for at least `additional` more capacity to be inserted
+    /// in the given `OsString`.
+    ///
+    /// The collection may reserve more space to avoid frequent reallocations.
+    pub fn reserve(&mut self, additional: usize) {
+        self.inner.reserve(additional)
+    }
+
+    /// Reserves the minimum capacity for exactly `additional` more capacity to
+    /// be inserted in the given `OsString`. Does nothing if the capacity is
+    /// already sufficient.
+    ///
+    /// Note that the allocator may give the collection more space than it
+    /// requests. Therefore capacity can not be relied upon to be precisely
+    /// minimal. Prefer reserve if future insertions are expected.
+    pub fn reserve_exact(&mut self, additional: usize) {
+        self.inner.reserve_exact(additional)
+    }
+
+    /// Creates an `OsString` from a potentially ill-formed UTF-16 slice of
+    /// 16-bit code units.
+    ///
+    /// This is lossless: calling `.encode_wide()` on the resulting string
+    /// will always return the original code units.
+    ///
+    /// NOTE: This function was copied from the windows implementation of OsStringExt
+    pub fn from_wide(wide: &[u16]) -> OsString {
+        OsString { inner: Wtf8Buf::from_wide(wide) }
+    }
+}
+
+impl From<String> for OsString {
+    fn from(s: String) -> OsString {
+        OsString { inner: Wtf8Buf::from_string(s) }
+    }
+}
+
+impl<'a, T: ?Sized + AsRef<OsStr>> From<&'a T> for OsString {
+    fn from(s: &'a T) -> OsString {
+        s.as_ref().to_os_string()
+    }
+}
+
+impl ops::Index<ops::RangeFull> for OsString {
+    type Output = OsStr;
+
+    #[inline]
+    fn index(&self, _index: ops::RangeFull) -> &OsStr {
+        OsStr::from_inner(self.inner.as_slice())
+    }
+}
+
+impl ops::Deref for OsString {
+    type Target = OsStr;
+
+    #[inline]
+    fn deref(&self) -> &OsStr {
+        &self[..]
+    }
+}
+
+impl Default for OsString {
+    #[inline]
+    fn default() -> OsString {
+        OsString::new()
+    }
+}
+
+impl Debug for OsString {
+    fn fmt(&self, formatter: &mut fmt::Formatter) -> Result<(), fmt::Error> {
+        fmt::Debug::fmt(&**self, formatter)
+    }
+}
+
+impl PartialEq for OsString {
+    fn eq(&self, other: &OsString) -> bool {
+        &**self == &**other
+    }
+}
+
+impl PartialEq<str> for OsString {
+    fn eq(&self, other: &str) -> bool {
+        &**self == other
+    }
+}
+
+impl PartialEq<OsString> for str {
+    fn eq(&self, other: &OsString) -> bool {
+        &**other == self
+    }
+}
+
+impl Eq for OsString {}
+
+impl PartialOrd for OsString {
+    #[inline]
+    fn partial_cmp(&self, other: &OsString) -> Option<cmp::Ordering> {
+        (&**self).partial_cmp(&**other)
+    }
+    #[inline]
+    fn lt(&self, other: &OsString) -> bool { &**self < &**other }
+    #[inline]
+    fn le(&self, other: &OsString) -> bool { &**self <= &**other }
+    #[inline]
+    fn gt(&self, other: &OsString) -> bool { &**self > &**other }
+    #[inline]
+    fn ge(&self, other: &OsString) -> bool { &**self >= &**other }
+}
+
+impl PartialOrd<str> for OsString {
+    #[inline]
+    fn partial_cmp(&self, other: &str) -> Option<cmp::Ordering> {
+        (&**self).partial_cmp(other)
+    }
+}
+
+impl Ord for OsString {
+    #[inline]
+    fn cmp(&self, other: &OsString) -> cmp::Ordering {
+        (&**self).cmp(&**other)
+    }
+}
+
+impl Hash for OsString {
+    #[inline]
+    fn hash<H: Hasher>(&self, state: &mut H) {
+        (&**self).hash(state)
+    }
+}
+
+impl OsStr {
+    /// Coerces into an `OsStr` slice.
+    pub fn new<S: AsRef<OsStr> + ?Sized>(s: &S) -> &OsStr {
+        s.as_ref()
+    }
+
+    fn from_inner(inner: &Wtf8) -> &OsStr {
+        unsafe { mem::transmute(inner) }
+    }
+
+    /// Yields a `&str` slice if the `OsStr` is valid Unicode.
+    ///
+    /// This conversion may entail doing a check for UTF-8 validity.
+    pub fn to_str(&self) -> Option<&str> {
+        self.inner.as_str()
+    }
+
+    /// Converts an `OsStr` to a `Cow<str>`.
+    ///
+    /// Any non-Unicode sequences are replaced with U+FFFD REPLACEMENT CHARACTER.
+    pub fn to_string_lossy(&self) -> Cow<str> {
+        self.inner.to_string_lossy()
+    }
+
+    /// Copies the slice into an owned `OsString`.
+    pub fn to_os_string(&self) -> OsString {
+        let mut buf = Wtf8Buf::with_capacity(self.inner.len());
+        buf.push_wtf8(&self.inner);
+        OsString { inner: buf }
+    }
+
+    /// Checks whether the `OsStr` is empty.
+    pub fn is_empty(&self) -> bool {
+        self.inner.is_empty()
+    }
+
+    /// Returns the length of this `OsStr`.
+    ///
+    /// Note that this does **not** return the number of bytes in this string
+    /// as, for example, OS strings on Windows are encoded as a list of `u16`
+    /// rather than a list of bytes. This number is simply useful for passing to
+    /// other methods like `OsString::with_capacity` to avoid reallocations.
+    ///
+    /// See `OsStr` introduction for more information about encoding.
+    pub fn len(&self) -> usize {
+        self.inner.len()
+    }
+
+    /// Gets the underlying byte representation.
+    ///
+    /// Note: it is *crucial* that this API is private, to avoid
+    /// revealing the internal, platform-specific encodings.
+    fn bytes(&self) -> &[u8] {
+        unsafe { mem::transmute(&self.inner) }
+    }
+    
+    /// Re-encodes an `OsStr` as a wide character sequence,
+    /// i.e. potentially ill-formed UTF-16.
+    /// This is lossless. Note that the encoding does not include a final
+    /// null.
+    ///
+    /// NOTE: This function was copied from the windows implementation of OsStrExt
+    pub fn encode_wide(&self) -> EncodeWide {
+        self.inner.encode_wide()
+    }
+
+}
+
+impl<'a> Default for &'a OsStr {
+    #[inline]
+    fn default() -> &'a OsStr {
+        OsStr::new("")
+    }
+}
+
+impl PartialEq for OsStr {
+    fn eq(&self, other: &OsStr) -> bool {
+        self.bytes().eq(other.bytes())
+    }
+}
+
+impl PartialEq<str> for OsStr {
+    fn eq(&self, other: &str) -> bool {
+        *self == *OsStr::new(other)
+    }
+}
+
+impl PartialEq<OsStr> for str {
+    fn eq(&self, other: &OsStr) -> bool {
+        *other == *OsStr::new(self)
+    }
+}
+
+impl Eq for OsStr {}
+
+impl PartialOrd for OsStr {
+    #[inline]
+    fn partial_cmp(&self, other: &OsStr) -> Option<cmp::Ordering> {
+        self.bytes().partial_cmp(other.bytes())
+    }
+    #[inline]
+    fn lt(&self, other: &OsStr) -> bool { self.bytes().lt(other.bytes()) }
+    #[inline]
+    fn le(&self, other: &OsStr) -> bool { self.bytes().le(other.bytes()) }
+    #[inline]
+    fn gt(&self, other: &OsStr) -> bool { self.bytes().gt(other.bytes()) }
+    #[inline]
+    fn ge(&self, other: &OsStr) -> bool { self.bytes().ge(other.bytes()) }
+}
+
+impl PartialOrd<str> for OsStr {
+    #[inline]
+    fn partial_cmp(&self, other: &str) -> Option<cmp::Ordering> {
+        self.partial_cmp(OsStr::new(other))
+    }
+}
+
+// FIXME (#19470): cannot provide PartialOrd<OsStr> for str until we
+// have more flexible coherence rules.
+
+impl Ord for OsStr {
+    #[inline]
+    fn cmp(&self, other: &OsStr) -> cmp::Ordering { self.bytes().cmp(other.bytes()) }
+}
+
+macro_rules! impl_cmp {
+    ($lhs:ty, $rhs: ty) => {
+        impl<'a, 'b> PartialEq<$rhs> for $lhs {
+            #[inline]
+            fn eq(&self, other: &$rhs) -> bool { <OsStr as PartialEq>::eq(self, other) }
+        }
+
+        impl<'a, 'b> PartialEq<$lhs> for $rhs {
+            #[inline]
+            fn eq(&self, other: &$lhs) -> bool { <OsStr as PartialEq>::eq(self, other) }
+        }
+
+        impl<'a, 'b> PartialOrd<$rhs> for $lhs {
+            #[inline]
+            fn partial_cmp(&self, other: &$rhs) -> Option<cmp::Ordering> {
+                <OsStr as PartialOrd>::partial_cmp(self, other)
+            }
+        }
+
+        impl<'a, 'b> PartialOrd<$lhs> for $rhs {
+            #[inline]
+            fn partial_cmp(&self, other: &$lhs) -> Option<cmp::Ordering> {
+                <OsStr as PartialOrd>::partial_cmp(self, other)
+            }
+        }
+    }
+}
+
+impl_cmp!(OsString, OsStr);
+impl_cmp!(OsString, &'a OsStr);
+impl_cmp!(Cow<'a, OsStr>, OsStr);
+impl_cmp!(Cow<'a, OsStr>, &'b OsStr);
+impl_cmp!(Cow<'a, OsStr>, OsString);
+
+impl Hash for OsStr {
+    #[inline]
+    fn hash<H: Hasher>(&self, state: &mut H) {
+        self.bytes().hash(state)
+    }
+}
+
+impl Debug for OsStr {
+    fn fmt(&self, formatter: &mut fmt::Formatter) -> Result<(), fmt::Error> {
+        self.inner.fmt(formatter)
+    }
+}
+
+impl Borrow<OsStr> for OsString {
+    fn borrow(&self) -> &OsStr { &self[..] }
+}
+
+impl ToOwned for OsStr {
+    type Owned = OsString;
+    fn to_owned(&self) -> OsString { self.to_os_string() }
+}
+
+impl AsRef<OsStr> for OsStr {
+    fn as_ref(&self) -> &OsStr {
+        self
+    }
+}
+
+impl AsRef<OsStr> for OsString {
+    fn as_ref(&self) -> &OsStr {
+        self
+    }
+}
+
+impl AsRef<OsStr> for str {
+    fn as_ref(&self) -> &OsStr {
+        OsStr::from_inner(Wtf8::from_str(self))
+    }
+}
+
+impl AsRef<OsStr> for String {
+    fn as_ref(&self) -> &OsStr {
+        (&**self).as_ref()
+    }
+}
+
+impl FromInner<Wtf8Buf> for OsString {
+    fn from_inner(buf: Wtf8Buf) -> OsString {
+        OsString { inner: buf }
+    }
+}
+
+impl IntoInner<Wtf8Buf> for OsString {
+    fn into_inner(self) -> Wtf8Buf {
+        self.inner
+    }
+}
+
+impl AsInner<Wtf8> for OsStr {
+    fn as_inner(&self) -> &Wtf8 {
+        &self.inner
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use sys::{AsInner, IntoInner};
+
+    #[test]
+    fn test_os_string_with_capacity() {
+        let os_string = OsString::with_capacity(0);
+        assert_eq!(0, os_string.inner.capacity());
+
+        let os_string = OsString::with_capacity(10);
+        assert_eq!(10, os_string.inner.capacity());
+
+        let mut os_string = OsString::with_capacity(0);
+        os_string.push("abc");
+        assert!(os_string.inner.capacity() >= 3);
+    }
+
+    #[test]
+    fn test_os_string_clear() {
+        let mut os_string = OsString::from("abc");
+        assert_eq!(3, os_string.inner.len());
+
+        os_string.clear();
+        assert_eq!(&os_string, "");
+        assert_eq!(0, os_string.inner.len());
+    }
+
+    #[test]
+    fn test_os_string_capacity() {
+        let os_string = OsString::with_capacity(0);
+        assert_eq!(0, os_string.capacity());
+
+        let os_string = OsString::with_capacity(10);
+        assert_eq!(10, os_string.capacity());
+
+        let mut os_string = OsString::with_capacity(0);
+        os_string.push("abc");
+        assert!(os_string.capacity() >= 3);
+    }
+
+    #[test]
+    fn test_os_string_reserve() {
+        let mut os_string = OsString::new();
+        assert_eq!(os_string.capacity(), 0);
+
+        os_string.reserve(2);
+        assert!(os_string.capacity() >= 2);
+
+        for _ in 0..16 {
+            os_string.push("a");
+        }
+
+        assert!(os_string.capacity() >= 16);
+        os_string.reserve(16);
+        assert!(os_string.capacity() >= 32);
+
+        os_string.push("a");
+
+        os_string.reserve(16);
+        assert!(os_string.capacity() >= 33)
+    }
+
+    #[test]
+    fn test_os_string_reserve_exact() {
+        let mut os_string = OsString::new();
+        assert_eq!(os_string.capacity(), 0);
+
+        os_string.reserve_exact(2);
+        assert!(os_string.capacity() >= 2);
+
+        for _ in 0..16 {
+            os_string.push("a");
+        }
+
+        assert!(os_string.capacity() >= 16);
+        os_string.reserve_exact(16);
+        assert!(os_string.capacity() >= 32);
+
+        os_string.push("a");
+
+        os_string.reserve_exact(16);
+        assert!(os_string.capacity() >= 33)
+    }
+
+    #[test]
+    fn test_os_string_default() {
+        let os_string: OsString = Default::default();
+        assert_eq!("", &os_string);
+    }
+
+    #[test]
+    fn test_os_str_is_empty() {
+        let mut os_string = OsString::new();
+        assert!(os_string.is_empty());
+
+        os_string.push("abc");
+        assert!(!os_string.is_empty());
+
+        os_string.clear();
+        assert!(os_string.is_empty());
+    }
+
+    #[test]
+    fn test_os_str_len() {
+        let mut os_string = OsString::new();
+        assert_eq!(0, os_string.len());
+
+        os_string.push("abc");
+        assert_eq!(3, os_string.len());
+
+        os_string.clear();
+        assert_eq!(0, os_string.len());
+    }
+
+    #[test]
+    fn test_os_str_default() {
+        let os_str: &OsStr = Default::default();
+        assert_eq!("", os_str);
+    }
+}
diff --git a/src/lib.rs b/src/lib.rs
index dc225c6..7fa8597 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,20 +1,35 @@
-#![feature(alloc, collections, lang_items)]
+#![feature(alloc)]
+#![feature(collections)]
+#![feature(char_escape_debug)]
+#![feature(lang_items)]
+#![feature(question_mark)]
+#![feature(slice_patterns)]
+#![feature(str_internals)]
+#![feature(unicode)]
+
 #![no_std]
+
 #![crate_type = "rlib"]
 #![crate_name = "ctru"]
 
-extern crate ctru_sys as libctru;
-
 extern crate alloc;
 extern crate collections;
+extern crate rustc_unicode;
+
+extern crate ctru_sys as libctru;
 
 pub mod console;
 pub mod srv;
 pub mod gfx;
+pub mod services;
 pub mod sdmc;
 
-pub mod services;
+pub mod ascii;
+pub mod ffi;
 pub mod panic;
+pub mod path;
+
+mod sys;
 
 pub use srv::Srv;
 pub use gfx::Gfx;
diff --git a/src/path.rs b/src/path.rs
new file mode 100644
index 0000000..3fb6357
--- /dev/null
+++ b/src/path.rs
@@ -0,0 +1,3378 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! Cross-platform path manipulation.
+//!
+//! This module provides two types, `PathBuf` and `Path` (akin to `String` and
+//! `str`), for working with paths abstractly. These types are thin wrappers
+//! around `OsString` and `OsStr` respectively, meaning that they work directly
+//! on strings according to the local platform's path syntax.
+//!
+//! ## Simple usage
+//!
+//! Path manipulation includes both parsing components from slices and building
+//! new owned paths.
+//!
+//! To parse a path, you can create a `Path` slice from a `str`
+//! slice and start asking questions:
+//!
+//! ```rust
+//! use std::path::Path;
+//!
+//! let path = Path::new("/tmp/foo/bar.txt");
+//! let file = path.file_name();
+//! let extension = path.extension();
+//! let parent_dir = path.parent();
+//! ```
+//!
+//! To build or modify paths, use `PathBuf`:
+//!
+//! ```rust
+//! use std::path::PathBuf;
+//!
+//! let mut path = PathBuf::from("c:\\");
+//! path.push("windows");
+//! path.push("system32");
+//! path.set_extension("dll");
+//! ```
+//!
+//! ## Path components and normalization
+//!
+//! The path APIs are built around the notion of "components", which roughly
+//! correspond to the substrings between path separators (`/` and, on Windows,
+//! `\`). The APIs for path parsing are largely specified in terms of the path's
+//! components, so it's important to clearly understand how those are
+//! determined.
+//!
+//! A path can always be reconstructed into an *equivalent* path by
+//! putting together its components via `push`. Syntactically, the
+//! paths may differ by the normalization described below.
+//!
+//! ### Component types
+//!
+//! Components come in several types:
+//!
+//! * Normal components are the default: standard references to files or
+//! directories. The path `a/b` has two normal components, `a` and `b`.
+//!
+//! * Current directory components represent the `.` character. For example,
+//! `./a` has a current directory component and a normal component `a`.
+//!
+//! * The root directory component represents a separator that designates
+//!   starting from root. For example, `/a/b` has a root directory component
+//!   followed by normal components `a` and `b`.
+//!
+//! On Windows, an additional component type comes into play:
+//!
+//! * Prefix components, of which there is a large variety. For example, `C:`
+//! and `\\server\share` are prefixes. The path `C:windows` has a prefix
+//! component `C:` and a normal component `windows`; the path `C:\windows` has a
+//! prefix component `C:`, a root directory component, and a normal component
+//! `windows`.
+//!
+//! ### Normalization
+//!
+//! Aside from splitting on the separator(s), there is a small amount of
+//! "normalization":
+//!
+//! * Repeated separators are ignored: `a/b` and `a//b` both have components `a`
+//!   and `b`.
+//!
+//! * Occurrences of `.` are normalized away, *except* if they are at
+//! the beginning of the path (in which case they are often meaningful
+//! in terms of path searching). So, for example, `a/./b`, `a/b/`,
+//! `/a/b/.` and `a/b` all have components `a` and `b`, but `./a/b`
+//! has a leading current directory component.
+//!
+//! No other normalization takes place by default. In particular,
+//! `a/c` and `a/b/../c` are distinct, to account for the possibility
+//! that `b` is a symbolic link (so its parent isn't `a`). Further
+//! normalization is possible to build on top of the components APIs,
+//! and will be included in this library in the near future.
+
+use ascii::*;
+use collections::borrow::{Borrow, ToOwned, Cow};
+use core::cmp;
+//use error::Error;
+use core::fmt;
+//use fs;
+use core::hash::{Hash, Hasher};
+//use io;
+use core::iter;
+use core::mem;
+use core::ops::{self, Deref};
+use collections::String;
+use collections::Vec;
+
+use ffi::{OsStr, OsString};
+
+use self::platform::{is_sep_byte, is_verbatim_sep, MAIN_SEP_STR, parse_prefix};
+
+////////////////////////////////////////////////////////////////////////////////
+// GENERAL NOTES
+////////////////////////////////////////////////////////////////////////////////
+//
+// Parsing in this module is done by directly transmuting OsStr to [u8] slices,
+// taking advantage of the fact that OsStr always encodes ASCII characters
+// as-is.  Eventually, this transmutation should be replaced by direct uses of
+// OsStr APIs for parsing, but it will take a while for those to become
+// available.
+
+////////////////////////////////////////////////////////////////////////////////
+// Platform-specific definitions
+////////////////////////////////////////////////////////////////////////////////
+
+// The following modules give the most basic tools for parsing paths on various
+// platforms. The bulk of the code is devoted to parsing prefixes on Windows.
