Merge pull request #18 from FenrirWolf/time

ctr-std: add time module

2 files changed, 346 insertions, 2 deletions

diff --git a/ctr-std/src/sys/unix/mod.rs b/ctr-std/src/sys/unix/mod.rs
index 5ea31af..ec657d8 100644
--- a/ctr-std/src/sys/unix/mod.rs
+++ b/ctr-std/src/sys/unix/mod.rs
@@ -10,6 +10,9 @@
 
 #![allow(missing_docs, bad_style)]
 
+use io::{self, ErrorKind};
+use libc;
+
 pub mod ext;
 pub mod fast_thread_local;
 pub mod memchr;
@@ -18,9 +21,45 @@ pub mod os;
 pub mod os_str;
 pub mod path;
 pub mod thread_local;
+pub mod time;
 
-use io::ErrorKind;
-use libc;
+#[cfg(not(test))]
+pub fn init() {
+    use alloc::oom;
+
+    // By default, some platforms will send a *signal* when an EPIPE error
+    // would otherwise be delivered. This runtime doesn't install a SIGPIPE
+    // handler, causing it to kill the program, which isn't exactly what we
+    // want!
+    //
+    // Hence, we set SIGPIPE to ignore when the program starts up in order
+    // to prevent this problem.
+    unsafe {
+        reset_sigpipe();
+    }
+
+    oom::set_oom_handler(oom_handler);
+
+    // A nicer handler for out-of-memory situations than the default one. This
+    // one prints a message to stderr before aborting. It is critical that this
+    // code does not allocate any memory since we are in an OOM situation. Any
+    // errors are ignored while printing since there's nothing we can do about
+    // them and we are about to exit anyways.
+    fn oom_handler() -> ! {
+        use intrinsics;
+        let msg = "fatal runtime error: out of memory\n";
+        unsafe {
+            libc::write(libc::STDERR_FILENO,
+                        msg.as_ptr() as *const libc::c_void,
+                        msg.len());
+            intrinsics::abort();
+        }
+    }
+
+	// I don't think we have signal handling on the 3DS, so let's leave this
+	// blank for now
+    unsafe fn reset_sigpipe() {}
+}
 
 pub fn decode_error_kind(errno: i32) -> ErrorKind {
     match errno as libc::c_int {
@@ -48,6 +87,41 @@ pub fn decode_error_kind(errno: i32) -> ErrorKind {
     }
 }
 