+
+#[cfg(unix)]
+mod platform {
+    use super::Prefix;
+    use ffi::OsStr;
+
+    #[inline]
+    pub fn is_sep_byte(b: u8) -> bool {
+        b == b'/'
+    }
+
+    #[inline]
+    pub fn is_verbatim_sep(b: u8) -> bool {
+        b == b'/'
+    }
+
+    pub fn parse_prefix(_: &OsStr) -> Option<Prefix> {
+        None
+    }
+
+    pub const MAIN_SEP_STR: &'static str = "/";
+    pub const MAIN_SEP: char = '/';
+}
+
+#[cfg(windows)]
+mod platform {
+    use ascii::*;
+
+    use super::{os_str_as_u8_slice, u8_slice_as_os_str, Prefix};
+    use ffi::OsStr;
+
+    #[inline]
+    pub fn is_sep_byte(b: u8) -> bool {
+        b == b'/' || b == b'\\'
+    }
+
+    #[inline]
+    pub fn is_verbatim_sep(b: u8) -> bool {
+        b == b'\\'
+    }
+
+    pub fn parse_prefix<'a>(path: &'a OsStr) -> Option<Prefix> {
+        use super::Prefix::*;
+        unsafe {
+            // The unsafety here stems from converting between &OsStr and &[u8]
+            // and back. This is safe to do because (1) we only look at ASCII
+            // contents of the encoding and (2) new &OsStr values are produced
+            // only from ASCII-bounded slices of existing &OsStr values.
+            let mut path = os_str_as_u8_slice(path);
+
+            if path.starts_with(br"\\") {
+                // \\
+                path = &path[2..];
+                if path.starts_with(br"?\") {
+                    // \\?\
+                    path = &path[2..];
+                    if path.starts_with(br"UNC\") {
+                        // \\?\UNC\server\share
+                        path = &path[4..];
+                        let (server, share) = match parse_two_comps(path, is_verbatim_sep) {
+                            Some((server, share)) =>
+                                (u8_slice_as_os_str(server), u8_slice_as_os_str(share)),
+                            None => (u8_slice_as_os_str(path), u8_slice_as_os_str(&[])),
+                        };
+                        return Some(VerbatimUNC(server, share));
+                    } else {
+                        // \\?\path
+                        let idx = path.iter().position(|&b| b == b'\\');
+                        if idx == Some(2) && path[1] == b':' {
+                            let c = path[0];
+                            if c.is_ascii() && (c as char).is_alphabetic() {
+                                // \\?\C:\ path
+                                return Some(VerbatimDisk(c.to_ascii_uppercase()));
+                            }
+                        }
+                        let slice = &path[..idx.unwrap_or(path.len())];
+                        return Some(Verbatim(u8_slice_as_os_str(slice)));
+                    }
+                } else if path.starts_with(b".\\") {
+                    // \\.\path
+                    path = &path[2..];
+                    let pos = path.iter().position(|&b| b == b'\\');
+                    let slice = &path[..pos.unwrap_or(path.len())];
+                    return Some(DeviceNS(u8_slice_as_os_str(slice)));
+                }
+                match parse_two_comps(path, is_sep_byte) {
+                    Some((server, share)) if !server.is_empty() && !share.is_empty() => {
+                        // \\server\share
+                        return Some(UNC(u8_slice_as_os_str(server), u8_slice_as_os_str(share)));
+                    }
+                    _ => (),
+                }
+            } else if path.get(1) == Some(& b':') {
+                // C:
+                let c = path[0];
+                if c.is_ascii() && (c as char).is_alphabetic() {
+                    return Some(Disk(c.to_ascii_uppercase()));
+                }
+            }
+            return None;
+        }
+
+        fn parse_two_comps(mut path: &[u8], f: fn(u8) -> bool) -> Option<(&[u8], &[u8])> {
+            let first = match path.iter().position(|x| f(*x)) {
+                None => return None,
+                Some(x) => &path[..x],
+            };
+            path = &path[(first.len() + 1)..];
+            let idx = path.iter().position(|x| f(*x));
+            let second = &path[..idx.unwrap_or(path.len())];
+            Some((first, second))
+        }
+    }
+
+    pub const MAIN_SEP_STR: &'static str = "\\";
+    pub const MAIN_SEP: char = '\\';
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Windows Prefixes
+////////////////////////////////////////////////////////////////////////////////
+
+/// Path prefixes (Windows only).
+///
+/// Windows uses a variety of path styles, including references to drive
+/// volumes (like `C:`), network shared folders (like `\\server\share`) and
+/// others. In addition, some path prefixes are "verbatim", in which case
+/// `/` is *not* treated as a separator and essentially no normalization is
+/// performed.
+#[derive(Copy, Clone, Debug, Hash, PartialOrd, Ord, PartialEq, Eq)]
+pub enum Prefix<'a> {
+    /// Prefix `\\?\`, together with the given component immediately following it.
+    Verbatim(&'a OsStr),
+    /// Prefix `\\?\UNC\`, with the "server" and "share" components following it.
+    VerbatimUNC(
+        &'a OsStr,
+        &'a OsStr,
+    ),
+
+    /// Prefix like `\\?\C:\`, for the given drive letter
+    VerbatimDisk(u8),
+
+    /// Prefix `\\.\`, together with the given component immediately following it.
+    DeviceNS(&'a OsStr),
+
+    /// Prefix `\\server\share`, with the given "server" and "share" components.
+    UNC(
+        &'a OsStr,
+        &'a OsStr,
+    ),
+
+    /// Prefix `C:` for the given disk drive.
+    Disk(u8),
+}
+
+impl<'a> Prefix<'a> {
+    #[inline]
+    fn len(&self) -> usize {
+        use self::Prefix::*;
+        fn os_str_len(s: &OsStr) -> usize {
+            os_str_as_u8_slice(s).len()
+        }
+        match *self {
+            Verbatim(x) => 4 + os_str_len(x),
+            VerbatimUNC(x, y) => {
+                8 + os_str_len(x) +
+                if os_str_len(y) > 0 {
+                    1 + os_str_len(y)
+                } else {
+                    0
+                }
+            },
+            VerbatimDisk(_) => 6,
+            UNC(x, y) => {
+                2 + os_str_len(x) +
+                if os_str_len(y) > 0 {
+                    1 + os_str_len(y)
+                } else {
+                    0
+                }
+            },
+            DeviceNS(x) => 4 + os_str_len(x),
+            Disk(_) => 2,
+        }
+
+    }
+
+    /// Determines if the prefix is verbatim, i.e. begins with `\\?\`.
+    #[inline]
+    pub fn is_verbatim(&self) -> bool {
+        use self::Prefix::*;
+        match *self {
+            Verbatim(_) | VerbatimDisk(_) | VerbatimUNC(_, _) => true,
+            _ => false,
+        }
+    }
+
+    #[inline]
+    fn is_drive(&self) -> bool {
+        match *self {
+            Prefix::Disk(_) => true,
+            _ => false,
+        }
+    }
+
+    #[inline]
+    fn has_implicit_root(&self) -> bool {
+        !self.is_drive()
+    }
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Exposed parsing helpers
+////////////////////////////////////////////////////////////////////////////////
+
+/// Determines whether the character is one of the permitted path
+/// separators for the current platform.
+///
+/// # Examples
+///
+/// ```
+/// use std::path;
+///
+/// assert!(path::is_separator('/'));
+/// assert!(!path::is_separator('❤'));
+/// ```
+pub fn is_separator(c: char) -> bool {
+    c.is_ascii() && is_sep_byte(c as u8)
+}
+
+/// The primary separator for the current platform
+pub const MAIN_SEPARATOR: char = platform::MAIN_SEP;
+
+////////////////////////////////////////////////////////////////////////////////
+// Misc helpers
+////////////////////////////////////////////////////////////////////////////////
+
+// Iterate through `iter` while it matches `prefix`; return `None` if `prefix`
+// is not a prefix of `iter`, otherwise return `Some(iter_after_prefix)` giving
+// `iter` after having exhausted `prefix`.
+fn iter_after<A, I, J>(mut iter: I, mut prefix: J) -> Option<I>
+    where I: Iterator<Item = A> + Clone,
+          J: Iterator<Item = A>,
+          A: PartialEq
+{
+    loop {
+        let mut iter_next = iter.clone();
+        match (iter_next.next(), prefix.next()) {
+            (Some(ref x), Some(ref y)) if x == y => (),
+            (Some(_), Some(_)) => return None,
+            (Some(_), None) => return Some(iter),
+            (None, None) => return Some(iter),
+            (None, Some(_)) => return None,
+        }
+        iter = iter_next;
+    }
+}
+
+// See note at the top of this module to understand why these are used:
+fn os_str_as_u8_slice(s: &OsStr) -> &[u8] {
+    unsafe { mem::transmute(s) }
+}
+unsafe fn u8_slice_as_os_str(s: &[u8]) -> &OsStr {
+    mem::transmute(s)
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Cross-platform, iterator-independent parsing
+////////////////////////////////////////////////////////////////////////////////
+
+/// Says whether the first byte after the prefix is a separator.
+fn has_physical_root(s: &[u8], prefix: Option<Prefix>) -> bool {
+    let path = if let Some(p) = prefix {
+        &s[p.len()..]
+    } else {
+        s
+    };
+    !path.is_empty() && is_sep_byte(path[0])
+}
+
+// basic workhorse for splitting stem and extension
+fn split_file_at_dot(file: &OsStr) -> (Option<&OsStr>, Option<&OsStr>) {
+    unsafe {
+        if os_str_as_u8_slice(file) == b".." {
+            return (Some(file), None);
+        }
+
+        // The unsafety here stems from converting between &OsStr and &[u8]
+        // and back. This is safe to do because (1) we only look at ASCII
+        // contents of the encoding and (2) new &OsStr values are produced
+        // only from ASCII-bounded slices of existing &OsStr values.
+
+        let mut iter = os_str_as_u8_slice(file).rsplitn(2, |b| *b == b'.');
+        let after = iter.next();
+        let before = iter.next();
+        if before == Some(b"") {
+            (Some(file), None)
+        } else {
+            (before.map(|s| u8_slice_as_os_str(s)),
+             after.map(|s| u8_slice_as_os_str(s)))
+        }
+    }
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// The core iterators
+////////////////////////////////////////////////////////////////////////////////
+
+/// Component parsing works by a double-ended state machine; the cursors at the
+/// front and back of the path each keep track of what parts of the path have
+/// been consumed so far.
+///
+/// Going front to back, a path is made up of a prefix, a starting
+/// directory component, and a body (of normal components)
+#[derive(Copy, Clone, PartialEq, PartialOrd, Debug)]
+enum State {
+    Prefix = 0,         // c:
+    StartDir = 1,       // / or . or nothing
+    Body = 2,           // foo/bar/baz
+    Done = 3,
+}
+
+/// A Windows path prefix, e.g. `C:` or `\\server\share`.
+///
+/// Does not occur on Unix.
+#[derive(Copy, Clone, Eq, Debug)]
+pub struct PrefixComponent<'a> {
+    /// The prefix as an unparsed `OsStr` slice.
+    raw: &'a OsStr,
+
+    /// The parsed prefix data.
+    parsed: Prefix<'a>,
+}
+
+impl<'a> PrefixComponent<'a> {
+    /// The parsed prefix data.
+    pub fn kind(&self) -> Prefix<'a> {
+        self.parsed
+    }
+
+    /// The raw `OsStr` slice for this prefix.
+    pub fn as_os_str(&self) -> &'a OsStr {
+        self.raw
+    }
+}
+
+impl<'a> cmp::PartialEq for PrefixComponent<'a> {
+    fn eq(&self, other: &PrefixComponent<'a>) -> bool {
+        cmp::PartialEq::eq(&self.parsed, &other.parsed)
+    }
+}
+
+impl<'a> cmp::PartialOrd for PrefixComponent<'a> {
+    fn partial_cmp(&self, other: &PrefixComponent<'a>) -> Option<cmp::Ordering> {
+        cmp::PartialOrd::partial_cmp(&self.parsed, &other.parsed)
+    }
+}
+
+impl<'a> cmp::Ord for PrefixComponent<'a> {
+    fn cmp(&self, other: &PrefixComponent<'a>) -> cmp::Ordering {
+        cmp::Ord::cmp(&self.parsed, &other.parsed)
+    }
+}
+
+impl<'a> Hash for PrefixComponent<'a> {
+    fn hash<H: Hasher>(&self, h: &mut H) {
+        self.parsed.hash(h);
+    }
+}
+
+/// A single component of a path.
+///
+/// See the module documentation for an in-depth explanation of components and
+/// their role in the API.
+///
+/// This `enum` is created from iterating over the [`path::Components`]
+/// `struct`.
+///
+/// # Examples
+///
+/// ```rust
+/// use std::path::{Component, Path};
+///
+/// let path = Path::new("/tmp/foo/bar.txt");
+/// let components = path.components().collect::<Vec<_>>();
+/// assert_eq!(&components, &[
+///     Component::RootDir,
+///     Component::Normal("tmp".as_ref()),
+///     Component::Normal("foo".as_ref()),
+///     Component::Normal("bar.txt".as_ref()),
+/// ]);
+/// ```
+///
+/// [`path::Components`]: struct.Components.html
+#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
+pub enum Component<'a> {
+    /// A Windows path prefix, e.g. `C:` or `\\server\share`.
+    ///
+    /// Does not occur on Unix.
+    Prefix(
+        PrefixComponent<'a>
+    ),
+
+    /// The root directory component, appears after any prefix and before anything else
+    RootDir,
+
+    /// A reference to the current directory, i.e. `.`
+    CurDir,
+
+    /// A reference to the parent directory, i.e. `..`
+    ParentDir,
+
+    /// A normal component, i.e. `a` and `b` in `a/b`
+    Normal(&'a OsStr),
+}
+
+impl<'a> Component<'a> {
+    /// Extracts the underlying `OsStr` slice
+    pub fn as_os_str(self) -> &'a OsStr {
+        match self {
+            Component::Prefix(p) => p.as_os_str(),
+            Component::RootDir => OsStr::new(MAIN_SEP_STR),
+            Component::CurDir => OsStr::new("."),
+            Component::ParentDir => OsStr::new(".."),
+            Component::Normal(path) => path,
+        }
+    }
+}
+
+impl<'a> AsRef<OsStr> for Component<'a> {
+    fn as_ref(&self) -> &OsStr {
+        self.as_os_str()
+    }
+}
+
+/// The core iterator giving the components of a path.
+///
+/// See the module documentation for an in-depth explanation of components and
+/// their role in the API.
+///
+/// This `struct` is created by the [`path::Path::components`] method.
+///
+/// # Examples
+///
+/// ```
+/// use std::path::Path;
+///
+/// let path = Path::new("/tmp/foo/bar.txt");
+///
+/// for component in path.components() {
+///     println!("{:?}", component);
+/// }
+/// ```
+///
+/// [`path::Path::components`]: struct.Path.html#method.components
+#[derive(Clone)]
+pub struct Components<'a> {
+    // The path left to parse components from
+    path: &'a [u8],
+
+    // The prefix as it was originally parsed, if any
+    prefix: Option<Prefix<'a>>,
+
+    // true if path *physically* has a root separator; for most Windows
+    // prefixes, it may have a "logical" rootseparator for the purposes of
+    // normalization, e.g.  \\server\share == \\server\share\.
+    has_physical_root: bool,
+
+    // The iterator is double-ended, and these two states keep track of what has
+    // been produced from either end
+    front: State,
+    back: State,
+}
+
+/// An iterator over the components of a path, as `OsStr` slices.
+#[derive(Clone)]
+pub struct Iter<'a> {
+    inner: Components<'a>,
+}
+
+impl<'a> Components<'a> {
+    // how long is the prefix, if any?
+    #[inline]
+    fn prefix_len(&self) -> usize {
+        self.prefix.as_ref().map(Prefix::len).unwrap_or(0)
+    }
+
+    #[inline]
+    fn prefix_verbatim(&self) -> bool {
+        self.prefix.as_ref().map(Prefix::is_verbatim).unwrap_or(false)
+    }
+
+    /// how much of the prefix is left from the point of view of iteration?
+    #[inline]
+    fn prefix_remaining(&self) -> usize {
+        if self.front == State::Prefix {
+            self.prefix_len()
+        } else {
+            0
+        }
+    }
+
+    // Given the iteration so far, how much of the pre-State::Body path is left?
+    #[inline]
+    fn len_before_body(&self) -> usize {
+        let root = if self.front <= State::StartDir && self.has_physical_root {
+            1
+        } else {
+            0
+        };
+        let cur_dir = if self.front <= State::StartDir && self.include_cur_dir() {
+            1
+        } else {
+            0
+        };
+        self.prefix_remaining() + root + cur_dir
+    }
+
+    // is the iteration complete?
+    #[inline]
+    fn finished(&self) -> bool {
+        self.front == State::Done || self.back == State::Done || self.front > self.back
+    }
+
+    #[inline]
+    fn is_sep_byte(&self, b: u8) -> bool {
+        if self.prefix_verbatim() {
+            is_verbatim_sep(b)
+        } else {
+            is_sep_byte(b)
+        }
+    }
+
+    /// Extracts a slice corresponding to the portion of the path remaining for iteration.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::path::Path;
+    ///
+    /// let mut components = Path::new("/tmp/foo/bar.txt").components();
+    /// components.next();
+    /// components.next();
+    ///
+    /// assert_eq!(Path::new("foo/bar.txt"), components.as_path());
+    /// ```
+    pub fn as_path(&self) -> &'a Path {
+        let mut comps = self.clone();
+        if comps.front == State::Body {
+            comps.trim_left();
+        }
+        if comps.back == State::Body {
+            comps.trim_right();
+        }
+        unsafe { Path::from_u8_slice(comps.path) }
+    }
+
+    /// Is the *original* path rooted?
+    fn has_root(&self) -> bool {
+        if self.has_physical_root {
+            return true;
+        }
+        if let Some(p) = self.prefix {
+            if p.has_implicit_root() {
+                return true;
+            }
+        }
+        false
+    }
+
+    /// Should the normalized path include a leading . ?
+    fn include_cur_dir(&self) -> bool {
+        if self.has_root() {
+            return false;
+        }
+        let mut iter = self.path[self.prefix_len()..].iter();
+        match (iter.next(), iter.next()) {
+            (Some(&b'.'), None) => true,
+            (Some(&b'.'), Some(&b)) => self.is_sep_byte(b),
+            _ => false,
+        }
+    }
+
+    // parse a given byte sequence into the corresponding path component
+    fn parse_single_component<'b>(&self, comp: &'b [u8]) -> Option<Component<'b>> {
+        match comp {
+            b"." if self.prefix_verbatim() => Some(Component::CurDir),
+            b"." => None, // . components are normalized away, except at
+                          // the beginning of a path, which is treated
+                          // separately via `include_cur_dir`
+            b".." => Some(Component::ParentDir),
+            b"" => None,
+            _ => Some(Component::Normal(unsafe { u8_slice_as_os_str(comp) })),
+        }
+    }
+
+    // parse a component from the left, saying how many bytes to consume to
+    // remove the component
+    fn parse_next_component(&self) -> (usize, Option<Component<'a>>) {
+        debug_assert!(self.front == State::Body);
+        let (extra, comp) = match self.path.iter().position(|b| self.is_sep_byte(*b)) {
+            None => (0, self.path),
+            Some(i) => (1, &self.path[..i]),
+        };
+        (comp.len() + extra, self.parse_single_component(comp))
+    }
+
+    // parse a component from the right, saying how many bytes to consume to
+    // remove the component
+    fn parse_next_component_back(&self) -> (usize, Option<Component<'a>>) {
+        debug_assert!(self.back == State::Body);
+        let start = self.len_before_body();
+        let (extra, comp) = match self.path[start..].iter().rposition(|b| self.is_sep_byte(*b)) {
+            None => (0, &self.path[start..]),
+            Some(i) => (1, &self.path[start + i + 1..]),
+        };
+        (comp.len() + extra, self.parse_single_component(comp))
+    }
+
+    // trim away repeated separators (i.e. empty components) on the left
+    fn trim_left(&mut self) {
+        while !self.path.is_empty() {
+            let (size, comp) = self.parse_next_component();
+            if comp.is_some() {
+                return;
+            } else {
+                self.path = &self.path[size..];
+            }
+        }
+    }
+
+    // trim away repeated separators (i.e. empty components) on the right
+    fn trim_right(&mut self) {
+        while self.path.len() > self.len_before_body() {
+            let (size, comp) = self.parse_next_component_back();
+            if comp.is_some() {
+                return;
+            } else {
+                self.path = &self.path[..self.path.len() - size];
+            }
+        }
+    }
+}
+
+impl<'a> AsRef<Path> for Components<'a> {
+    fn as_ref(&self) -> &Path {
+        self.as_path()
+    }
+}
+
+impl<'a> AsRef<OsStr> for Components<'a> {
+    fn as_ref(&self) -> &OsStr {
+        self.as_path().as_os_str()
+    }
+}
+
+impl<'a> Iter<'a> {
+    /// Extracts a slice corresponding to the portion of the path remaining for iteration.
+    pub fn as_path(&self) -> &'a Path {
+        self.inner.as_path()
+    }
+}
+
+impl<'a> AsRef<Path> for Iter<'a> {
+    fn as_ref(&self) -> &Path {
+        self.as_path()
+    }
+}
+
+impl<'a> AsRef<OsStr> for Iter<'a> {
+    fn as_ref(&self) -> &OsStr {
+        self.as_path().as_os_str()
+    }
+}
+
+impl<'a> Iterator for Iter<'a> {
+    type Item = &'a OsStr;
+
+    fn next(&mut self) -> Option<&'a OsStr> {
+        self.inner.next().map(Component::as_os_str)
+    }
+}
+
+impl<'a> DoubleEndedIterator for Iter<'a> {
+    fn next_back(&mut self) -> Option<&'a OsStr> {
+        self.inner.next_back().map(Component::as_os_str)
+    }
+}
+
+impl<'a> Iterator for Components<'a> {
+    type Item = Component<'a>;
+
+    fn next(&mut self) -> Option<Component<'a>> {
+        while !self.finished() {
+            match self.front {
+                State::Prefix if self.prefix_len() > 0 => {
+                    self.front = State::StartDir;
+                    debug_assert!(self.prefix_len() <= self.path.len());
+                    let raw = &self.path[..self.prefix_len()];
+                    self.path = &self.path[self.prefix_len()..];
+                    return Some(Component::Prefix(PrefixComponent {
+                        raw: unsafe { u8_slice_as_os_str(raw) },
+                        parsed: self.prefix.unwrap(),
+                    }));
+                }
+                State::Prefix => {
+                    self.front = State::StartDir;
+                }
+                State::StartDir => {
+                    self.front = State::Body;
+                    if self.has_physical_root {
+                        debug_assert!(!self.path.is_empty());
+                        self.path = &self.path[1..];
+                        return Some(Component::RootDir);
+                    } else if let Some(p) = self.prefix {
+                        if p.has_implicit_root() && !p.is_verbatim() {
+                            return Some(Component::RootDir);
+                        }
+                    } else if self.include_cur_dir() {
+                        debug_assert!(!self.path.is_empty());
+                        self.path = &self.path[1..];
+                        return Some(Component::CurDir);
+                    }
+                }
+                State::Body if !self.path.is_empty() => {
+                    let (size, comp) = self.parse_next_component();
+                    self.path = &self.path[size..];
+                    if comp.is_some() {
+                        return comp;
+                    }
+                }
+                State::Body => {
+                    self.front = State::Done;
+                }
+                State::Done => unreachable!(),
+            }
+        }
+        None
+    }
+}
+
+impl<'a> DoubleEndedIterator for Components<'a> {
+    fn next_back(&mut self) -> Option<Component<'a>> {
+        while !self.finished() {
+            match self.back {
+                State::Body if self.path.len() > self.len_before_body() => {
+                    let (size, comp) = self.parse_next_component_back();
+                    self.path = &self.path[..self.path.len() - size];
+                    if comp.is_some() {
+                        return comp;
+                    }
+                }
+                State::Body => {
+                    self.back = State::StartDir;
+                }
+                State::StartDir => {
+                    self.back = State::Prefix;
+                    if self.has_physical_root {
+                        self.path = &self.path[..self.path.len() - 1];
+                        return Some(Component::RootDir);
+                    } else if let Some(p) = self.prefix {
+                        if p.has_implicit_root() && !p.is_verbatim() {
+                            return Some(Component::RootDir);
+                        }
+                    } else if self.include_cur_dir() {
+                        self.path = &self.path[..self.path.len() - 1];
+                        return Some(Component::CurDir);
+                    }
+                }
+                State::Prefix if self.prefix_len() > 0 => {
+                    self.back = State::Done;
+                    return Some(Component::Prefix(PrefixComponent {
+                        raw: unsafe { u8_slice_as_os_str(self.path) },
+                        parsed: self.prefix.unwrap(),
+                    }));
+                }
+                State::Prefix => {
+                    self.back = State::Done;
+                    return None;
+                }
+                State::Done => unreachable!(),
+            }
+        }
+        None
+    }
+}
+
+impl<'a> cmp::PartialEq for Components<'a> {
+    fn eq(&self, other: &Components<'a>) -> bool {
+        Iterator::eq(self.clone(), other.clone())
+    }
+}
+
+impl<'a> cmp::Eq for Components<'a> {}
+
+impl<'a> cmp::PartialOrd for Components<'a> {
+    fn partial_cmp(&self, other: &Components<'a>) -> Option<cmp::Ordering> {
+        Iterator::partial_cmp(self.clone(), other.clone())
+    }
+}
+
+impl<'a> cmp::Ord for Components<'a> {
+    fn cmp(&self, other: &Components<'a>) -> cmp::Ordering {
+        Iterator::cmp(self.clone(), other.clone())
+    }
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Basic types and traits
+////////////////////////////////////////////////////////////////////////////////
+
+/// An owned, mutable path (akin to `String`).
+///
+/// This type provides methods like `push` and `set_extension` that mutate the
+/// path in place. It also implements `Deref` to `Path`, meaning that all
+/// methods on `Path` slices are available on `PathBuf` values as well.
+///
+/// More details about the overall approach can be found in
+/// the module documentation.
+///
+/// # Examples
+///
+/// ```
+/// use std::path::PathBuf;
+///
+/// let mut path = PathBuf::from("c:\\");
+/// path.push("windows");
+/// path.push("system32");
+/// path.set_extension("dll");
+/// ```
+#[derive(Clone)]
+pub struct PathBuf {
+    inner: OsString,
+}
+
+impl PathBuf {
+    fn as_mut_vec(&mut self) -> &mut Vec<u8> {
+        unsafe { &mut *(self as *mut PathBuf as *mut Vec<u8>) }
+    }
+
+    /// Allocates an empty `PathBuf`.
+    pub fn new() -> PathBuf {
+        PathBuf { inner: OsString::new() }
+    }
+
+    /// Coerces to a `Path` slice.
+    pub fn as_path(&self) -> &Path {
+        self
+    }
+
+    /// Extends `self` with `path`.
+    ///
+    /// If `path` is absolute, it replaces the current path.
+    ///
+    /// On Windows:
+    ///
+    /// * if `path` has a root but no prefix (e.g. `\windows`), it
+    ///   replaces everything except for the prefix (if any) of `self`.
+    /// * if `path` has a prefix but no root, it replaces `self`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::path::PathBuf;
+    ///
+    /// let mut path = PathBuf::new();
+    /// path.push("/tmp");
+    /// path.push("file.bk");
+    /// assert_eq!(path, PathBuf::from("/tmp/file.bk"));
+    ///
+    /// // Pushing an absolute path replaces the current path
+    /// path.push("/etc/passwd");
+    /// assert_eq!(path, PathBuf::from("/etc/passwd"));
+    /// ```
+    pub fn push<P: AsRef<Path>>(&mut self, path: P) {
+        self._push(path.as_ref())
+    }
+
+    fn _push(&mut self, path: &Path) {
+        // in general, a separator is needed if the rightmost byte is not a separator
+        let mut need_sep = self.as_mut_vec().last().map(|c| !is_sep_byte(*c)).unwrap_or(false);
+
+        // in the special case of `C:` on Windows, do *not* add a separator
+        {
+            let comps = self.components();
+            if comps.prefix_len() > 0 && comps.prefix_len() == comps.path.len() &&
+               comps.prefix.unwrap().is_drive() {
+                need_sep = false
+            }
+        }
+
+        // absolute `path` replaces `self`
+        if path.is_absolute() || path.prefix().is_some() {
+            self.as_mut_vec().truncate(0);
+
+        // `path` has a root but no prefix, e.g. `\windows` (Windows only)
+        } else if path.has_root() {
+            let prefix_len = self.components().prefix_remaining();
+            self.as_mut_vec().truncate(prefix_len);
+
+        // `path` is a pure relative path
+        } else if need_sep {
+            self.inner.push(MAIN_SEP_STR);
+        }
+
+        self.inner.push(path);
+    }
+
+    /// Truncate `self` to `self.parent()`.
+    ///
+    /// Returns false and does nothing if `self.file_name()` is `None`.
+    /// Otherwise, returns `true`.
+    pub fn pop(&mut self) -> bool {
+        match self.parent().map(|p| p.as_u8_slice().len()) {
+            Some(len) => {
+                self.as_mut_vec().truncate(len);
+                true
+            }
+            None => false,
+        }
+    }
+
+    /// Updates `self.file_name()` to `file_name`.
+    ///
+    /// If `self.file_name()` was `None`, this is equivalent to pushing
+    /// `file_name`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::path::PathBuf;
+    ///
+    /// let mut buf = PathBuf::from("/");
+    /// assert!(buf.file_name() == None);
+    /// buf.set_file_name("bar");
+    /// assert!(buf == PathBuf::from("/bar"));
+    /// assert!(buf.file_name().is_some());
+    /// buf.set_file_name("baz.txt");
+    /// assert!(buf == PathBuf::from("/baz.txt"));
+    /// ```
+    pub fn set_file_name<S: AsRef<OsStr>>(&mut self, file_name: S) {
+        self._set_file_name(file_name.as_ref())
+    }
+
+    fn _set_file_name(&mut self, file_name: &OsStr) {
+        if self.file_name().is_some() {
+            let popped = self.pop();
+            debug_assert!(popped);
+        }
+        self.push(file_name);
+    }
+
+    /// Updates `self.extension()` to `extension`.
+    ///
+    /// If `self.file_name()` is `None`, does nothing and returns `false`.
+    ///
+    /// Otherwise, returns `true`; if `self.extension()` is `None`, the extension
+    /// is added; otherwise it is replaced.
+    pub fn set_extension<S: AsRef<OsStr>>(&mut self, extension: S) -> bool {
+        self._set_extension(extension.as_ref())
+    }
+
+    fn _set_extension(&mut self, extension: &OsStr) -> bool {
+        if self.file_name().is_none() {
+            return false;
+        }
+
+        let mut stem = match self.file_stem() {
+            Some(stem) => stem.to_os_string(),
+            None => OsString::new(),
+        };
+
+        if !os_str_as_u8_slice(extension).is_empty() {
+            stem.push(".");
+            stem.push(extension);
+        }
+        self.set_file_name(&stem);
+
+        true
+    }
+
+    /// Consumes the `PathBuf`, yielding its internal `OsString` storage.
+    pub fn into_os_string(self) -> OsString {
+        self.inner
+    }
+}
+
+impl<'a, T: ?Sized + AsRef<OsStr>> From<&'a T> for PathBuf {
+    fn from(s: &'a T) -> PathBuf {
+        PathBuf::from(s.as_ref().to_os_string())
+    }
+}
+
+impl From<OsString> for PathBuf {
+    fn from(s: OsString) -> PathBuf {
+        PathBuf { inner: s }
+    }
+}
+
+impl From<String> for PathBuf {
+    fn from(s: String) -> PathBuf {
+        PathBuf::from(OsString::from(s))
+    }
+}
+
+impl<P: AsRef<Path>> iter::FromIterator<P> for PathBuf {
+    fn from_iter<I: IntoIterator<Item = P>>(iter: I) -> PathBuf {
+        let mut buf = PathBuf::new();
+        buf.extend(iter);
+        buf
+    }
+}
+
+impl<P: AsRef<Path>> iter::Extend<P> for PathBuf {
+    fn extend<I: IntoIterator<Item = P>>(&mut self, iter: I) {
+        for p in iter {
+            self.push(p.as_ref())
+        }
+    }
+}
+
+impl fmt::Debug for PathBuf {
+    fn fmt(&self, formatter: &mut fmt::Formatter) -> Result<(), fmt::Error> {
+        fmt::Debug::fmt(&**self, formatter)
+    }
+}
+
+impl ops::Deref for PathBuf {
+    type Target = Path;
+
+    fn deref(&self) -> &Path {
+        Path::new(&self.inner)
+    }
+}
+
+impl Borrow<Path> for PathBuf {
+    fn borrow(&self) -> &Path {
+        self.deref()
+    }
+}
+
+impl<'a> From<&'a Path> for Cow<'a, Path> {
+    #[inline]
+    fn from(s: &'a Path) -> Cow<'a, Path> {
+        Cow::Borrowed(s)
+    }
+}
+
+impl<'a> From<PathBuf> for Cow<'a, Path> {
+    #[inline]
+    fn from(s: PathBuf) -> Cow<'a, Path> {
+        Cow::Owned(s)
+    }
+}
+
+impl ToOwned for Path {
+    type Owned = PathBuf;
+    fn to_owned(&self) -> PathBuf {
+        self.to_path_buf()
+    }
+}
+
+impl cmp::PartialEq for PathBuf {
+    fn eq(&self, other: &PathBuf) -> bool {
+        self.components() == other.components()
+    }
+}
+
+impl Hash for PathBuf {
+    fn hash<H: Hasher>(&self, h: &mut H) {
+        self.as_path().hash(h)
+    }
+}
+
+impl cmp::Eq for PathBuf {}
+
+impl cmp::PartialOrd for PathBuf {
+    fn partial_cmp(&self, other: &PathBuf) -> Option<cmp::Ordering> {
+        self.components().partial_cmp(other.components())
+    }
+}
+
+impl cmp::Ord for PathBuf {
+    fn cmp(&self, other: &PathBuf) -> cmp::Ordering {
+        self.components().cmp(other.components())
+    }
+}
+
+impl AsRef<OsStr> for PathBuf {
+    fn as_ref(&self) -> &OsStr {
+        &self.inner[..]
+    }
+}
+
+impl Into<OsString> for PathBuf {
+    fn into(self) -> OsString {
+        self.inner
+    }
+}
+
+/// A slice of a path (akin to `str`).
+///
+/// This type supports a number of operations for inspecting a path, including
+/// breaking the path into its components (separated by `/` or `\`, depending on
+/// the platform), extracting the file name, determining whether the path is
+/// absolute, and so on. More details about the overall approach can be found in
+/// the module documentation.
+///
+/// This is an *unsized* type, meaning that it must always be used behind a
+/// pointer like `&` or `Box`.
+///
+/// # Examples
+///
+/// ```
+/// use std::path::Path;
+///
+/// let path = Path::new("/tmp/foo/bar.txt");
+/// let file = path.file_name();
+/// let extension = path.extension();
+/// let parent_dir = path.parent();
+/// ```
+///
+pub struct Path {
+    inner: OsStr,
+}
+
+/// An error returned from the `Path::strip_prefix` method indicating that the
+/// prefix was not found in `self`.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct StripPrefixError(());
+
+impl Path {
+    // The following (private!) function allows construction of a path from a u8
+    // slice, which is only safe when it is known to follow the OsStr encoding.
+    unsafe fn from_u8_slice(s: &[u8]) -> &Path {
+        Path::new(u8_slice_as_os_str(s))
+    }
+    // The following (private!) function reveals the byte encoding used for OsStr.
+    fn as_u8_slice(&self) -> &[u8] {
+        os_str_as_u8_slice(&self.inner)
+    }
+
+    /// Directly wrap a string slice as a `Path` slice.
+    ///
+    /// This is a cost-free conversion.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::path::Path;
+    ///
+    /// Path::new("foo.txt");
+    /// ```
+    ///
+    /// You can create `Path`s from `String`s, or even other `Path`s:
+    ///
+    /// ```
+    /// use std::path::Path;
+    ///
+    /// let string = String::from("foo.txt");
+    /// let from_string = Path::new(&string);
+    /// let from_path = Path::new(&from_string);
+    /// assert_eq!(from_string, from_path);
+    /// ```
+    pub fn new<S: AsRef<OsStr> + ?Sized>(s: &S) -> &Path {
+        unsafe { mem::transmute(s.as_ref()) }
+    }
+
+    /// Yields the underlying `OsStr` slice.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::path::Path;
+    ///
+    /// let os_str = Path::new("foo.txt").as_os_str();
+    /// assert_eq!(os_str, std::ffi::OsStr::new("foo.txt"));
+    /// ```
+    pub fn as_os_str(&self) -> &OsStr {
+        &self.inner
+    }
+
+    /// Yields a `&str` slice if the `Path` is valid unicode.
+    ///
+    /// This conversion may entail doing a check for UTF-8 validity.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::path::Path;
+    ///
+    /// let path_str = Path::new("foo.txt").to_str();
+    /// assert_eq!(path_str, Some("foo.txt"));
+    /// ```
+    pub fn to_str(&self) -> Option<&str> {
+        self.inner.to_str()
+    }
+
+    /// Converts a `Path` to a `Cow<str>`.
+    ///
+    /// Any non-Unicode sequences are replaced with U+FFFD REPLACEMENT CHARACTER.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::path::Path;
+    ///
+    /// let path_str = Path::new("foo.txt").to_string_lossy();
+    /// assert_eq!(path_str, "foo.txt");
+    /// ```
+    pub fn to_string_lossy(&self) -> Cow<str> {
+        self.inner.to_string_lossy()
+    }
+
+    /// Converts a `Path` to an owned `PathBuf`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::path::Path;
+    ///
+    /// let path_buf = Path::new("foo.txt").to_path_buf();
+    /// assert_eq!(path_buf, std::path::PathBuf::from("foo.txt"));
+    /// ```
+    pub fn to_path_buf(&self) -> PathBuf {
+        PathBuf::from(self.inner.to_os_string())
+    }
+
+    /// A path is *absolute* if it is independent of the current directory.
+    ///
+    /// * On Unix, a path is absolute if it starts with the root, so
+    /// `is_absolute` and `has_root` are equivalent.
+    ///
+    /// * On Windows, a path is absolute if it has a prefix and starts with the
+    /// root: `c:\windows` is absolute, while `c:temp` and `\temp` are not.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::path::Path;
+    ///
+    /// assert!(!Path::new("foo.txt").is_absolute());
+    /// ```
+    #[allow(deprecated)]
+    pub fn is_absolute(&self) -> bool {
+        self.has_root() && (cfg!(unix) || self.prefix().is_some())
+    }
+
+    /// A path is *relative* if it is not absolute.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::path::Path;
+    ///
+    /// assert!(Path::new("foo.txt").is_relative());
+    /// ```
+    pub fn is_relative(&self) -> bool {
+        !self.is_absolute()
+    }
+
+    fn prefix(&self) -> Option<Prefix> {
+        self.components().prefix
+    }
+
+    /// A path has a root if the body of the path begins with the directory separator.
+    ///
+    /// * On Unix, a path has a root if it begins with `/`.
+    ///
+    /// * On Windows, a path has a root if it:
+    ///     * has no prefix and begins with a separator, e.g. `\\windows`
+    ///     * has a prefix followed by a separator, e.g. `c:\windows` but not `c:windows`
+    ///     * has any non-disk prefix, e.g. `\\server\share`
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::path::Path;
+    ///
+    /// assert!(Path::new("/etc/passwd").has_root());
+    /// ```
+    pub fn has_root(&self) -> bool {
+        self.components().has_root()
+    }
+
+    /// The path without its final component, if any.
+    ///
+    /// Returns `None` if the path terminates in a root or prefix.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::path::Path;
+    ///
+    /// let path = Path::new("/foo/bar");
+    /// let parent = path.parent().unwrap();
+    /// assert_eq!(parent, Path::new("/foo"));
+    ///
+    /// let grand_parent = parent.parent().unwrap();
+    /// assert_eq!(grand_parent, Path::new("/"));
+    /// assert_eq!(grand_parent.parent(), None);
+    /// ```
+    pub fn parent(&self) -> Option<&Path> {
+        let mut comps = self.components();
+        let comp = comps.next_back();
+        comp.and_then(|p| {
+            match p {
+                Component::Normal(_) |
+                Component::CurDir |
+                Component::ParentDir => Some(comps.as_path()),
+                _ => None,
+            }
+        })
+    }
+
+    /// The final component of the path, if it is a normal file.
+    ///
+    /// If the path terminates in `..`, `file_name` will return `None`.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::path::Path;
+    /// use std::ffi::OsStr;
+    ///
+    /// let path = Path::new("foo.txt");
+    /// let os_str = OsStr::new("foo.txt");
+    ///
+    /// assert_eq!(Some(os_str), path.file_name());
+    /// ```
+    ///
+    /// # Other examples
+    ///
+    /// ```
+    /// use std::path::Path;
+    /// use std::ffi::OsStr;
+    ///
+    /// assert_eq!(Some(OsStr::new("foo.txt")), Path::new("foo.txt/.").file_name());
+    /// assert_eq!(Some(OsStr::new("foo.txt")), Path::new("foo.txt/.//").file_name());
+    /// assert_eq!(None, Path::new("foo.txt/..").file_name());
+    /// ```
+    pub fn file_name(&self) -> Option<&OsStr> {
+        self.components().next_back().and_then(|p| {
+            match p {
+                Component::Normal(p) => Some(p.as_ref()),
+                _ => None,
+            }
+        })
+    }
+
+    /// Returns a path that, when joined onto `base`, yields `self`.
+    ///
+    /// # Errors
+    ///
+    /// If `base` is not a prefix of `self` (i.e. `starts_with`
+    /// returns `false`), returns `Err`.