+#[doc(hidden)]
+pub trait IsMinusOne {
+    fn is_minus_one(&self) -> bool;
+}
+
+macro_rules! impl_is_minus_one {
+    ($($t:ident)*) => ($(impl IsMinusOne for $t {
+        fn is_minus_one(&self) -> bool {
+            *self == -1
+        }
+    })*)
+}
+
+impl_is_minus_one! { i8 i16 i32 i64 isize }
+
+pub fn cvt<T: IsMinusOne>(t: T) -> io::Result<T> {
+    if t.is_minus_one() {
+        Err(io::Error::last_os_error())
+    } else {
+        Ok(t)
+    }
+}
+
+pub fn cvt_r<T, F>(mut f: F) -> io::Result<T>
+    where T: IsMinusOne,
+          F: FnMut() -> T
+{
+    loop {
+        match cvt(f()) {
+            Err(ref e) if e.kind() == ErrorKind::Interrupted => {}
+            other => return other,
+        }
+    }
+}
+
 pub unsafe fn abort_internal() -> ! {
     ::libc::abort()
 }
diff --git a/ctr-std/src/sys/unix/time.rs b/ctr-std/src/sys/unix/time.rs
new file mode 100644
index 0000000..052bd32
--- /dev/null
+++ b/ctr-std/src/sys/unix/time.rs
@@ -0,0 +1,270 @@
+// 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 cmp::Ordering;
+use libc;
+use time::Duration;
+
+pub use self::inner::{Instant, SystemTime, UNIX_EPOCH};
+
+const NSEC_PER_SEC: u64 = 1_000_000_000;
+
+#[derive(Copy, Clone)]
+struct Timespec {
+    t: libc::timespec,
+}
+
+impl Timespec {
+    fn sub_timespec(&self, other: &Timespec) -> Result<Duration, Duration> {
+        if self >= other {
+            Ok(if self.t.tv_nsec >= other.t.tv_nsec {
+                Duration::new((self.t.tv_sec - other.t.tv_sec) as u64,
+                              (self.t.tv_nsec - other.t.tv_nsec) as u32)
+            } else {
+                Duration::new((self.t.tv_sec - 1 - other.t.tv_sec) as u64,
+                              self.t.tv_nsec as u32 + (NSEC_PER_SEC as u32) -
+                              other.t.tv_nsec as u32)
+            })
+        } else {
+            match other.sub_timespec(self) {
+                Ok(d) => Err(d),
+                Err(d) => Ok(d),
+            }
+        }
+    }
+
+    fn add_duration(&self, other: &Duration) -> Timespec {
+        let secs = (self.t.tv_sec as i64).checked_add(other.as_secs() as i64);
+        let mut secs = secs.expect("overflow when adding duration to time");
+
+        // Nano calculations can't overflow because nanos are <1B which fit
+        // in a u32.
+        let mut nsec = other.subsec_nanos() + self.t.tv_nsec as u32;
+        if nsec >= NSEC_PER_SEC as u32 {
+            nsec -= NSEC_PER_SEC as u32;
+            secs = secs.checked_add(1).expect("overflow when adding \
+                                               duration to time");
+        }
+        Timespec {
+            t: libc::timespec {
+                tv_sec: secs as libc::time_t,
+                tv_nsec: nsec as libc::c_long,
+            },
+        }
+    }
+
+    fn sub_duration(&self, other: &Duration) -> Timespec {
+        let secs = (self.t.tv_sec as i64).checked_sub(other.as_secs() as i64);
+        let mut secs = secs.expect("overflow when subtracting duration \
+                                    from time");
+
+        // Similar to above, nanos can't overflow.
+        let mut nsec = self.t.tv_nsec as i32 - other.subsec_nanos() as i32;
+        if nsec < 0 {
+            nsec += NSEC_PER_SEC as i32;
+            secs = secs.checked_sub(1).expect("overflow when subtracting \
+                                               duration from time");
+        }
+        Timespec {
+            t: libc::timespec {
+                tv_sec: secs as libc::time_t,
+                tv_nsec: nsec as libc::c_long,
+            },
+        }
+    }
+}
+
+impl PartialEq for Timespec {
+    fn eq(&self, other: &Timespec) -> bool {
+        self.t.tv_sec == other.t.tv_sec && self.t.tv_nsec == other.t.tv_nsec
+    }
+}
+
+impl Eq for Timespec {}
+
+impl PartialOrd for Timespec {
+    fn partial_cmp(&self, other: &Timespec) -> Option<Ordering> {
+        Some(self.cmp(other))
+    }
+}
+
+impl Ord for Timespec {
+    fn cmp(&self, other: &Timespec) -> Ordering {
+        let me = (self.t.tv_sec, self.t.tv_nsec);
+        let other = (other.t.tv_sec, other.t.tv_nsec);
+        me.cmp(&other)
+    }
+}
+
+mod inner {
+    use fmt;
+    use libc;
+    use sys::cvt;
+    use sys_common::mul_div_u64;
+    use time::Duration;
+
+    use super::NSEC_PER_SEC;
+    use super::Timespec;
+
+    use spin;
+    use libctru;
+
+    #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Debug)]
+    pub struct Instant {
+        t: u64
+    }
+
+    #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord)]
+    pub struct SystemTime {