+    pub fn strip_prefix<'a, P: ?Sized>(&'a self, base: &'a P)
+                                       -> Result<&'a Path, StripPrefixError>
+        where P: AsRef<Path>
+    {
+        self._strip_prefix(base.as_ref())
+    }
+
+    fn _strip_prefix<'a>(&'a self, base: &'a Path)
+                         -> Result<&'a Path, StripPrefixError> {
+        iter_after(self.components(), base.components())
+            .map(|c| c.as_path())
+            .ok_or(StripPrefixError(()))
+    }
+
+    /// Determines whether `base` is a prefix of `self`.
+    ///
+    /// Only considers whole path components to match.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::path::Path;
+    ///
+    /// let path = Path::new("/etc/passwd");
+    ///
+    /// assert!(path.starts_with("/etc"));
+    ///
+    /// assert!(!path.starts_with("/e"));
+    /// ```
+    pub fn starts_with<P: AsRef<Path>>(&self, base: P) -> bool {
+        self._starts_with(base.as_ref())
+    }
+
+    fn _starts_with(&self, base: &Path) -> bool {
+        iter_after(self.components(), base.components()).is_some()
+    }
+
+    /// Determines whether `child` is a suffix of `self`.
+    ///
+    /// Only considers whole path components to match.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::path::Path;
+    ///
+    /// let path = Path::new("/etc/passwd");
+    ///
+    /// assert!(path.ends_with("passwd"));
+    /// ```
+    pub fn ends_with<P: AsRef<Path>>(&self, child: P) -> bool {
+        self._ends_with(child.as_ref())
+    }
+
+    fn _ends_with(&self, child: &Path) -> bool {
+        iter_after(self.components().rev(), child.components().rev()).is_some()
+    }
+
+    /// Extracts the stem (non-extension) portion of `self.file_name()`.
+    ///
+    /// The stem is:
+    ///
+    /// * None, if there is no file name;
+    /// * The entire file name if there is no embedded `.`;
+    /// * The entire file name if the file name begins with `.` and has no other `.`s within;
+    /// * Otherwise, the portion of the file name before the final `.`
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::path::Path;
+    ///
+    /// let path = Path::new("foo.rs");
+    ///
+    /// assert_eq!("foo", path.file_stem().unwrap());
+    /// ```
+    pub fn file_stem(&self) -> Option<&OsStr> {
+        self.file_name().map(split_file_at_dot).and_then(|(before, after)| before.or(after))
+    }
+
+    /// Extracts the extension of `self.file_name()`, if possible.
+    ///
+    /// The extension is:
+    ///
+    /// * None, if there is no file name;
+    /// * None, if there is no embedded `.`;
+    /// * None, if the file name begins with `.` and has no other `.`s within;
+    /// * Otherwise, the portion of the file name after the final `.`
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::path::Path;
+    ///
+    /// let path = Path::new("foo.rs");
+    ///
+    /// assert_eq!("rs", path.extension().unwrap());
+    /// ```
+    pub fn extension(&self) -> Option<&OsStr> {
+        self.file_name().map(split_file_at_dot).and_then(|(before, after)| before.and(after))
+    }
+
+    /// Creates an owned `PathBuf` with `path` adjoined to `self`.
+    ///
+    /// See `PathBuf::push` for more details on what it means to adjoin a path.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::path::{Path, PathBuf};
+    ///
+    /// assert_eq!(Path::new("/etc").join("passwd"), PathBuf::from("/etc/passwd"));
+    /// ```
+    pub fn join<P: AsRef<Path>>(&self, path: P) -> PathBuf {
+        self._join(path.as_ref())
+    }
+
+    fn _join(&self, path: &Path) -> PathBuf {
+        let mut buf = self.to_path_buf();
+        buf.push(path);
+        buf
+    }
+
+    /// Creates an owned `PathBuf` like `self` but with the given file name.
+    ///
+    /// See `PathBuf::set_file_name` for more details.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::path::{Path, PathBuf};
+    ///
+    /// let path = Path::new("/tmp/foo.txt");
+    /// assert_eq!(path.with_file_name("bar.txt"), PathBuf::from("/tmp/bar.txt"));
+    /// ```
+    pub fn with_file_name<S: AsRef<OsStr>>(&self, file_name: S) -> PathBuf {
+        self._with_file_name(file_name.as_ref())
+    }
+
+    fn _with_file_name(&self, file_name: &OsStr) -> PathBuf {
+        let mut buf = self.to_path_buf();
+        buf.set_file_name(file_name);
+        buf
+    }
+
+    /// Creates an owned `PathBuf` like `self` but with the given extension.
+    ///
+    /// See `PathBuf::set_extension` for more details.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::path::{Path, PathBuf};
+    ///
+    /// let path = Path::new("foo.rs");
+    /// assert_eq!(path.with_extension("txt"), PathBuf::from("foo.txt"));
+    /// ```
+    pub fn with_extension<S: AsRef<OsStr>>(&self, extension: S) -> PathBuf {
+        self._with_extension(extension.as_ref())
+    }
+
+    fn _with_extension(&self, extension: &OsStr) -> PathBuf {
+        let mut buf = self.to_path_buf();
+        buf.set_extension(extension);
+        buf
+    }
+
+    /// Produce an iterator over the components of the path.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::path::{Path, Component};
+    /// use std::ffi::OsStr;
+    ///
+    /// let mut components = Path::new("/tmp/foo.txt").components();
+    ///
+    /// assert_eq!(components.next(), Some(Component::RootDir));
+    /// assert_eq!(components.next(), Some(Component::Normal(OsStr::new("tmp"))));
+    /// assert_eq!(components.next(), Some(Component::Normal(OsStr::new("foo.txt"))));
+    /// assert_eq!(components.next(), None)
+    /// ```
+    pub fn components(&self) -> Components {
+        let prefix = parse_prefix(self.as_os_str());
+        Components {
+            path: self.as_u8_slice(),
+            prefix: prefix,
+            has_physical_root: has_physical_root(self.as_u8_slice(), prefix),
+            front: State::Prefix,
+            back: State::Body,
+        }
+    }
+
+    /// Produce an iterator over the path's components viewed as `OsStr` slices.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::path::{self, Path};
+    /// use std::ffi::OsStr;
+    ///
+    /// let mut it = Path::new("/tmp/foo.txt").iter();
+    /// assert_eq!(it.next(), Some(OsStr::new(&path::MAIN_SEPARATOR.to_string())));
+    /// assert_eq!(it.next(), Some(OsStr::new("tmp")));
+    /// assert_eq!(it.next(), Some(OsStr::new("foo.txt")));
+    /// assert_eq!(it.next(), None)
+    /// ```
+    pub fn iter(&self) -> Iter {
+        Iter { inner: self.components() }
+    }
+
+    /// Returns an object that implements `Display` for safely printing paths
+    /// that may contain non-Unicode data.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use std::path::Path;
+    ///
+    /// let path = Path::new("/tmp/foo.rs");
+    ///
+    /// println!("{}", path.display());
+    /// ```
+    pub fn display(&self) -> Display {
+        Display { path: self }
+    }
+
+
+    //NOTE: The following functions rely on filesystem functionality that
+    //probably have to be implemented in ctru-rs instead of this library,
+    //and thus are commented out
+
+    /*
+    /// Query the file system to get information about a file, directory, etc.
+    ///
+    /// This function will traverse symbolic links to query information about the
+    /// destination file.
+    ///
+    /// This is an alias to [`fs::metadata`].
+    ///
+    /// [`fs::metadata`]: ../fs/fn.metadata.html
+    pub fn metadata(&self) -> io::Result<fs::Metadata> {
+        fs::metadata(self)
+    }
+
+    /// Query the metadata about a file without following symlinks.
+    ///
+    /// This is an alias to [`fs::symlink_metadata`].
+    ///
+    /// [`fs::symlink_metadata`]: ../fs/fn.symlink_metadata.html
+
+    pub fn symlink_metadata(&self) -> io::Result<fs::Metadata> {
+        fs::symlink_metadata(self)
+    }
+
+
+    /// Returns the canonical form of the path with all intermediate components
+    /// normalized and symbolic links resolved.
+    ///
+    /// This is an alias to [`fs::canonicalize`].
+    ///
+    /// [`fs::canonicalize`]: ../fs/fn.canonicalize.html
+
+    pub fn canonicalize(&self) -> io::Result<PathBuf> {
+        fs::canonicalize(self)
+    }
+
+
+    /// Reads a symbolic link, returning the file that the link points to.
+    ///
+    /// This is an alias to [`fs::read_link`].
+    ///
+    /// [`fs::read_link`]: ../fs/fn.read_link.html
+
+    pub fn read_link(&self) -> io::Result<PathBuf> {
+        fs::read_link(self)
+    }
+
+
+    /// Returns an iterator over the entries within a directory.
+    ///
+    /// The iterator will yield instances of `io::Result<DirEntry>`. New errors may
+    /// be encountered after an iterator is initially constructed.
+    ///
+    /// This is an alias to [`fs::read_dir`].
+    ///
+    /// [`fs::read_dir`]: ../fs/fn.read_dir.html
+
+    pub fn read_dir(&self) -> io::Result<fs::ReadDir> {
+        fs::read_dir(self)
+    }
+
+
+    /// Returns whether the path points at an existing entity.
+    ///
+    /// This function will traverse symbolic links to query information about the
+    /// destination file. In case of broken symbolic links this will return `false`.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::path::Path;
+    /// assert_eq!(Path::new("does_not_exist.txt").exists(), false);
+    /// ```
+
+    pub fn exists(&self) -> bool {
+        fs::metadata(self).is_ok()
+    }
+
+
+    /// Returns whether the path is pointing at a regular file.
+    ///
+    /// This function will traverse symbolic links to query information about the
+    /// destination file. In case of broken symbolic links this will return `false`.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::path::Path;
+    /// assert_eq!(Path::new("./is_a_directory/").is_file(), false);
+    /// assert_eq!(Path::new("a_file.txt").is_file(), true);
+    /// ```
+
+    pub fn is_file(&self) -> bool {
+        fs::metadata(self).map(|m| m.is_file()).unwrap_or(false)
+    }
+
+
+    /// Returns whether the path is pointing at a directory.
+    ///
+    /// This function will traverse symbolic links to query information about the
+    /// destination file. In case of broken symbolic links this will return `false`.
+    ///
+    /// # Examples
+    ///
+    /// ```no_run
+    /// use std::path::Path;
+    /// assert_eq!(Path::new("./is_a_directory/").is_dir(), true);
+    /// assert_eq!(Path::new("a_file.txt").is_dir(), false);
+    /// ```
+
+    pub fn is_dir(&self) -> bool {
+        fs::metadata(self).map(|m| m.is_dir()).unwrap_or(false)
+    }
+    */
+}
+
+impl AsRef<OsStr> for Path {
+    fn as_ref(&self) -> &OsStr {
+        &self.inner
+    }
+}
+
+impl fmt::Debug for Path {
+    fn fmt(&self, formatter: &mut fmt::Formatter) -> Result<(), fmt::Error> {
+        self.inner.fmt(formatter)
+    }
+}
+
+/// Helper struct for safely printing paths with `format!()` and `{}`
+pub struct Display<'a> {
+    path: &'a Path,
+}
+
+impl<'a> fmt::Debug for Display<'a> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        fmt::Debug::fmt(&self.path.to_string_lossy(), f)
+    }
+}
+
+impl<'a> fmt::Display for Display<'a> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        fmt::Display::fmt(&self.path.to_string_lossy(), f)
+    }
+}
+
+impl cmp::PartialEq for Path {
+    fn eq(&self, other: &Path) -> bool {
+        self.components().eq(other.components())
+    }
+}
+
+impl Hash for Path {
+    fn hash<H: Hasher>(&self, h: &mut H) {
+        for component in self.components() {
+            component.hash(h);
+        }
+    }
+}
+
+impl cmp::Eq for Path {}
+
+impl cmp::PartialOrd for Path {
+    fn partial_cmp(&self, other: &Path) -> Option<cmp::Ordering> {
+        self.components().partial_cmp(other.components())
+    }
+}
+
+impl cmp::Ord for Path {
+    fn cmp(&self, other: &Path) -> cmp::Ordering {
+        self.components().cmp(other.components())
+    }
+}
+
+impl AsRef<Path> for Path {
+    fn as_ref(&self) -> &Path {
+        self
+    }
+}
+
+impl AsRef<Path> for OsStr {
+    fn as_ref(&self) -> &Path {
+        Path::new(self)
+    }
+}
+
+impl<'a> AsRef<Path> for Cow<'a, OsStr> {
+    fn as_ref(&self) -> &Path {
+        Path::new(self)
+    }
+}
+
+impl AsRef<Path> for OsString {
+    fn as_ref(&self) -> &Path {
+        Path::new(self)
+    }
+}
+
+impl AsRef<Path> for str {
+    fn as_ref(&self) -> &Path {
+        Path::new(self)
+    }
+}
+
+impl AsRef<Path> for String {
+    fn as_ref(&self) -> &Path {
+        Path::new(self)
+    }
+}
+
+impl AsRef<Path> for PathBuf {
+    fn as_ref(&self) -> &Path {
+        self
+    }
+}
+
+impl<'a> IntoIterator for &'a PathBuf {
+    type Item = &'a OsStr;
+    type IntoIter = Iter<'a>;
+    fn into_iter(self) -> Iter<'a> { self.iter() }
+}
+
+impl<'a> IntoIterator for &'a Path {
+    type Item = &'a OsStr;
+    type IntoIter = Iter<'a>;
+    fn into_iter(self) -> Iter<'a> { self.iter() }
+}
+
+macro_rules! impl_cmp {
+    ($lhs:ty, $rhs: ty) => {
+        impl<'a, 'b> PartialEq<$rhs> for $lhs {
+            #[inline]
+            fn eq(&self, other: &$rhs) -> bool { <Path as PartialEq>::eq(self, other) }
+        }
+
+        impl<'a, 'b> PartialEq<$lhs> for $rhs {
+            #[inline]
+            fn eq(&self, other: &$lhs) -> bool { <Path as PartialEq>::eq(self, other) }
+        }
+
+        impl<'a, 'b> PartialOrd<$rhs> for $lhs {
+            #[inline]
+            fn partial_cmp(&self, other: &$rhs) -> Option<cmp::Ordering> {
+                <Path as PartialOrd>::partial_cmp(self, other)
+            }
+        }
+
+        impl<'a, 'b> PartialOrd<$lhs> for $rhs {
+            #[inline]
+            fn partial_cmp(&self, other: &$lhs) -> Option<cmp::Ordering> {
+                <Path as PartialOrd>::partial_cmp(self, other)
+            }
+        }
+    }
+}
+
+impl_cmp!(PathBuf, Path);
+impl_cmp!(PathBuf, &'a Path);
+impl_cmp!(Cow<'a, Path>, Path);
+impl_cmp!(Cow<'a, Path>, &'b Path);
+impl_cmp!(Cow<'a, Path>, PathBuf);
+
+macro_rules! impl_cmp_os_str {
+    ($lhs:ty, $rhs: ty) => {
+        impl<'a, 'b> PartialEq<$rhs> for $lhs {
+            #[inline]
+            fn eq(&self, other: &$rhs) -> bool { <Path as PartialEq>::eq(self, other.as_ref()) }
+        }
+
+        impl<'a, 'b> PartialEq<$lhs> for $rhs {
+            #[inline]
+            fn eq(&self, other: &$lhs) -> bool { <Path as PartialEq>::eq(self.as_ref(), other) }
+        }
+
+        impl<'a, 'b> PartialOrd<$rhs> for $lhs {
+            #[inline]
+            fn partial_cmp(&self, other: &$rhs) -> Option<cmp::Ordering> {
+                <Path as PartialOrd>::partial_cmp(self, other.as_ref())
+            }
+        }
+
+        impl<'a, 'b> PartialOrd<$lhs> for $rhs {
+            #[inline]
+            fn partial_cmp(&self, other: &$lhs) -> Option<cmp::Ordering> {
+                <Path as PartialOrd>::partial_cmp(self.as_ref(), other)
+            }
+        }
+    }
+}
+
+impl_cmp_os_str!(PathBuf, OsStr);
+impl_cmp_os_str!(PathBuf, &'a OsStr);
+impl_cmp_os_str!(PathBuf, Cow<'a, OsStr>);
+impl_cmp_os_str!(PathBuf, OsString);
+impl_cmp_os_str!(Path, OsStr);
+impl_cmp_os_str!(Path, &'a OsStr);
+impl_cmp_os_str!(Path, Cow<'a, OsStr>);
+impl_cmp_os_str!(Path, OsString);
+impl_cmp_os_str!(&'a Path, OsStr);
+impl_cmp_os_str!(&'a Path, Cow<'b, OsStr>);
+impl_cmp_os_str!(&'a Path, OsString);
+impl_cmp_os_str!(Cow<'a, Path>, OsStr);
+impl_cmp_os_str!(Cow<'a, Path>, &'b OsStr);
+impl_cmp_os_str!(Cow<'a, Path>, OsString);
+
+/*
+impl fmt::Display for StripPrefixError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        self.description().fmt(f)
+    }
+}
+*/
+
+/*
+impl Error for StripPrefixError {
+    fn description(&self) -> &str { "prefix not found" }
+}
+*/
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use collections::string::{ToString, String};
+    use collections::borrow;
+    use collections::Vec;
+
+    macro_rules! t(
+        ($path:expr, iter: $iter:expr) => (
+            {
+                let path = Path::new($path);
+
+                // Forward iteration
+                let comps = path.iter()
+                    .map(|p| p.to_string_lossy().into_owned())
+                    .collect::<Vec<String>>();
+                let exp: &[&str] = &$iter;
+                let exps = exp.iter().map(|s| s.to_string()).collect::<Vec<String>>();
+                assert!(comps == exps, "iter: Expected {:?}, found {:?}",
+                        exps, comps);
+
+                // Reverse iteration
+                let comps = Path::new($path).iter().rev()
+                    .map(|p| p.to_string_lossy().into_owned())
+                    .collect::<Vec<String>>();
+                let exps = exps.into_iter().rev().collect::<Vec<String>>();
+                assert!(comps == exps, "iter().rev(): Expected {:?}, found {:?}",
+                        exps, comps);
+            }
+        );
+
+        ($path:expr, has_root: $has_root:expr, is_absolute: $is_absolute:expr) => (
+            {
+                let path = Path::new($path);
+
+                let act_root = path.has_root();
+                assert!(act_root == $has_root, "has_root: Expected {:?}, found {:?}",
+                        $has_root, act_root);
+
+                let act_abs = path.is_absolute();
+                assert!(act_abs == $is_absolute, "is_absolute: Expected {:?}, found {:?}",
+                        $is_absolute, act_abs);
+            }
+        );
+
+        ($path:expr, parent: $parent:expr, file_name: $file:expr) => (
+            {
+                let path = Path::new($path);
+
+                let parent = path.parent().map(|p| p.to_str().unwrap());
+                let exp_parent: Option<&str> = $parent;
+                assert!(parent == exp_parent, "parent: Expected {:?}, found {:?}",
+                        exp_parent, parent);
+
+                let file = path.file_name().map(|p| p.to_str().unwrap());
+                let exp_file: Option<&str> = $file;
+                assert!(file == exp_file, "file_name: Expected {:?}, found {:?}",
+                        exp_file, file);
+            }
+        );
+
+        ($path:expr, file_stem: $file_stem:expr, extension: $extension:expr) => (
+            {
+                let path = Path::new($path);
+
+                let stem = path.file_stem().map(|p| p.to_str().unwrap());
+                let exp_stem: Option<&str> = $file_stem;
+                assert!(stem == exp_stem, "file_stem: Expected {:?}, found {:?}",
+                        exp_stem, stem);
+
+                let ext = path.extension().map(|p| p.to_str().unwrap());
+                let exp_ext: Option<&str> = $extension;
+                assert!(ext == exp_ext, "extension: Expected {:?}, found {:?}",
+                        exp_ext, ext);
+            }
+        );
+
+        ($path:expr, iter: $iter:expr,
+                     has_root: $has_root:expr, is_absolute: $is_absolute:expr,
+                     parent: $parent:expr, file_name: $file:expr,
+                     file_stem: $file_stem:expr, extension: $extension:expr) => (
+            {
+                t!($path, iter: $iter);
+                t!($path, has_root: $has_root, is_absolute: $is_absolute);
+                t!($path, parent: $parent, file_name: $file);
+                t!($path, file_stem: $file_stem, extension: $extension);
+            }
+        );
+    );
+
+    #[test]
+    fn into() {
+        use collections::borrow::Cow;
+
+        let static_path = Path::new("/home/foo");
+        let static_cow_path: Cow<'static, Path> = static_path.into();
+        let pathbuf = PathBuf::from("/home/foo");
+
+        {
+            let path: &Path = &pathbuf;
+            let borrowed_cow_path: Cow<Path> = path.into();
+
+            assert_eq!(static_cow_path, borrowed_cow_path);
+        }
+
+        let owned_cow_path: Cow<'static, Path> = pathbuf.into();
+
+        assert_eq!(static_cow_path, owned_cow_path);
+    }
+
+    #[test]
+    #[cfg(unix)]
+    pub fn test_decompositions_unix() {
+        t!("",
+           iter: [],
+           has_root: false,
+           is_absolute: false,
+           parent: None,
+           file_name: None,
+           file_stem: None,
+           extension: None
+           );
+
+        t!("foo",
+           iter: ["foo"],
+           has_root: false,
+           is_absolute: false,
+           parent: Some(""),
+           file_name: Some("foo"),
+           file_stem: Some("foo"),
+           extension: None
+           );
+
+        t!("/",
+           iter: ["/"],
+           has_root: true,
+           is_absolute: true,
+           parent: None,
+           file_name: None,
+           file_stem: None,
+           extension: None
+           );
+
+        t!("/foo",
+           iter: ["/", "foo"],
+           has_root: true,
+           is_absolute: true,
+           parent: Some("/"),
+           file_name: Some("foo"),
+           file_stem: Some("foo"),
+           extension: None
+           );
+
+        t!("foo/",
+           iter: ["foo"],
+           has_root: false,
+           is_absolute: false,
+           parent: Some(""),
+           file_name: Some("foo"),
+           file_stem: Some("foo"),
+           extension: None
+           );
+
+        t!("/foo/",
+           iter: ["/", "foo"],
+           has_root: true,
+           is_absolute: true,
+           parent: Some("/"),
+           file_name: Some("foo"),
+           file_stem: Some("foo"),
+           extension: None
+           );
+
+        t!("foo/bar",
+           iter: ["foo", "bar"],
+           has_root: false,
+           is_absolute: false,
+           parent: Some("foo"),
+           file_name: Some("bar"),
+           file_stem: Some("bar"),
+           extension: None
+           );
+
+        t!("/foo/bar",
+           iter: ["/", "foo", "bar"],
+           has_root: true,
+           is_absolute: true,
+           parent: Some("/foo"),
+           file_name: Some("bar"),
+           file_stem: Some("bar"),
+           extension: None
+           );
+
+        t!("///foo///",
+           iter: ["/", "foo"],
+           has_root: true,
+           is_absolute: true,
+           parent: Some("/"),
+           file_name: Some("foo"),
+           file_stem: Some("foo"),
+           extension: None
+           );
+
+        t!("///foo///bar",
+           iter: ["/", "foo", "bar"],
+           has_root: true,
+           is_absolute: true,
+           parent: Some("///foo"),
+           file_name: Some("bar"),
+           file_stem: Some("bar"),
+           extension: None
+           );
+
+        t!("./.",
+           iter: ["."],
+           has_root: false,
+           is_absolute: false,
+           parent: Some(""),
+           file_name: None,
+           file_stem: None,
+           extension: None
+           );
+
+        t!("/..",
+           iter: ["/", ".."],
+           has_root: true,
+           is_absolute: true,
+           parent: Some("/"),
+           file_name: None,
+           file_stem: None,
+           extension: None
+           );
+
+        t!("../",
+           iter: [".."],
+           has_root: false,
+           is_absolute: false,
+           parent: Some(""),
+           file_name: None,
+           file_stem: None,
+           extension: None
+           );
+
+        t!("foo/.",
+           iter: ["foo"],
+           has_root: false,
+           is_absolute: false,
+           parent: Some(""),
+           file_name: Some("foo"),
+           file_stem: Some("foo"),
+           extension: None
+           );
+
+        t!("foo/..",
+           iter: ["foo", ".."],
+           has_root: false,
+           is_absolute: false,
+           parent: Some("foo"),
+           file_name: None,
+           file_stem: None,
+           extension: None
+           );
+
+        t!("foo/./",
+           iter: ["foo"],
+           has_root: false,
+           is_absolute: false,
+           parent: Some(""),
+           file_name: Some("foo"),
+           file_stem: Some("foo"),
+           extension: None
+           );
+
+        t!("foo/./bar",
+           iter: ["foo", "bar"],
+           has_root: false,
+           is_absolute: false,
+           parent: Some("foo"),
+           file_name: Some("bar"),
+           file_stem: Some("bar"),
+           extension: None
+           );
+
+        t!("foo/../",
+           iter: ["foo", ".."],
+           has_root: false,
+           is_absolute: false,
+           parent: Some("foo"),
+           file_name: None,
+           file_stem: None,
+           extension: None
+           );
+
+        t!("foo/../bar",
+           iter: ["foo", "..", "bar"],
+           has_root: false,
+           is_absolute: false,
+           parent: Some("foo/.."),
+           file_name: Some("bar"),
+           file_stem: Some("bar"),
+           extension: None
+           );
+
+        t!("./a",
+           iter: [".", "a"],
+           has_root: false,
+           is_absolute: false,
+           parent: Some("."),
+           file_name: Some("a"),
+           file_stem: Some("a"),
+           extension: None
+           );
+
+        t!(".",
+           iter: ["."],
+           has_root: false,
+           is_absolute: false,
+           parent: Some(""),
+           file_name: None,
+           file_stem: None,
+           extension: None
+           );
+
+        t!("./",
+           iter: ["."],
+           has_root: false,
+           is_absolute: false,
+           parent: Some(""),
+           file_name: None,
+           file_stem: None,
+           extension: None
+           );
+
+        t!("a/b",
+           iter: ["a", "b"],
+           has_root: false,
+           is_absolute: false,
+           parent: Some("a"),
+           file_name: Some("b"),
+           file_stem: Some("b"),
+           extension: None
+           );
+
+        t!("a//b",
+           iter: ["a", "b"],
+           has_root: false,
+           is_absolute: false,
+           parent: Some("a"),
+           file_name: Some("b"),
+           file_stem: Some("b"),
+           extension: None
+           );
+
+        t!("a/./b",
+           iter: ["a", "b"],
+           has_root: false,
+           is_absolute: false,
+           parent: Some("a"),
+           file_name: Some("b"),
+           file_stem: Some("b"),
+           extension: None
+           );
+
+        t!("a/b/c",
+           iter: ["a", "b", "c"],
+           has_root: false,
+           is_absolute: false,
+           parent: Some("a/b"),
+           file_name: Some("c"),
+           file_stem: Some("c"),
+           extension: None
+           );
+
+        t!(".foo",
+           iter: [".foo"],
+           has_root: false,
+           is_absolute: false,
+           parent: Some(""),
+           file_name: Some(".foo"),
+           file_stem: Some(".foo"),
+           extension: None
+           );
+    }
+
+    #[test]
+    #[cfg(windows)]
+    pub fn test_decompositions_windows() {
+        t!("",
+           iter: [],
+           has_root: false,
+           is_absolute: false,
+           parent: None,
+           file_name: None,
+           file_stem: None,
+           extension: None
+           );
+
+        t!("foo",
+           iter: ["foo"],
+           has_root: false,
+           is_absolute: false,
+           parent: Some(""),
+           file_name: Some("foo"),
+           file_stem: Some("foo"),
+           extension: None
+           );
+
+        t!("/",
+           iter: ["\\"],
+           has_root: true,
+           is_absolute: false,
+           parent: None,
+           file_name: None,
+           file_stem: None,
+           extension: None
+           );
+
+        t!("\\",
+           iter: ["\\"],
+           has_root: true,
+           is_absolute: false,
+           parent: None,
+           file_name: None,
+           file_stem: None,
+           extension: None
+           );
+
+        t!("c:",
+           iter: ["c:"],
+           has_root: false,
+           is_absolute: false,
+           parent: None,
+           file_name: None,
+           file_stem: None,
+           extension: None
+           );
+
+        t!("c:\\",
+           iter: ["c:", "\\"],
+           has_root: true,
+           is_absolute: true,
+           parent: None,
+           file_name: None,
+           file_stem: None,
+           extension: None
+           );
+
+        t!("c:/",
+           iter: ["c:", "\\"],
+           has_root: true,
+           is_absolute: true,
+           parent: None,
+           file_name: None,
+           file_stem: None,
+           extension: None
+           );
+
+        t!("/foo",
+           iter: ["\\", "foo"],
+           has_root: true,
+           is_absolute: false,
+           parent: Some("/"),
+           file_name: Some("foo"),
+           file_stem: Some("foo"),
+           extension: None
+           );
+
+        t!("foo/",
+           iter: ["foo"],
+           has_root: false,
+           is_absolute: false,
+           parent: Some(""),
+           file_name: Some("foo"),
+           file_stem: Some("foo"),
+           extension: None
+           );
+
+        t!("/foo/",
+           iter: ["\\", "foo"],
+           has_root: true,
+           is_absolute: false,
+           parent: Some("/"),
+           file_name: Some("foo"),
+           file_stem: Some("foo"),
+           extension: None
+           );
+
+        t!("foo/bar",
+           iter: ["foo", "bar"],
+           has_root: false,
+           is_absolute: false,
+           parent: Some("foo"),
+           file_name: Some("bar"),
+           file_stem: Some("bar"),
+           extension: None
+           );
+
+        t!("/foo/bar",
+           iter: ["\\", "foo", "bar"],
+           has_root: true,
+           is_absolute: false,
+           parent: Some("/foo"),
+           file_name: Some("bar"),
+           file_stem: Some("bar"),
+           extension: None
+           );
+
+        t!("///foo///",
+           iter: ["\\", "foo"],
+           has_root: true,
+           is_absolute: false,
+           parent: Some("/"),
+           file_name: Some("foo"),
+           file_stem: Some("foo"),
+           extension: None
+           );
+
+        t!("///foo///bar",
+           iter: ["\\", "foo", "bar"],
+           has_root: true,
+           is_absolute: false,
+           parent: Some("///foo"),
+           file_name: Some("bar"),
+           file_stem: Some("bar"),
+           extension: None
+           );
+
+        t!("./.",
+           iter: ["."],
+           has_root: false,
+           is_absolute: false,
+           parent: Some(""),
+           file_name: None,
+           file_stem: None,
+           extension: None
+           );
+
+        t!("/..",
+           iter: ["\\", ".."],
+           has_root: true,
+           is_absolute: false,
+           parent: Some("/"),
+           file_name: None,
+           file_stem: None,
+           extension: None
+           );
+
+        t!("../",
+           iter: [".."],
+           has_root: false,
+           is_absolute: false,
+           parent: Some(""),
+           file_name: None,
+           file_stem: None,
+           extension: None
+           );
+
+        t!("foo/.",
+           iter: ["foo"],
+           has_root: false,
+           is_absolute: false,
+           parent: Some(""),
+           file_name: Some("foo"),
+           file_stem: Some("foo"),
+           extension: None
+           );
+
+        t!("foo/..",
+           iter: ["foo", ".."],
+           has_root: false,
+           is_absolute: false,
+           parent: Some("foo"),
+           file_name: None,
+           file_stem: None,
+           extension: None
+           );
+
+        t!("foo/./",
+           iter: ["foo"],
+           has_root: false,
+           is_absolute: false,
+           parent: Some(""),
+           file_name: Some("foo"),
+           file_stem: Some("foo"),
+           extension: None
+           );
+
+        t!("foo/./bar",
+           iter: ["foo", "bar"],
+           has_root: false,
+           is_absolute: false,
+           parent: Some("foo"),
+           file_name: Some("bar"),
+           file_stem: Some("bar"),
+           extension: None
+           );
+
+        t!("foo/../",
+           iter: ["foo", ".."],
+           has_root: false,
+           is_absolute: false,
+           parent: Some("foo"),
+           file_name: None,
+           file_stem: None,
+           extension: None
+           );
+
+        t!("foo/../bar",
+           iter: ["foo", "..", "bar"],
+           has_root: false,
+           is_absolute: false,
+           parent: Some("foo/.."),
+           file_name: Some("bar"),
+           file_stem: Some("bar"),
+           extension: None
+           );
+
+        t!("./a",
+           iter: [".", "a"],
+           has_root: false,
+           is_absolute: false,
+           parent: Some("."),
+           file_name: Some("a"),
+           file_stem: Some("a"),
+           extension: None
+           );
+
+        t!(".",
+           iter: ["."],
+           has_root: false,
+           is_absolute: false,
+           parent: Some(""),
+           file_name: None,
+           file_stem: None,
+           extension: None
+           );
+
+        t!("./",
+           iter: ["."],
+           has_root: false,
+           is_absolute: false,
+           parent: Some(""),
+           file_name: None,
+           file_stem: None,
+           extension: None
+           );
+
+        t!("a/b",
+           iter: ["a", "b"],
+           has_root: false,
+           is_absolute: false,
+           parent: Some("a"),
+           file_name: Some("b"),
+           file_stem: Some("b"),
+           extension: None
+           );
+
+        t!("a//b",
+           iter: ["a", "b"],
+           has_root: false,
+           is_absolute: false,
+           parent: Some("a"),
+           file_name: Some("b"),
+           file_stem: Some("b"),
+           extension: None
+           );
+
+        t!("a/./b",
+           iter: ["a", "b"],
+           has_root: false,
+           is_absolute: false,
+           parent: Some("a"),
+           file_name: Some("b"),
+           file_stem: Some("b"),
+           extension: None
+           );
+
+        t!("a/b/c",
+           iter: ["a", "b", "c"],
+           has_root: false,
+           is_absolute: false,
+           parent: Some("a/b"),
+           file_name: Some("c"),
+           file_stem: Some("c"),
+           extension: None);
+
+        t!("a\\b\\c",
+           iter: ["a", "b", "c"],
+           has_root: false,
+           is_absolute: false,
+           parent: Some("a\\b"),
+           file_name: Some("c"),
+           file_stem: Some("c"),
+           extension: None
+           );
+
+        t!("\\a",
+           iter: ["\\", "a"],
+           has_root: true,
+           is_absolute: false,
+           parent: Some("\\"),
+           file_name: Some("a"),
+           file_stem: Some("a"),
+           extension: None
+           );
+
+        t!("c:\\foo.txt",
+           iter: ["c:", "\\", "foo.txt"],
+           has_root: true,
+           is_absolute: true,
+           parent: Some("c:\\"),
+           file_name: Some("foo.txt"),
+           file_stem: Some("foo"),
+           extension: Some("txt")
+           );
+
+        t!("\\\\server\\share\\foo.txt",
+           iter: ["\\\\server\\share", "\\", "foo.txt"],
+           has_root: true,
+           is_absolute: true,
+           parent: Some("\\\\server\\share\\"),
+           file_name: Some("foo.txt"),
+           file_stem: Some("foo"),
+           extension: Some("txt")
+           );
+
+        t!("\\\\server\\share",
+           iter: ["\\\\server\\share", "\\"],
+           has_root: true,
+           is_absolute: true,
+           parent: None,
+           file_name: None,
+           file_stem: None,
+           extension: None
+           );
+
+        t!("\\\\server",
+           iter: ["\\", "server"],
+           has_root: true,
+           is_absolute: false,
+           parent: Some("\\"),
+           file_name: Some("server"),
+           file_stem: Some("server"),
+           extension: None
+           );
+
+        t!("\\\\?\\bar\\foo.txt",
+           iter: ["\\\\?\\bar", "\\", "foo.txt"],
+           has_root: true,
+           is_absolute: true,
+           parent: Some("\\\\?\\bar\\"),
+           file_name: Some("foo.txt"),
+           file_stem: Some("foo"),
+           extension: Some("txt")
+           );
+
+        t!("\\\\?\\bar",
+           iter: ["\\\\?\\bar"],
+           has_root: true,
+           is_absolute: true,
+           parent: None,
+           file_name: None,
+           file_stem: None,
+           extension: None
+           );
+
+        t!("\\\\?\\",
+           iter: ["\\\\?\\"],
+           has_root: true,
+           is_absolute: true,
+           parent: None,
+           file_name: None,
+           file_stem: None,
+           extension: None
+           );
+
+        t!("\\\\?\\UNC\\server\\share\\foo.txt",
+           iter: ["\\\\?\\UNC\\server\\share", "\\", "foo.txt"],
+           has_root: true,
+           is_absolute: true,
+           parent: Some("\\\\?\\UNC\\server\\share\\"),
+           file_name: Some("foo.txt"),
+           file_stem: Some("foo"),
+           extension: Some("txt")
+           );
+
+        t!("\\\\?\\UNC\\server",
+           iter: ["\\\\?\\UNC\\server"],
+           has_root: true,
+           is_absolute: true,
+           parent: None,
+           file_name: None,
+           file_stem: None,
+           extension: None
+           );
+
+        t!("\\\\?\\UNC\\",
+           iter: ["\\\\?\\UNC\\"],
+           has_root: true,
+           is_absolute: true,
+           parent: None,
+           file_name: None,
+           file_stem: None,
+           extension: None
+           );
+
+        t!("\\\\?\\C:\\foo.txt",
+           iter: ["\\\\?\\C:", "\\", "foo.txt"],
+           has_root: true,
+           is_absolute: true,
+           parent: Some("\\\\?\\C:\\"),
+           file_name: Some("foo.txt"),
+           file_stem: Some("foo"),
+           extension: Some("txt")
+           );
+
+
+        t!("\\\\?\\C:\\",
+           iter: ["\\\\?\\C:", "\\"],
+           has_root: true,
+           is_absolute: true,
+           parent: None,
+           file_name: None,
+           file_stem: None,
+           extension: None
+           );
+
+
+        t!("\\\\?\\C:",
+           iter: ["\\\\?\\C:"],
+           has_root: true,
+           is_absolute: true,
+           parent: None,
+           file_name: None,
+           file_stem: None,
+           extension: None
+           );
+
+
+        t!("\\\\?\\foo/bar",
+           iter: ["\\\\?\\foo/bar"],
+           has_root: true,
+           is_absolute: true,
+           parent: None,
+           file_name: None,
+           file_stem: None,
+           extension: None
+           );
+
+
+        t!("\\\\?\\C:/foo",
+           iter: ["\\\\?\\C:/foo"],
+           has_root: true,
+           is_absolute: true,
+           parent: None,
+           file_name: None,
+           file_stem: None,
+           extension: None
+           );
+
+
+        t!("\\\\.\\foo\\bar",
+           iter: ["\\\\.\\foo", "\\", "bar"],
+           has_root: true,
+           is_absolute: true,
+           parent: Some("\\\\.\\foo\\"),
+           file_name: Some("bar"),
+           file_stem: Some("bar"),
+           extension: None
+           );
+
+
+        t!("\\\\.\\foo",
+           iter: ["\\\\.\\foo", "\\"],
+           has_root: true,
+           is_absolute: true,
+           parent: None,
+           file_name: None,
+           file_stem: None,
+           extension: None
+           );
+
+
+        t!("\\\\.\\foo/bar",
+           iter: ["\\\\.\\foo/bar", "\\"],
+           has_root: true,
+           is_absolute: true,
+           parent: None,
+           file_name: None,
+           file_stem: None,
+           extension: None
+           );
+
+
+        t!("\\\\.\\foo\\bar/baz",
+           iter: ["\\\\.\\foo", "\\", "bar", "baz"],
+           has_root: true,
+           is_absolute: true,
+           parent: Some("\\\\.\\foo\\bar"),
+           file_name: Some("baz"),