+        t: Timespec,
+    }
+
+    pub const UNIX_EPOCH: SystemTime = SystemTime {
+        t: Timespec {
+            t: libc::timespec {
+                tv_sec: 0,
+                tv_nsec: 0,
+            },
+        },
+    };
+
+    impl Instant {
+        pub fn now() -> Instant {
+            Instant { t: ctr_absolute_time() }
+        }
+
+        pub fn sub_instant(&self, other: &Instant) -> Duration {
+            let info = info();
+            let diff = self.t.checked_sub(other.t)
+                           .expect("second instant is later than self");
+            let nanos = mul_div_u64(diff, info.numer as u64, info.denom as u64);
+            Duration::new(nanos / NSEC_PER_SEC, (nanos % NSEC_PER_SEC) as u32)
+        }
+
+        pub fn add_duration(&self, other: &Duration) -> Instant {
+            Instant {
+                t: self.t.checked_add(dur2intervals(other))
+                       .expect("overflow when adding duration to instant"),
+            }
+        }
+
+        pub fn sub_duration(&self, other: &Duration) -> Instant {
+            Instant {
+                t: self.t.checked_sub(dur2intervals(other))
+                       .expect("overflow when adding duration to instant"),
+            }
+        }
+    }
+
+    // The initial system tick after which all Instants occur
+    static TICK: spin::Once<u64> = spin::Once::new();
+
+    // A source of monotonic time based on ticks of the 3DS CPU. Returns the
+    // number of system ticks elapsed since an arbitrary point in the past
+    fn ctr_absolute_time() -> u64 {
+        let first_tick = get_first_tick();
+        let current_tick = get_system_tick();
+        current_tick - first_tick
+    }
+
+    // The first time this function is called, it generates and returns the
+    // initial system tick used to create Instants
+    //
+    // subsequent calls to this function return the previously generated
+    // tick value
+    fn get_first_tick() -> u64 {
+        *TICK.call_once(get_system_tick)
+    }
+
+    // Gets the current system tick
+    #[inline]
+    fn get_system_tick() -> u64 {
+        unsafe { libctru::svc::svcGetSystemTick() }
+    }
+
+    // A struct representing the clock speed of the 3DS
+    struct CtrClockInfo {
+        numer: u32,
+        denom: u32,
+    }
+
+    // Initializes the CtrClockInfo struct
+    //
+    // Note that svcGetSystemTick always runs at 268MHz (268,111,856Hz), even
+    // on a New 3DS running in 804MHz mode
+    //
+    // See https://www.3dbrew.org/wiki/Hardware#Common_hardware
+    fn info() -> CtrClockInfo {
+        CtrClockInfo {
+            numer: 1_000_000_000,
+            denom: 268_111_856,
+        }
+    }
+
+    fn dur2intervals(dur: &Duration) -> u64 {
+        let info = info();
+        let nanos = dur.as_secs().checked_mul(NSEC_PER_SEC).and_then(|nanos| {
+            nanos.checked_add(dur.subsec_nanos() as u64)
+        }).expect("overflow converting duration to nanoseconds");
+        mul_div_u64(nanos, info.denom as u64, info.numer as u64)
+    }
+
+    impl SystemTime {
+        pub fn now() -> SystemTime {
+            use ptr;
+
+            let mut s = libc::timeval {
+                tv_sec: 0,
+                tv_usec: 0,
+            };
+            cvt(unsafe {
+                libc::gettimeofday(&mut s, ptr::null_mut())
+            }).unwrap();
+            return SystemTime::from(s)
+        }
+
+        pub fn sub_time(&self, other: &SystemTime)
+                        -> Result<Duration, Duration> {
+            self.t.sub_timespec(&other.t)
+        }
+
+        pub fn add_duration(&self, other: &Duration) -> SystemTime {
+            SystemTime { t: self.t.add_duration(other) }
+        }
+
+        pub fn sub_duration(&self, other: &Duration) -> SystemTime {
+            SystemTime { t: self.t.sub_duration(other) }
+        }
+    }
+
+    impl From<libc::timeval> for SystemTime {
+        fn from(t: libc::timeval) -> SystemTime {
+            SystemTime::from(libc::timespec {
+                tv_sec: t.tv_sec,
+                tv_nsec: (t.tv_usec * 1000) as libc::c_long,
+            })
+        }
+    }
+
+    impl From<libc::timespec> for SystemTime {
+        fn from(t: libc::timespec) -> SystemTime {
+            SystemTime { t: Timespec { t: t } }
+        }
+    }
+
+    impl fmt::Debug for SystemTime {
+        fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+            f.debug_struct("SystemTime")
+             .field("tv_sec", &self.t.t.tv_sec)
+             .field("tv_nsec", &self.t.t.tv_nsec)
+             .finish()
+        }
+    }
+}