+           file_stem: Some("baz"),
+           extension: None
+           );
+
+
+        t!("\\\\.\\",
+           iter: ["\\\\.\\", "\\"],
+           has_root: true,
+           is_absolute: true,
+           parent: None,
+           file_name: None,
+           file_stem: None,
+           extension: None
+           );
+
+        t!("\\\\?\\a\\b\\",
+           iter: ["\\\\?\\a", "\\", "b"],
+           has_root: true,
+           is_absolute: true,
+           parent: Some("\\\\?\\a\\"),
+           file_name: Some("b"),
+           file_stem: Some("b"),
+           extension: None
+           );
+    }
+
+    #[test]
+    pub fn test_stem_ext() {
+        t!("foo",
+           file_stem: Some("foo"),
+           extension: None
+           );
+
+        t!("foo.",
+           file_stem: Some("foo"),
+           extension: Some("")
+           );
+
+        t!(".foo",
+           file_stem: Some(".foo"),
+           extension: None
+           );
+
+        t!("foo.txt",
+           file_stem: Some("foo"),
+           extension: Some("txt")
+           );
+
+        t!("foo.bar.txt",
+           file_stem: Some("foo.bar"),
+           extension: Some("txt")
+           );
+
+        t!("foo.bar.",
+           file_stem: Some("foo.bar"),
+           extension: Some("")
+           );
+
+        t!(".",
+           file_stem: None,
+           extension: None
+           );
+
+        t!("..",
+           file_stem: None,
+           extension: None
+           );
+
+        t!("",
+           file_stem: None,
+           extension: None
+           );
+    }
+
+    #[test]
+    pub fn test_push() {
+        macro_rules! tp(
+            ($path:expr, $push:expr, $expected:expr) => ( {
+                let mut actual = PathBuf::from($path);
+                actual.push($push);
+                assert!(actual.to_str() == Some($expected),
+                        "pushing {:?} onto {:?}: Expected {:?}, got {:?}",
+                        $push, $path, $expected, actual.to_str().unwrap());
+            });
+        );
+
+        if cfg!(unix) {
+            tp!("", "foo", "foo");
+            tp!("foo", "bar", "foo/bar");
+            tp!("foo/", "bar", "foo/bar");
+            tp!("foo//", "bar", "foo//bar");
+            tp!("foo/.", "bar", "foo/./bar");
+            tp!("foo./.", "bar", "foo././bar");
+            tp!("foo", "", "foo/");
+            tp!("foo", ".", "foo/.");
+            tp!("foo", "..", "foo/..");
+            tp!("foo", "/", "/");
+            tp!("/foo/bar", "/", "/");
+            tp!("/foo/bar", "/baz", "/baz");
+            tp!("/foo/bar", "./baz", "/foo/bar/./baz");
+        } else {
+            tp!("", "foo", "foo");
+            tp!("foo", "bar", r"foo\bar");
+            tp!("foo/", "bar", r"foo/bar");
+            tp!(r"foo\", "bar", r"foo\bar");
+            tp!("foo//", "bar", r"foo//bar");
+            tp!(r"foo\\", "bar", r"foo\\bar");
+            tp!("foo/.", "bar", r"foo/.\bar");
+            tp!("foo./.", "bar", r"foo./.\bar");
+            tp!(r"foo\.", "bar", r"foo\.\bar");
+            tp!(r"foo.\.", "bar", r"foo.\.\bar");
+            tp!("foo", "", "foo\\");
+            tp!("foo", ".", r"foo\.");
+            tp!("foo", "..", r"foo\..");
+            tp!("foo", "/", "/");
+            tp!("foo", r"\", r"\");
+            tp!("/foo/bar", "/", "/");
+            tp!(r"\foo\bar", r"\", r"\");
+            tp!("/foo/bar", "/baz", "/baz");
+            tp!("/foo/bar", r"\baz", r"\baz");
+            tp!("/foo/bar", "./baz", r"/foo/bar\./baz");
+            tp!("/foo/bar", r".\baz", r"/foo/bar\.\baz");
+
+            tp!("c:\\", "windows", "c:\\windows");
+            tp!("c:", "windows", "c:windows");
+
+            tp!("a\\b\\c", "d", "a\\b\\c\\d");
+            tp!("\\a\\b\\c", "d", "\\a\\b\\c\\d");
+            tp!("a\\b", "c\\d", "a\\b\\c\\d");
+            tp!("a\\b", "\\c\\d", "\\c\\d");
+            tp!("a\\b", ".", "a\\b\\.");
+            tp!("a\\b", "..\\c", "a\\b\\..\\c");
+            tp!("a\\b", "C:a.txt", "C:a.txt");
+            tp!("a\\b", "C:\\a.txt", "C:\\a.txt");
+            tp!("C:\\a", "C:\\b.txt", "C:\\b.txt");
+            tp!("C:\\a\\b\\c", "C:d", "C:d");
+            tp!("C:a\\b\\c", "C:d", "C:d");
+            tp!("C:", r"a\b\c", r"C:a\b\c");
+            tp!("C:", r"..\a", r"C:..\a");
+            tp!("\\\\server\\share\\foo",
+                "bar",
+                "\\\\server\\share\\foo\\bar");
+            tp!("\\\\server\\share\\foo", "C:baz", "C:baz");
+            tp!("\\\\?\\C:\\a\\b", "C:c\\d", "C:c\\d");
+            tp!("\\\\?\\C:a\\b", "C:c\\d", "C:c\\d");
+            tp!("\\\\?\\C:\\a\\b", "C:\\c\\d", "C:\\c\\d");
+            tp!("\\\\?\\foo\\bar", "baz", "\\\\?\\foo\\bar\\baz");
+            tp!("\\\\?\\UNC\\server\\share\\foo",
+                "bar",
+                "\\\\?\\UNC\\server\\share\\foo\\bar");
+            tp!("\\\\?\\UNC\\server\\share", "C:\\a", "C:\\a");
+            tp!("\\\\?\\UNC\\server\\share", "C:a", "C:a");
+
+            // Note: modified from old path API
+            tp!("\\\\?\\UNC\\server", "foo", "\\\\?\\UNC\\server\\foo");
+
+            tp!("C:\\a",
+                "\\\\?\\UNC\\server\\share",
+                "\\\\?\\UNC\\server\\share");
+            tp!("\\\\.\\foo\\bar", "baz", "\\\\.\\foo\\bar\\baz");
+            tp!("\\\\.\\foo\\bar", "C:a", "C:a");
+            // again, not sure about the following, but I'm assuming \\.\ should be verbatim
+            tp!("\\\\.\\foo", "..\\bar", "\\\\.\\foo\\..\\bar");
+
+            tp!("\\\\?\\C:", "foo", "\\\\?\\C:\\foo"); // this is a weird one
+        }
+    }
+
+    #[test]
+    pub fn test_pop() {
+        macro_rules! tp(
+            ($path:expr, $expected:expr, $output:expr) => ( {
+                let mut actual = PathBuf::from($path);
+                let output = actual.pop();
+                assert!(actual.to_str() == Some($expected) && output == $output,
+                        "popping from {:?}: Expected {:?}/{:?}, got {:?}/{:?}",
+                        $path, $expected, $output,
+                        actual.to_str().unwrap(), output);
+            });
+        );
+
+        tp!("", "", false);
+        tp!("/", "/", false);
+        tp!("foo", "", true);
+        tp!(".", "", true);
+        tp!("/foo", "/", true);
+        tp!("/foo/bar", "/foo", true);
+        tp!("foo/bar", "foo", true);
+        tp!("foo/.", "", true);
+        tp!("foo//bar", "foo", true);
+
+        if cfg!(windows) {
+            tp!("a\\b\\c", "a\\b", true);
+            tp!("\\a", "\\", true);
+            tp!("\\", "\\", false);
+
+            tp!("C:\\a\\b", "C:\\a", true);
+            tp!("C:\\a", "C:\\", true);
+            tp!("C:\\", "C:\\", false);
+            tp!("C:a\\b", "C:a", true);
+            tp!("C:a", "C:", true);
+            tp!("C:", "C:", false);
+            tp!("\\\\server\\share\\a\\b", "\\\\server\\share\\a", true);
+            tp!("\\\\server\\share\\a", "\\\\server\\share\\", true);
+            tp!("\\\\server\\share", "\\\\server\\share", false);
+            tp!("\\\\?\\a\\b\\c", "\\\\?\\a\\b", true);
+            tp!("\\\\?\\a\\b", "\\\\?\\a\\", true);
+            tp!("\\\\?\\a", "\\\\?\\a", false);
+            tp!("\\\\?\\C:\\a\\b", "\\\\?\\C:\\a", true);
+            tp!("\\\\?\\C:\\a", "\\\\?\\C:\\", true);
+            tp!("\\\\?\\C:\\", "\\\\?\\C:\\", false);
+            tp!("\\\\?\\UNC\\server\\share\\a\\b",
+                "\\\\?\\UNC\\server\\share\\a",
+                true);
+            tp!("\\\\?\\UNC\\server\\share\\a",
+                "\\\\?\\UNC\\server\\share\\",
+                true);
+            tp!("\\\\?\\UNC\\server\\share",
+                "\\\\?\\UNC\\server\\share",
+                false);
+            tp!("\\\\.\\a\\b\\c", "\\\\.\\a\\b", true);
+            tp!("\\\\.\\a\\b", "\\\\.\\a\\", true);
+            tp!("\\\\.\\a", "\\\\.\\a", false);
+
+            tp!("\\\\?\\a\\b\\", "\\\\?\\a\\", true);
+        }
+    }
+
+    #[test]
+    pub fn test_set_file_name() {
+        macro_rules! tfn(
+                ($path:expr, $file:expr, $expected:expr) => ( {
+                let mut p = PathBuf::from($path);
+                p.set_file_name($file);
+                assert!(p.to_str() == Some($expected),
+                        "setting file name of {:?} to {:?}: Expected {:?}, got {:?}",
+                        $path, $file, $expected,
+                        p.to_str().unwrap());
+            });
+        );
+
+        tfn!("foo", "foo", "foo");
+        tfn!("foo", "bar", "bar");
+        tfn!("foo", "", "");
+        tfn!("", "foo", "foo");
+        if cfg!(unix) {
+            tfn!(".", "foo", "./foo");
+            tfn!("foo/", "bar", "bar");
+            tfn!("foo/.", "bar", "bar");
+            tfn!("..", "foo", "../foo");
+            tfn!("foo/..", "bar", "foo/../bar");
+            tfn!("/", "foo", "/foo");
+        } else {
+            tfn!(".", "foo", r".\foo");
+            tfn!(r"foo\", "bar", r"bar");
+            tfn!(r"foo\.", "bar", r"bar");
+            tfn!("..", "foo", r"..\foo");
+            tfn!(r"foo\..", "bar", r"foo\..\bar");
+            tfn!(r"\", "foo", r"\foo");
+        }
+    }
+
+    #[test]
+    pub fn test_set_extension() {
+        macro_rules! tfe(
+                ($path:expr, $ext:expr, $expected:expr, $output:expr) => ( {
+                let mut p = PathBuf::from($path);
+                let output = p.set_extension($ext);
+                assert!(p.to_str() == Some($expected) && output == $output,
+                        "setting extension of {:?} to {:?}: Expected {:?}/{:?}, got {:?}/{:?}",
+                        $path, $ext, $expected, $output,
+                        p.to_str().unwrap(), output);
+            });
+        );
+
+        tfe!("foo", "txt", "foo.txt", true);
+        tfe!("foo.bar", "txt", "foo.txt", true);
+        tfe!("foo.bar.baz", "txt", "foo.bar.txt", true);
+        tfe!(".test", "txt", ".test.txt", true);
+        tfe!("foo.txt", "", "foo", true);
+        tfe!("foo", "", "foo", true);
+        tfe!("", "foo", "", false);
+        tfe!(".", "foo", ".", false);
+        tfe!("foo/", "bar", "foo.bar", true);
+        tfe!("foo/.", "bar", "foo.bar", true);
+        tfe!("..", "foo", "..", false);
+        tfe!("foo/..", "bar", "foo/..", false);
+        tfe!("/", "foo", "/", false);
+    }
+
+    #[test]
+    fn test_eq_recievers() {
+        use collections::borrow::Cow;
+
+        let borrowed: &Path = Path::new("foo/bar");
+        let mut owned: PathBuf = PathBuf::new();
+        owned.push("foo");
+        owned.push("bar");
+        let borrowed_cow: Cow<Path> = borrowed.into();
+        let owned_cow: Cow<Path> = owned.clone().into();
+
+        macro_rules! t {
+            ($($current:expr),+) => {
+                $(
+                    assert_eq!($current, borrowed);
+                    assert_eq!($current, owned);
+                    assert_eq!($current, borrowed_cow);
+                    assert_eq!($current, owned_cow);
+                )+
+            }
+        }
+
+        t!(borrowed, owned, borrowed_cow, owned_cow);
+    }
+
+    #[test]
+    pub fn test_compare() {
+        use core::hash::{Hash, Hasher, SipHasher};
+
+        fn hash<T: Hash>(t: T) -> u64 {
+            let mut s = SipHasher::new_with_keys(0, 0);
+            t.hash(&mut s);
+            s.finish()
+        }
+
+        macro_rules! tc(
+            ($path1:expr, $path2:expr, eq: $eq:expr,
+             starts_with: $starts_with:expr, ends_with: $ends_with:expr,
+             relative_from: $relative_from:expr) => ({
+                 let path1 = Path::new($path1);
+                 let path2 = Path::new($path2);
+
+                 let eq = path1 == path2;
+                 assert!(eq == $eq, "{:?} == {:?}, expected {:?}, got {:?}",
+                         $path1, $path2, $eq, eq);
+                 assert!($eq == (hash(path1) == hash(path2)),
+                         "{:?} == {:?}, expected {:?}, got {} and {}",
+                         $path1, $path2, $eq, hash(path1), hash(path2));
+
+                 let starts_with = path1.starts_with(path2);
+                 assert!(starts_with == $starts_with,
+                         "{:?}.starts_with({:?}), expected {:?}, got {:?}", $path1, $path2,
+                         $starts_with, starts_with);
+
+                 let ends_with = path1.ends_with(path2);
+                 assert!(ends_with == $ends_with,
+                         "{:?}.ends_with({:?}), expected {:?}, got {:?}", $path1, $path2,
+                         $ends_with, ends_with);
+
+                 let relative_from = path1.strip_prefix(path2)
+                                          .map(|p| p.to_str().unwrap())
+                                          .ok();
+                 let exp: Option<&str> = $relative_from;
+                 assert!(relative_from == exp,
+                         "{:?}.strip_prefix({:?}), expected {:?}, got {:?}",
+                         $path1, $path2, exp, relative_from);
+            });
+        );
+
+        tc!("", "",
+            eq: true,
+            starts_with: true,
+            ends_with: true,
+            relative_from: Some("")
+            );
+
+        tc!("foo", "",
+            eq: false,
+            starts_with: true,
+            ends_with: true,
+            relative_from: Some("foo")
+            );
+
+        tc!("", "foo",
+            eq: false,
+            starts_with: false,
+            ends_with: false,
+            relative_from: None
+            );
+
+        tc!("foo", "foo",
+            eq: true,
+            starts_with: true,
+            ends_with: true,
+            relative_from: Some("")
+            );
+
+        tc!("foo/", "foo",
+            eq: true,
+            starts_with: true,
+            ends_with: true,
+            relative_from: Some("")
+            );
+
+        tc!("foo/bar", "foo",
+            eq: false,
+            starts_with: true,
+            ends_with: false,
+            relative_from: Some("bar")
+            );
+
+        tc!("foo/bar/baz", "foo/bar",
+            eq: false,
+            starts_with: true,
+            ends_with: false,
+            relative_from: Some("baz")
+            );
+
+        tc!("foo/bar", "foo/bar/baz",
+            eq: false,
+            starts_with: false,
+            ends_with: false,
+            relative_from: None
+            );
+
+        tc!("./foo/bar/", ".",
+            eq: false,
+            starts_with: true,
+            ends_with: false,
+            relative_from: Some("foo/bar")
+            );
+
+        if cfg!(windows) {
+            tc!(r"C:\src\rust\cargo-test\test\Cargo.toml",
+                r"c:\src\rust\cargo-test\test",
+                eq: false,
+                starts_with: true,
+                ends_with: false,
+                relative_from: Some("Cargo.toml")
+                );
+
+            tc!(r"c:\foo", r"C:\foo",
+                eq: true,
+                starts_with: true,
+                ends_with: true,
+                relative_from: Some("")
+                );
+        }
+    }
+}
diff --git a/src/sys/mod.rs b/src/sys/mod.rs
new file mode 100644
index 0000000..86f49e5
--- /dev/null
+++ b/src/sys/mod.rs
@@ -0,0 +1,25 @@
+/// A trait for viewing representations from std types
+#[doc(hidden)]
+pub trait AsInner<Inner: ?Sized> {
+    fn as_inner(&self) -> &Inner;
+}
+
+/// A trait for viewing representations from std types
+#[doc(hidden)]
+pub trait AsInnerMut<Inner: ?Sized> {
+    fn as_inner_mut(&mut self) -> &mut Inner;
+}
+
+/// A trait for extracting representations from std types
+#[doc(hidden)]
+pub trait IntoInner<Inner> {
+    fn into_inner(self) -> Inner;
+}
+
+/// A trait for creating std types from internal representations
+#[doc(hidden)]
+pub trait FromInner<Inner> {
+    fn from_inner(inner: Inner) -> Self;
+}
+
+pub mod wtf8;
diff --git a/src/sys/wtf8.rs b/src/sys/wtf8.rs
new file mode 100644
index 0000000..25c21c7
--- /dev/null
+++ b/src/sys/wtf8.rs
@@ -0,0 +1,1199 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! Implementation of [the WTF-8 encoding](https://simonsapin.github.io/wtf-8/).
+//!
+//! This library uses Rust’s type system to maintain
+//! [well-formedness](https://simonsapin.github.io/wtf-8/#well-formed),
+//! like the `String` and `&str` types do for UTF-8.
+//!
+//! Since [WTF-8 must not be used
+//! for interchange](https://simonsapin.github.io/wtf-8/#intended-audience),
+//! this library deliberately does not provide access to the underlying bytes
+//! of WTF-8 strings,
+//! nor can it decode WTF-8 from arbitrary bytes.
+//! WTF-8 strings can be obtained from UTF-8, UTF-16, or code points.
+
+// this module is imported from @SimonSapin's repo and has tons of dead code on
+// unix (it's mostly used on windows), so don't worry about dead code here.
+#![allow(dead_code)]
+
+use core::str::next_code_point;
+
+use ascii::*;
+use collections::borrow::Cow;
+use rustc_unicode::char;
+use core::fmt;
+use core::hash::{Hash, Hasher};
+use core::iter::FromIterator;
+use core::mem;
+use core::ops;
+use collections::slice;
+use core::str;
+use collections::String;
+use sys::AsInner;
+use collections::Vec;
+
+const UTF8_REPLACEMENT_CHARACTER: &'static [u8] = b"\xEF\xBF\xBD";
+
+/// A Unicode code point: from U+0000 to U+10FFFF.
+///
+/// Compare with the `char` type,
+/// which represents a Unicode scalar value:
+/// a code point that is not a surrogate (U+D800 to U+DFFF).
+#[derive(Eq, PartialEq, Ord, PartialOrd, Clone, Copy)]
+pub struct CodePoint {
+    value: u32,
+}
+
+/// Format the code point as `U+` followed by four to six hexadecimal digits.
+/// Example: `U+1F4A9`
+impl fmt::Debug for CodePoint {
+    #[inline]
+    fn fmt(&self, formatter: &mut fmt::Formatter) -> Result<(), fmt::Error> {
+        write!(formatter, "U+{:04X}", self.value)
+    }
+}
+
+impl CodePoint {
+    /// Unsafely creates a new `CodePoint` without checking the value.
+    ///
+    /// Only use when `value` is known to be less than or equal to 0x10FFFF.
+    #[inline]
+    pub unsafe fn from_u32_unchecked(value: u32) -> CodePoint {
+        CodePoint { value: value }
+    }
+
+    /// Creates a new `CodePoint` if the value is a valid code point.
+    ///
+    /// Returns `None` if `value` is above 0x10FFFF.
+    #[inline]
+    pub fn from_u32(value: u32) -> Option<CodePoint> {
+        match value {
+            0...0x10FFFF => Some(CodePoint { value: value }),
+            _ => None,
+        }
+    }
+
+    /// Creates a new `CodePoint` from a `char`.
+    ///
+    /// Since all Unicode scalar values are code points, this always succeeds.
+    #[inline]
+    pub fn from_char(value: char) -> CodePoint {
+        CodePoint { value: value as u32 }
+    }
+
+    /// Returns the numeric value of the code point.
+    #[inline]
+    pub fn to_u32(&self) -> u32 {
+        self.value
+    }
+
+    /// Optionally returns a Unicode scalar value for the code point.
+    ///
+    /// Returns `None` if the code point is a surrogate (from U+D800 to U+DFFF).
+    #[inline]
+    pub fn to_char(&self) -> Option<char> {
+        match self.value {
+            0xD800...0xDFFF => None,
+            _ => Some(unsafe { char::from_u32_unchecked(self.value) }),
+        }
+    }
+
+    /// Returns a Unicode scalar value for the code point.
+    ///
+    /// Returns `'\u{FFFD}'` (the replacement character “�”)
+    /// if the code point is a surrogate (from U+D800 to U+DFFF).
+    #[inline]
+    pub fn to_char_lossy(&self) -> char {
+        self.to_char().unwrap_or('\u{FFFD}')
+    }
+}
+
+/// An owned, growable string of well-formed WTF-8 data.
+///
+/// Similar to `String`, but can additionally contain surrogate code points
+/// if they’re not in a surrogate pair.
+#[derive(Eq, PartialEq, Ord, PartialOrd, Clone)]
+pub struct Wtf8Buf {
+    bytes: Vec<u8>,
+}
+
+impl ops::Deref for Wtf8Buf {
+    type Target = Wtf8;
+
+    fn deref(&self) -> &Wtf8 {
+        self.as_slice()
+    }
+}
+
+/// Format the string with double quotes,
+/// and surrogates as `\u` followed by four hexadecimal digits.
+/// Example: `"a\u{D800}"` for a string with code points [U+0061, U+D800]
+impl fmt::Debug for Wtf8Buf {
+    #[inline]
+    fn fmt(&self, formatter: &mut fmt::Formatter) -> Result<(), fmt::Error> {
+        fmt::Debug::fmt(&**self, formatter)
+    }
+}
+
+impl Wtf8Buf {
+    /// Creates a new, empty WTF-8 string.
+    #[inline]
+    pub fn new() -> Wtf8Buf {
+        Wtf8Buf { bytes: Vec::new() }
+    }
+
+    /// Creates a new, empty WTF-8 string with pre-allocated capacity for `n` bytes.
+    #[inline]
+    pub fn with_capacity(n: usize) -> Wtf8Buf {
+        Wtf8Buf { bytes: Vec::with_capacity(n) }
+    }
+
+    /// Creates a WTF-8 string from a UTF-8 `String`.
+    ///
+    /// This takes ownership of the `String` and does not copy.
+    ///
+    /// Since WTF-8 is a superset of UTF-8, this always succeeds.
+    #[inline]
+    pub fn from_string(string: String) -> Wtf8Buf {
+        Wtf8Buf { bytes: string.into_bytes() }
+    }
+
+    /// Creates a WTF-8 string from a UTF-8 `&str` slice.
+    ///
+    /// This copies the content of the slice.
+    ///
+    /// Since WTF-8 is a superset of UTF-8, this always succeeds.
+    #[inline]
+    pub fn from_str(str: &str) -> Wtf8Buf {
+        Wtf8Buf { bytes: <[_]>::to_vec(str.as_bytes()) }
+    }
+
+    pub fn clear(&mut self) {
+        self.bytes.clear()
+    }
+
+    /// Creates a WTF-8 string from a potentially ill-formed UTF-16 slice of 16-bit code units.
+    ///
+    /// This is lossless: calling `.encode_wide()` on the resulting string
+    /// will always return the original code units.
+    pub fn from_wide(v: &[u16]) -> Wtf8Buf {
+        let mut string = Wtf8Buf::with_capacity(v.len());
+        for item in char::decode_utf16(v.iter().cloned()) {
+            match item {
+                Ok(ch) => string.push_char(ch),
+                Err(surrogate) => {
+                    let surrogate = surrogate.unpaired_surrogate();
+                    // Surrogates are known to be in the code point range.
+                    let code_point = unsafe { CodePoint::from_u32_unchecked(surrogate as u32) };
+                    // Skip the WTF-8 concatenation check,
+                    // surrogate pairs are already decoded by decode_utf16
+                    string.push_code_point_unchecked(code_point)
+                }
+            }
+        }
+        string
+    }
+
+    /// Copied from String::push
+    /// This does **not** include the WTF-8 concatenation check.
+    fn push_code_point_unchecked(&mut self, code_point: CodePoint) {
+        let bytes = unsafe { char::from_u32_unchecked(code_point.value).encode_utf8() };
+        self.bytes.extend_from_slice(bytes.as_slice());
+    }
+
+    #[inline]
+    pub fn as_slice(&self) -> &Wtf8 {
+        unsafe { Wtf8::from_bytes_unchecked(&self.bytes) }
+    }
+
+    /// Reserves capacity for at least `additional` more bytes to be inserted
+    /// in the given `Wtf8Buf`.
+    /// The collection may reserve more space to avoid frequent reallocations.
+    ///
+    /// # Panics
+    ///
+    /// Panics if the new capacity overflows `usize`.
+    #[inline]
+    pub fn reserve(&mut self, additional: usize) {
+        self.bytes.reserve(additional)
+    }
+
+    #[inline]
+    pub fn reserve_exact(&mut self, additional: usize) {
+        self.bytes.reserve_exact(additional)
+    }
+
+    /// Returns the number of bytes that this string buffer can hold without reallocating.
+    #[inline]
+    pub fn capacity(&self) -> usize {
+        self.bytes.capacity()
+    }
+
+    /// Append a UTF-8 slice at the end of the string.
+    #[inline]
+    pub fn push_str(&mut self, other: &str) {
+        self.bytes.extend_from_slice(other.as_bytes())
+    }
+
+    /// Append a WTF-8 slice at the end of the string.
+    ///
+    /// This replaces newly paired surrogates at the boundary
+    /// with a supplementary code point,
+    /// like concatenating ill-formed UTF-16 strings effectively would.
+    #[inline]
+    pub fn push_wtf8(&mut self, other: &Wtf8) {
+        match ((&*self).final_lead_surrogate(), other.initial_trail_surrogate()) {
+            // Replace newly paired surrogates by a supplementary code point.
+            (Some(lead), Some(trail)) => {
+                let len_without_lead_surrogate = self.len() - 3;
+                self.bytes.truncate(len_without_lead_surrogate);
+                let other_without_trail_surrogate = &other.bytes[3..];
+                // 4 bytes for the supplementary code point
+                self.bytes.reserve(4 + other_without_trail_surrogate.len());
+                self.push_char(decode_surrogate_pair(lead, trail));
+                self.bytes.extend_from_slice(other_without_trail_surrogate);
+            }
+            _ => self.bytes.extend_from_slice(&other.bytes),
+        }
+    }
+
+    /// Append a Unicode scalar value at the end of the string.
+    #[inline]
+    pub fn push_char(&mut self, c: char) {
+        self.push_code_point_unchecked(CodePoint::from_char(c))
+    }
+
+    /// Append a code point at the end of the string.
+    ///
+    /// This replaces newly paired surrogates at the boundary
+    /// with a supplementary code point,
+    /// like concatenating ill-formed UTF-16 strings effectively would.
+    #[inline]
+    pub fn push(&mut self, code_point: CodePoint) {
+        if let trail @ 0xDC00...0xDFFF = code_point.to_u32() {
+            if let Some(lead) = (&*self).final_lead_surrogate() {
+                let len_without_lead_surrogate = self.len() - 3;
+                self.bytes.truncate(len_without_lead_surrogate);
+                self.push_char(decode_surrogate_pair(lead, trail as u16));
+                return;
+            }
+        }
+
+        // No newly paired surrogates at the boundary.
+        self.push_code_point_unchecked(code_point)
+    }
+
+    /// Shortens a string to the specified length.
+    ///
+    /// # Panics
+    ///
+    /// Panics if `new_len` > current length,
+    /// or if `new_len` is not a code point boundary.
+    #[inline]
+    pub fn truncate(&mut self, new_len: usize) {
+        assert!(is_code_point_boundary(self, new_len));
+        self.bytes.truncate(new_len)
+    }
+
+    /// Consumes the WTF-8 string and tries to convert it to UTF-8.
+    ///
+    /// This does not copy the data.
+    ///
+    /// If the contents are not well-formed UTF-8
+    /// (that is, if the string contains surrogates),
+    /// the original WTF-8 string is returned instead.
+    pub fn into_string(self) -> Result<String, Wtf8Buf> {
+        match self.next_surrogate(0) {
+            None => Ok(unsafe { String::from_utf8_unchecked(self.bytes) }),
+            Some(_) => Err(self),
+        }
+    }
+
+    /// Consumes the WTF-8 string and converts it lossily to UTF-8.
+    ///
+    /// This does not copy the data (but may overwrite parts of it in place).
+    ///
+    /// Surrogates are replaced with `"\u{FFFD}"` (the replacement character “�”)
+    pub fn into_string_lossy(mut self) -> String {
+        let mut pos = 0;
+        loop {
+            match self.next_surrogate(pos) {
+                Some((surrogate_pos, _)) => {
+                    pos = surrogate_pos + 3;
+                    self.bytes[surrogate_pos..pos].copy_from_slice(UTF8_REPLACEMENT_CHARACTER);
+                }
+                None => return unsafe { String::from_utf8_unchecked(self.bytes) },
+            }
+        }
+    }
+}
+
+/// Create a new WTF-8 string from an iterator of code points.
+///
+/// This replaces surrogate code point pairs with supplementary code points,
+/// like concatenating ill-formed UTF-16 strings effectively would.
+impl FromIterator<CodePoint> for Wtf8Buf {
+    fn from_iter<T: IntoIterator<Item = CodePoint>>(iter: T) -> Wtf8Buf {
+        let mut string = Wtf8Buf::new();
+        string.extend(iter);
+        string
+    }
+}
+
+/// Append code points from an iterator to the string.
+///
+/// This replaces surrogate code point pairs with supplementary code points,
+/// like concatenating ill-formed UTF-16 strings effectively would.
+impl Extend<CodePoint> for Wtf8Buf {
+    fn extend<T: IntoIterator<Item = CodePoint>>(&mut self, iter: T) {
+        let iterator = iter.into_iter();
+        let (low, _high) = iterator.size_hint();
+        // Lower bound of one byte per code point (ASCII only)
+        self.bytes.reserve(low);
+        for code_point in iterator {
+            self.push(code_point);
+        }
+    }
+}
+
+/// A borrowed slice of well-formed WTF-8 data.
+///
+/// Similar to `&str`, but can additionally contain surrogate code points
+/// if they’re not in a surrogate pair.
+#[derive(Eq, Ord, PartialEq, PartialOrd)]
+pub struct Wtf8 {
+    bytes: [u8],
+}
+
+impl AsInner<[u8]> for Wtf8 {
+    fn as_inner(&self) -> &[u8] {
+        &self.bytes
+    }
+}
+
+/// Format the slice with double quotes,
+/// and surrogates as `\u` followed by four hexadecimal digits.
+/// Example: `"a\u{D800}"` for a slice with code points [U+0061, U+D800]
+impl fmt::Debug for Wtf8 {
+    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
+        fn write_str_escaped(f: &mut fmt::Formatter, s: &str) -> fmt::Result {
+            use core::fmt::Write;
+            for c in s.chars().flat_map(|c| c.escape_debug()) {
+                f.write_char(c)?
+            }
+            Ok(())
+        }
+
+        formatter.write_str("\"")?;
+        let mut pos = 0;
+        loop {
+            match self.next_surrogate(pos) {
+                None => break,
+                Some((surrogate_pos, surrogate)) => {
+                    write_str_escaped(formatter, unsafe {
+                            str::from_utf8_unchecked(&self.bytes[pos..surrogate_pos])
+                        })
+                        ?;
+                    write!(formatter, "\\u{{{:x}}}", surrogate)?;
+                    pos = surrogate_pos + 3;
+                }
+            }
+        }
+        write_str_escaped(formatter,
+                          unsafe { str::from_utf8_unchecked(&self.bytes[pos..]) })
+            ?;
+        formatter.write_str("\"")
+    }
+}
+
+impl Wtf8 {
+    /// Creates a WTF-8 slice from a UTF-8 `&str` slice.
+    ///
+    /// Since WTF-8 is a superset of UTF-8, this always succeeds.
+    #[inline]
+    pub fn from_str(value: &str) -> &Wtf8 {
+        unsafe { Wtf8::from_bytes_unchecked(value.as_bytes()) }
+    }
+
+    /// Creates a WTF-8 slice from a WTF-8 byte slice.
+    ///
+    /// Since the byte slice is not checked for valid WTF-8, this functions is
+    /// marked unsafe.
+    #[inline]
+    unsafe fn from_bytes_unchecked(value: &[u8]) -> &Wtf8 {
+        mem::transmute(value)
+    }
+
+    /// Returns the length, in WTF-8 bytes.
+    #[inline]
+    pub fn len(&self) -> usize {
+        self.bytes.len()
+    }
+
+    #[inline]
+    pub fn is_empty(&self) -> bool {
+        self.bytes.is_empty()
+    }
+
+    /// Returns the code point at `position` if it is in the ASCII range,
+    /// or `b'\xFF' otherwise.
+    ///
+    /// # Panics
+    ///
+    /// Panics if `position` is beyond the end of the string.
+    #[inline]
+    pub fn ascii_byte_at(&self, position: usize) -> u8 {
+        match self.bytes[position] {
+            ascii_byte @ 0x00...0x7F => ascii_byte,
+            _ => 0xFF,
+        }
+    }
+
+    /// Returns an iterator for the string’s code points.
+    #[inline]
+    pub fn code_points(&self) -> Wtf8CodePoints {
+        Wtf8CodePoints { bytes: self.bytes.iter() }
+    }
+
+    /// Tries to convert the string to UTF-8 and return a `&str` slice.
+    ///
+    /// Returns `None` if the string contains surrogates.
+    ///
+    /// This does not copy the data.
+    #[inline]
+    pub fn as_str(&self) -> Option<&str> {
+        // Well-formed WTF-8 is also well-formed UTF-8
+        // if and only if it contains no surrogate.
+        match self.next_surrogate(0) {
+            None => Some(unsafe { str::from_utf8_unchecked(&self.bytes) }),
+            Some(_) => None,
+        }
+    }
+
+    /// Lossily converts the string to UTF-8.
+    /// Returns a UTF-8 `&str` slice if the contents are well-formed in UTF-8.
+    ///
+    /// Surrogates are replaced with `"\u{FFFD}"` (the replacement character “�”).
+    ///
+    /// This only copies the data if necessary (if it contains any surrogate).
+    pub fn to_string_lossy(&self) -> Cow<str> {
+        let surrogate_pos = match self.next_surrogate(0) {
+            None => return Cow::Borrowed(unsafe { str::from_utf8_unchecked(&self.bytes) }),
+            Some((pos, _)) => pos,
+        };
+        let wtf8_bytes = &self.bytes;
+        let mut utf8_bytes = Vec::with_capacity(self.len());
+        utf8_bytes.extend_from_slice(&wtf8_bytes[..surrogate_pos]);
+        utf8_bytes.extend_from_slice(UTF8_REPLACEMENT_CHARACTER);
+        let mut pos = surrogate_pos + 3;
+        loop {
+            match self.next_surrogate(pos) {
+                Some((surrogate_pos, _)) => {
+                    utf8_bytes.extend_from_slice(&wtf8_bytes[pos..surrogate_pos]);
+                    utf8_bytes.extend_from_slice(UTF8_REPLACEMENT_CHARACTER);
+                    pos = surrogate_pos + 3;
+                }
+                None => {
+                    utf8_bytes.extend_from_slice(&wtf8_bytes[pos..]);
+                    return Cow::Owned(unsafe { String::from_utf8_unchecked(utf8_bytes) });
+                }
+            }
+        }
+    }
+
+    /// Converts the WTF-8 string to potentially ill-formed UTF-16
+    /// and return an iterator of 16-bit code units.
+    ///
+    /// This is lossless:
+    /// calling `Wtf8Buf::from_ill_formed_utf16` on the resulting code units
+    /// would always return the original WTF-8 string.
+    #[inline]
+    pub fn encode_wide(&self) -> EncodeWide {
+        EncodeWide {
+            code_points: self.code_points(),
+            extra: 0,
+        }
+    }
+
+    #[inline]
+    fn next_surrogate(&self, mut pos: usize) -> Option<(usize, u16)> {
+        let mut iter = self.bytes[pos..].iter();
+        loop {
+            let b = match iter.next() {
+                None => return None,
+                Some(&b) => b,
+            };
+            if b < 0x80 {
+                pos += 1;
+            } else if b < 0xE0 {
+                iter.next();
+                pos += 2;
+            } else if b == 0xED {
+                match (iter.next(), iter.next()) {
+                    (Some(&b2), Some(&b3)) if b2 >= 0xA0 => {
+                        return Some((pos, decode_surrogate(b2, b3)))
+                    }
+                    _ => pos += 3,
+                }
+            } else if b < 0xF0 {
+                iter.next();
+                iter.next();
+                pos += 3;
+            } else {
+                iter.next();
+                iter.next();
+                iter.next();
+                pos += 4;
+            }
+        }
+    }
+
+    #[inline]
+    fn final_lead_surrogate(&self) -> Option<u16> {
+        let len = self.len();
+        if len < 3 {
+            return None;
+        }
+        match &self.bytes[(len - 3)..] {
+            &[0xED, b2 @ 0xA0...0xAF, b3] => Some(decode_surrogate(b2, b3)),
+            _ => None,
+        }
+    }
+
+    #[inline]
+    fn initial_trail_surrogate(&self) -> Option<u16> {
+        let len = self.len();
+        if len < 3 {
+            return None;
+        }
+        match &self.bytes[..3] {
+            &[0xED, b2 @ 0xB0...0xBF, b3] => Some(decode_surrogate(b2, b3)),
+            _ => None,
+        }
+    }
+}
+
+
+/// Return a slice of the given string for the byte range [`begin`..`end`).
+///
+/// # Panics
+///
+/// Panics when `begin` and `end` do not point to code point boundaries,
+/// or point beyond the end of the string.
+impl ops::Index<ops::Range<usize>> for Wtf8 {
+    type Output = Wtf8;
+
+    #[inline]
+    fn index(&self, range: ops::Range<usize>) -> &Wtf8 {
+        // is_code_point_boundary checks that the index is in [0, .len()]
+        if range.start <= range.end && is_code_point_boundary(self, range.start) &&
+           is_code_point_boundary(self, range.end) {
+            unsafe { slice_unchecked(self, range.start, range.end) }
+        } else {
+            slice_error_fail(self, range.start, range.end)
+        }
+    }
+}
+
+/// Return a slice of the given string from byte `begin` to its end.
+///
+/// # Panics
+///
+/// Panics when `begin` is not at a code point boundary,
+/// or is beyond the end of the string.
+impl ops::Index<ops::RangeFrom<usize>> for Wtf8 {
+    type Output = Wtf8;
+
+    #[inline]
+    fn index(&self, range: ops::RangeFrom<usize>) -> &Wtf8 {
+        // is_code_point_boundary checks that the index is in [0, .len()]
+        if is_code_point_boundary(self, range.start) {
+            unsafe { slice_unchecked(self, range.start, self.len()) }
+        } else {
+            slice_error_fail(self, range.start, self.len())
+        }
+    }
+}
+
+/// Return a slice of the given string from its beginning to byte `end`.
+///
+/// # Panics
+///
+/// Panics when `end` is not at a code point boundary,
+/// or is beyond the end of the string.
+impl ops::Index<ops::RangeTo<usize>> for Wtf8 {
+    type Output = Wtf8;
+
+    #[inline]
+    fn index(&self, range: ops::RangeTo<usize>) -> &Wtf8 {
+        // is_code_point_boundary checks that the index is in [0, .len()]
+        if is_code_point_boundary(self, range.end) {
+            unsafe { slice_unchecked(self, 0, range.end) }
+        } else {
+            slice_error_fail(self, 0, range.end)
+        }
+    }
+}
+
+impl ops::Index<ops::RangeFull> for Wtf8 {
+    type Output = Wtf8;
+
+    #[inline]
+    fn index(&self, _range: ops::RangeFull) -> &Wtf8 {
+        self
+    }
+}
+
+#[inline]
+fn decode_surrogate(second_byte: u8, third_byte: u8) -> u16 {
+    // The first byte is assumed to be 0xED
+    0xD800 | (second_byte as u16 & 0x3F) << 6 | third_byte as u16 & 0x3F
+}
+
+#[inline]
+fn decode_surrogate_pair(lead: u16, trail: u16) -> char {
+    let code_point = 0x10000 + ((((lead - 0xD800) as u32) << 10) | (trail - 0xDC00) as u32);
+    unsafe { char::from_u32_unchecked(code_point) }
+}
+
+/// Copied from core::str::StrPrelude::is_char_boundary
+#[inline]
+pub fn is_code_point_boundary(slice: &Wtf8, index: usize) -> bool {
+    if index == slice.len() {
+        return true;
+    }
+    match slice.bytes.get(index) {
+        None => false,
+        Some(&b) => b < 128 || b >= 192,
+    }
+}
+
+/// Copied from core::str::raw::slice_unchecked
+#[inline]
+pub unsafe fn slice_unchecked(s: &Wtf8, begin: usize, end: usize) -> &Wtf8 {
+    // memory layout of an &[u8] and &Wtf8 are the same
+    Wtf8::from_bytes_unchecked(slice::from_raw_parts(s.bytes.as_ptr().offset(begin as isize),
+                                                     end - begin))
+}
+
+/// Copied from core::str::raw::slice_error_fail
+#[inline(never)]
+pub fn slice_error_fail(s: &Wtf8, begin: usize, end: usize) -> ! {
+    assert!(begin <= end);
+    panic!("index {} and/or {} in `{:?}` do not lie on character boundary",
+           begin,
+           end,
+           s);
+}
+
+/// Iterator for the code points of a WTF-8 string.
+///
+/// Created with the method `.code_points()`.
+#[derive(Clone)]
+pub struct Wtf8CodePoints<'a> {
+    bytes: slice::Iter<'a, u8>,
+}
+
+impl<'a> Iterator for Wtf8CodePoints<'a> {
+    type Item = CodePoint;
+
+    #[inline]
+    fn next(&mut self) -> Option<CodePoint> {
+        next_code_point(&mut self.bytes).map(|c| CodePoint { value: c })
+    }
+
+    #[inline]
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        let len = self.bytes.len();
+        (len.saturating_add(3) / 4, Some(len))
+    }
+}
+
+#[derive(Clone)]
+pub struct EncodeWide<'a> {
+    code_points: Wtf8CodePoints<'a>,
+    extra: u16,
+}
+
+// Copied from libunicode/u_str.rs
+impl<'a> Iterator for EncodeWide<'a> {
+    type Item = u16;
+
+    #[inline]
+    fn next(&mut self) -> Option<u16> {
+        if self.extra != 0 {
+            let tmp = self.extra;
+            self.extra = 0;
+            return Some(tmp);
+        }
+
+        self.code_points.next().map(|code_point| {
+            let n = unsafe { char::from_u32_unchecked(code_point.value).encode_utf16() };
+            let n = n.as_slice();
+            if n.len() == 2 {
+                self.extra = n[1];
+            }
+            n[0]
+        })
+    }
+
+    #[inline]
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        let (low, high) = self.code_points.size_hint();
+        // every code point gets either one u16 or two u16,
+        // so this iterator is between 1 or 2 times as
+        // long as the underlying iterator.
+        (low, high.and_then(|n| n.checked_mul(2)))
+    }
+}
+
+impl Hash for CodePoint {
+    #[inline]
+    fn hash<H: Hasher>(&self, state: &mut H) {
+        self.value.hash(state)
+    }
+}
+
+impl Hash for Wtf8Buf {
+    #[inline]
+    fn hash<H: Hasher>(&self, state: &mut H) {
+        state.write(&self.bytes);
+        0xfeu8.hash(state)
+    }
+}
+
+impl Hash for Wtf8 {
+    #[inline]
+    fn hash<H: Hasher>(&self, state: &mut H) {
+        state.write(&self.bytes);
+        0xfeu8.hash(state)
+    }
+}
+
+impl AsciiExt for Wtf8 {
+    type Owned = Wtf8Buf;
+
+    fn is_ascii(&self) -> bool {
+        self.bytes.is_ascii()
+    }
+    fn to_ascii_uppercase(&self) -> Wtf8Buf {
+        Wtf8Buf { bytes: self.bytes.to_ascii_uppercase() }
+    }
+    fn to_ascii_lowercase(&self) -> Wtf8Buf {
+        Wtf8Buf { bytes: self.bytes.to_ascii_lowercase() }
+    }
+    fn eq_ignore_ascii_case(&self, other: &Wtf8) -> bool {
+        self.bytes.eq_ignore_ascii_case(&other.bytes)
+    }
+
+    fn make_ascii_uppercase(&mut self) {
+        self.bytes.make_ascii_uppercase()
+    }
+    fn make_ascii_lowercase(&mut self) {
+        self.bytes.make_ascii_lowercase()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use collections::borrow::Cow;
+    use collections::{String, Vec};
+    use super::*;
+
+    #[test]
+    fn code_point_from_u32() {
+        assert!(CodePoint::from_u32(0).is_some());
+        assert!(CodePoint::from_u32(0xD800).is_some());
+        assert!(CodePoint::from_u32(0x10FFFF).is_some());
+        assert!(CodePoint::from_u32(0x110000).is_none());
+    }
+
+    #[test]
+    fn code_point_to_u32() {
+        fn c(value: u32) -> CodePoint {
+            CodePoint::from_u32(value).unwrap()
+        }
+        assert_eq!(c(0).to_u32(), 0);
+        assert_eq!(c(0xD800).to_u32(), 0xD800);
+        assert_eq!(c(0x10FFFF).to_u32(), 0x10FFFF);
+    }
+
+    #[test]
+    fn code_point_from_char() {
+        assert_eq!(CodePoint::from_char('a').to_u32(), 0x61);
+        assert_eq!(CodePoint::from_char('💩').to_u32(), 0x1F4A9);
+    }
+
+    #[test]
+    fn code_point_to_string() {
+        assert_eq!(format!("{:?}", CodePoint::from_char('a')), "U+0061");
+        assert_eq!(format!("{:?}", CodePoint::from_char('💩')), "U+1F4A9");
+    }
+
+    #[test]
+    fn code_point_to_char() {
+        fn c(value: u32) -> CodePoint {
+            CodePoint::from_u32(value).unwrap()
+        }
+        assert_eq!(c(0x61).to_char(), Some('a'));
+        assert_eq!(c(0x1F4A9).to_char(), Some('💩'));
+        assert_eq!(c(0xD800).to_char(), None);
+    }
+
+    #[test]
+    fn code_point_to_char_lossy() {
+        fn c(value: u32) -> CodePoint {
+            CodePoint::from_u32(value).unwrap()
+        }
+        assert_eq!(c(0x61).to_char_lossy(), 'a');
+        assert_eq!(c(0x1F4A9).to_char_lossy(), '💩');
+        assert_eq!(c(0xD800).to_char_lossy(), '\u{FFFD}');
+    }
+
+    #[test]
+    fn wtf8buf_new() {
+        assert_eq!(Wtf8Buf::new().bytes, b"");
+    }
+
+    #[test]
+    fn wtf8buf_from_str() {
+        assert_eq!(Wtf8Buf::from_str("").bytes, b"");
+        assert_eq!(Wtf8Buf::from_str("aé 💩").bytes,
+                   b"a\xC3\xA9 \xF0\x9F\x92\xA9");
+    }
+
+    #[test]
+    fn wtf8buf_from_string() {
+        assert_eq!(Wtf8Buf::from_string(String::from("")).bytes, b"");
+        assert_eq!(Wtf8Buf::from_string(String::from("aé 💩")).bytes,
+                   b"a\xC3\xA9 \xF0\x9F\x92\xA9");
+    }
+
+    #[test]
+    fn wtf8buf_from_wide() {
+        assert_eq!(Wtf8Buf::from_wide(&[]).bytes, b"");
+        assert_eq!(Wtf8Buf::from_wide(&[0x61, 0xE9, 0x20, 0xD83D, 0xD83D, 0xDCA9]).bytes,
+                   b"a\xC3\xA9 \xED\xA0\xBD\xF0\x9F\x92\xA9");
+    }
+
+    #[test]
+    fn wtf8buf_push_str() {
+        let mut string = Wtf8Buf::new();
+        assert_eq!(string.bytes, b"");
+        string.push_str("aé 💩");
+        assert_eq!(string.bytes, b"a\xC3\xA9 \xF0\x9F\x92\xA9");
+    }
+
+    #[test]
+    fn wtf8buf_push_char() {
+        let mut string = Wtf8Buf::from_str("aé ");
+        assert_eq!(string.bytes, b"a\xC3\xA9 ");
+        string.push_char('💩');
+        assert_eq!(string.bytes, b"a\xC3\xA9 \xF0\x9F\x92\xA9");
+    }
+
+    #[test]
+    fn wtf8buf_push() {
+        let mut string = Wtf8Buf::from_str("aé ");
+        assert_eq!(string.bytes, b"a\xC3\xA9 ");
+        string.push(CodePoint::from_char('💩'));
+        assert_eq!(string.bytes, b"a\xC3\xA9 \xF0\x9F\x92\xA9");
+
+        fn c(value: u32) -> CodePoint {
+            CodePoint::from_u32(value).unwrap()
+        }
+
+        let mut string = Wtf8Buf::new();
+        string.push(c(0xD83D));  // lead
+        string.push(c(0xDCA9));  // trail
+        assert_eq!(string.bytes, b"\xF0\x9F\x92\xA9");  // Magic!
+
+        let mut string = Wtf8Buf::new();
+        string.push(c(0xD83D));  // lead
+        string.push(c(0x20));  // not surrogate
+        string.push(c(0xDCA9));  // trail
+        assert_eq!(string.bytes, b"\xED\xA0\xBD \xED\xB2\xA9");
+
+        let mut string = Wtf8Buf::new();
+        string.push(c(0xD800));  // lead
+        string.push(c(0xDBFF));  // lead
+        assert_eq!(string.bytes, b"\xED\xA0\x80\xED\xAF\xBF");
+
+        let mut string = Wtf8Buf::new();
+        string.push(c(0xD800));  // lead
+        string.push(c(0xE000));  // not surrogate
+        assert_eq!(string.bytes, b"\xED\xA0\x80\xEE\x80\x80");
+
+        let mut string = Wtf8Buf::new();
+        string.push(c(0xD7FF));  // not surrogate
+        string.push(c(0xDC00));  // trail
+        assert_eq!(string.bytes, b"\xED\x9F\xBF\xED\xB0\x80");
+
+        let mut string = Wtf8Buf::new();
+        string.push(c(0x61));  // not surrogate, < 3 bytes
+        string.push(c(0xDC00));  // trail
+        assert_eq!(string.bytes, b"\x61\xED\xB0\x80");
+
+        let mut string = Wtf8Buf::new();
+        string.push(c(0xDC00));  // trail
+        assert_eq!(string.bytes, b"\xED\xB0\x80");
+    }
+
+    #[test]
+    fn wtf8buf_push_wtf8() {
+        let mut string = Wtf8Buf::from_str("aé");
+        assert_eq!(string.bytes, b"a\xC3\xA9");
+        string.push_wtf8(Wtf8::from_str(" 💩"));
+        assert_eq!(string.bytes, b"a\xC3\xA9 \xF0\x9F\x92\xA9");
+
+        fn w(v: &[u8]) -> &Wtf8 {
+            unsafe { Wtf8::from_bytes_unchecked(v) }
+        }
+
+        let mut string = Wtf8Buf::new();
+        string.push_wtf8(w(b"\xED\xA0\xBD"));  // lead
+        string.push_wtf8(w(b"\xED\xB2\xA9"));  // trail
+        assert_eq!(string.bytes, b"\xF0\x9F\x92\xA9");  // Magic!
+
+        let mut string = Wtf8Buf::new();
+        string.push_wtf8(w(b"\xED\xA0\xBD"));  // lead
+        string.push_wtf8(w(b" "));  // not surrogate
+        string.push_wtf8(w(b"\xED\xB2\xA9"));  // trail
+        assert_eq!(string.bytes, b"\xED\xA0\xBD \xED\xB2\xA9");
+
+        let mut string = Wtf8Buf::new();
+        string.push_wtf8(w(b"\xED\xA0\x80"));  // lead
+        string.push_wtf8(w(b"\xED\xAF\xBF"));  // lead
+        assert_eq!(string.bytes, b"\xED\xA0\x80\xED\xAF\xBF");
+
+        let mut string = Wtf8Buf::new();
+        string.push_wtf8(w(b"\xED\xA0\x80"));  // lead
+        string.push_wtf8(w(b"\xEE\x80\x80"));  // not surrogate
+        assert_eq!(string.bytes, b"\xED\xA0\x80\xEE\x80\x80");
+
+        let mut string = Wtf8Buf::new();
+        string.push_wtf8(w(b"\xED\x9F\xBF"));  // not surrogate
+        string.push_wtf8(w(b"\xED\xB0\x80"));  // trail
+        assert_eq!(string.bytes, b"\xED\x9F\xBF\xED\xB0\x80");
+
+        let mut string = Wtf8Buf::new();
+        string.push_wtf8(w(b"a"));  // not surrogate, < 3 bytes
+        string.push_wtf8(w(b"\xED\xB0\x80"));  // trail
+        assert_eq!(string.bytes, b"\x61\xED\xB0\x80");
+
+        let mut string = Wtf8Buf::new();
+        string.push_wtf8(w(b"\xED\xB0\x80"));  // trail
+        assert_eq!(string.bytes, b"\xED\xB0\x80");
+    }
+
+    #[test]
+    fn wtf8buf_truncate() {
+        let mut string = Wtf8Buf::from_str("aé");
+        string.truncate(1);
+        assert_eq!(string.bytes, b"a");
+    }
+
+    #[test]
+    #[should_panic]
+    fn wtf8buf_truncate_fail_code_point_boundary() {
+        let mut string = Wtf8Buf::from_str("aé");
+        string.truncate(2);
+    }
+
+    #[test]
+    #[should_panic]
+    fn wtf8buf_truncate_fail_longer() {
+        let mut string = Wtf8Buf::from_str("aé");
+        string.truncate(4);
+    }
+
+    #[test]
+    fn wtf8buf_into_string() {
+        let mut string = Wtf8Buf::from_str("aé 💩");
+        assert_eq!(string.clone().into_string(), Ok(String::from("aé 💩")));
+        string.push(CodePoint::from_u32(0xD800).unwrap());
+        assert_eq!(string.clone().into_string(), Err(string));
+    }
+
+    #[test]
+    fn wtf8buf_into_string_lossy() {
+        let mut string = Wtf8Buf::from_str("aé 💩");
+        assert_eq!(string.clone().into_string_lossy(), String::from("aé 💩"));
+        string.push(CodePoint::from_u32(0xD800).unwrap());
+        assert_eq!(string.clone().into_string_lossy(),
+                   String::from("aé 💩�"));
+    }
+
+    #[test]
+    fn wtf8buf_from_iterator() {
+        fn f(values: &[u32]) -> Wtf8Buf {
+            values.iter().map(|&c| CodePoint::from_u32(c).unwrap()).collect::<Wtf8Buf>()
+        }
+        assert_eq!(f(&[0x61, 0xE9, 0x20, 0x1F4A9]).bytes,
+                   b"a\xC3\xA9 \xF0\x9F\x92\xA9");
+
+        assert_eq!(f(&[0xD83D, 0xDCA9]).bytes, b"\xF0\x9F\x92\xA9");  // Magic!
+        assert_eq!(f(&[0xD83D, 0x20, 0xDCA9]).bytes,
+                   b"\xED\xA0\xBD \xED\xB2\xA9");
+        assert_eq!(f(&[0xD800, 0xDBFF]).bytes, b"\xED\xA0\x80\xED\xAF\xBF");
+        assert_eq!(f(&[0xD800, 0xE000]).bytes, b"\xED\xA0\x80\xEE\x80\x80");
+        assert_eq!(f(&[0xD7FF, 0xDC00]).bytes, b"\xED\x9F\xBF\xED\xB0\x80");
+        assert_eq!(f(&[0x61, 0xDC00]).bytes, b"\x61\xED\xB0\x80");
+        assert_eq!(f(&[0xDC00]).bytes, b"\xED\xB0\x80");
+    }
+
+    #[test]
+    fn wtf8buf_extend() {
+        fn e(initial: &[u32], extended: &[u32]) -> Wtf8Buf {
+            fn c(value: &u32) -> CodePoint {
+                CodePoint::from_u32(*value).unwrap()
+            }
+            let mut string = initial.iter().map(c).collect::<Wtf8Buf>();
+            string.extend(extended.iter().map(c));
+            string
+        }
+
+        assert_eq!(e(&[0x61, 0xE9], &[0x20, 0x1F4A9]).bytes,
+                   b"a\xC3\xA9 \xF0\x9F\x92\xA9");
+
+        assert_eq!(e(&[0xD83D], &[0xDCA9]).bytes, b"\xF0\x9F\x92\xA9");  // Magic!
+        assert_eq!(e(&[0xD83D, 0x20], &[0xDCA9]).bytes,
+                   b"\xED\xA0\xBD \xED\xB2\xA9");
+        assert_eq!(e(&[0xD800], &[0xDBFF]).bytes, b"\xED\xA0\x80\xED\xAF\xBF");
+        assert_eq!(e(&[0xD800], &[0xE000]).bytes, b"\xED\xA0\x80\xEE\x80\x80");
+        assert_eq!(e(&[0xD7FF], &[0xDC00]).bytes, b"\xED\x9F\xBF\xED\xB0\x80");
+        assert_eq!(e(&[0x61], &[0xDC00]).bytes, b"\x61\xED\xB0\x80");
+        assert_eq!(e(&[], &[0xDC00]).bytes, b"\xED\xB0\x80");
+    }
+
+    #[test]
+    fn wtf8buf_show() {
+        let mut string = Wtf8Buf::from_str("a\té \u{7f}💩\r");
+        string.push(CodePoint::from_u32(0xD800).unwrap());
+        assert_eq!(format!("{:?}", string),
+                   "\"a\\té \\u{7f}\u{1f4a9}\\r\\u{d800}\"");
+    }
+
+    #[test]
+    fn wtf8buf_as_slice() {
+        assert_eq!(Wtf8Buf::from_str("aé").as_slice(), Wtf8::from_str("aé"));
+    }
+
+    #[test]
+    fn wtf8buf_show_str() {
+        let text = "a\té 💩\r";
+        let string = Wtf8Buf::from_str(text);
+        assert_eq!(format!("{:?}", text), format!("{:?}", string));
+    }
+
+    #[test]
+    fn wtf8_from_str() {
+        assert_eq!(&Wtf8::from_str("").bytes, b"");
+        assert_eq!(&Wtf8::from_str("aé 💩").bytes,
+                   b"a\xC3\xA9 \xF0\x9F\x92\xA9");
+    }
+
+    #[test]
+    fn wtf8_len() {
+        assert_eq!(Wtf8::from_str("").len(), 0);
+        assert_eq!(Wtf8::from_str("aé 💩").len(), 8);
+    }
+
+    #[test]
+    fn wtf8_slice() {
+        assert_eq!(&Wtf8::from_str("aé 💩")[1..4].bytes, b"\xC3\xA9 ");
+    }
+
+    #[test]
+    #[should_panic]
+    fn wtf8_slice_not_code_point_boundary() {
+        &Wtf8::from_str("aé 💩")[2..4];
+    }
+
+    #[test]
+    fn wtf8_slice_from() {
+        assert_eq!(&Wtf8::from_str("aé 💩")[1..].bytes,
+                   b"\xC3\xA9 \xF0\x9F\x92\xA9");
+    }
+
+    #[test]
+    #[should_panic]
+    fn wtf8_slice_from_not_code_point_boundary() {
+        &Wtf8::from_str("aé 💩")[2..];
+    }
+
+    #[test]
+    fn wtf8_slice_to() {
+        assert_eq!(&Wtf8::from_str("aé 💩")[..4].bytes, b"a\xC3\xA9 ");
+    }
+
+    #[test]
+    #[should_panic]
+    fn wtf8_slice_to_not_code_point_boundary() {
+        &Wtf8::from_str("aé 💩")[5..];
+    }
+
+    #[test]
+    fn wtf8_ascii_byte_at() {
+        let slice = Wtf8::from_str("aé 💩");
+        assert_eq!(slice.ascii_byte_at(0), b'a');
+        assert_eq!(slice.ascii_byte_at(1), b'\xFF');
+        assert_eq!(slice.ascii_byte_at(2), b'\xFF');
+        assert_eq!(slice.ascii_byte_at(3), b' ');
+        assert_eq!(slice.ascii_byte_at(4), b'\xFF');
+    }
+
+    #[test]
+    fn wtf8_code_points() {
+        fn c(value: u32) -> CodePoint {
+            CodePoint::from_u32(value).unwrap()
+        }
+        fn cp(string: &Wtf8Buf) -> Vec<Option<char>> {
+            string.code_points().map(|c| c.to_char()).collect::<Vec<_>>()
+        }
+        let mut string = Wtf8Buf::from_str("é ");
+        assert_eq!(cp(&string), [Some('é'), Some(' ')]);
+        string.push(c(0xD83D));
+        assert_eq!(cp(&string), [Some('é'), Some(' '), None]);
+        string.push(c(0xDCA9));
+        assert_eq!(cp(&string), [Some('é'), Some(' '), Some('💩')]);
+    }
+
+    #[test]
+    fn wtf8_as_str() {
+        assert_eq!(Wtf8::from_str("").as_str(), Some(""));
+        assert_eq!(Wtf8::from_str("aé 💩").as_str(), Some("aé 💩"));
+        let mut string = Wtf8Buf::new();
+        string.push(CodePoint::from_u32(0xD800).unwrap());
+        assert_eq!(string.as_str(), None);
+    }
+
+    #[test]
+    fn wtf8_to_string_lossy() {
+        assert_eq!(Wtf8::from_str("").to_string_lossy(), Cow::Borrowed(""));
+        assert_eq!(Wtf8::from_str("aé 💩").to_string_lossy(),
+                   Cow::Borrowed("aé 💩"));
+        let mut string = Wtf8Buf::from_str("aé 💩");
+        string.push(CodePoint::from_u32(0xD800).unwrap());
+        let expected: Cow<str> = Cow::Owned(String::from("aé 💩�"));
+        assert_eq!(string.to_string_lossy(), expected);
+    }
+
+    #[test]
+    fn wtf8_encode_wide() {
+        let mut string = Wtf8Buf::from_str("aé ");
+        string.push(CodePoint::from_u32(0xD83D).unwrap());
+        string.push_char('💩');
+        assert_eq!(string.encode_wide().collect::<Vec<_>>(),
+                   vec![0x61, 0xE9, 0x20, 0xD83D, 0xD83D, 0xDCA9]);
+    }
+}