//! Kernel mode string types.

use ::NTSTATUS;

/// NT native string types.
pub trait NativeString {
	/// Size of string in bytes.
	fn size(&self) -> u16;
	/// Size of buffer in bytes.
	fn max_size(&self) -> u16;

	/// Check is the string is empty.
	fn is_empty(&self) -> bool {
		self.size() == 0u16
	}
}

/// A counted Unicode string.
#[repr(C)]
pub struct UNICODE_STRING
{
	/// The length in **bytes** of the string stored in `Buffer`.
	pub Length: u16,
	/// The length in **bytes** of `Buffer`.
	pub MaximumLength: u16,
	/// Pointer to a buffer used to contain a string of wide characters.
	pub Buffer: *const u16,
}

/// A counted string used for ANSI strings.
#[repr(C)]
pub struct ANSI_STRING
{
	/// The length in *bytes* of the string stored in `Buffer`.
	pub Length: u16,
	/// The length in bytes of `Buffer`.
	pub MaximumLength: u16,
	/// Pointer to a buffer used to contain a string of characters.
	pub Buffer: *const u8,
}

impl NativeString for UNICODE_STRING
{
	fn size(&self) -> u16 { self.Length }
	fn max_size(&self) -> u16 { self.MaximumLength }
}

impl UNICODE_STRING
{
}

/// Initializes a counted Unicode string.
impl Default for UNICODE_STRING {
	fn default() -> Self {
		UNICODE_STRING { Length: 0, MaximumLength: 0, Buffer: ::core::ptr::null() }
	}
}

impl<'a> From<&'a [u8]> for ANSI_STRING {
	fn from(s: &'a [u8]) -> Self {
		let len = s.len();
		let n = if len > 0 && s[len-1] == 0 { len - 1 } else { len };
		ANSI_STRING { Length: n as u16, MaximumLength: len as u16, Buffer: s.as_ptr() }
	}
}


pub type AnsiString = ANSI_STRING;
pub type UnicodeString = UNICODE_STRING;
pub type CONST_UNICODE_STRING = UNICODE_STRING;
pub type CONST_ANSI_STRING = ANSI_STRING;

pub type PUNICODE_STRING = *mut UNICODE_STRING;
pub type PCUNICODE_STRING = *const UNICODE_STRING;

extern "system"
{
	pub fn RtlIntegerToUnicodeString(Value: u32, Base: u32, String: &mut UNICODE_STRING) -> NTSTATUS;
	pub fn RtlInt64ToUnicodeString(Value: u64, Base: u32, String: &mut UNICODE_STRING) -> NTSTATUS;
	pub fn RtlUnicodeStringToInteger(String: &CONST_UNICODE_STRING, Base: u32, Value: &mut u32) -> NTSTATUS;

	pub fn RtlUnicodeStringToAnsiString(DestinationString: &mut ANSI_STRING, SourceString: &CONST_UNICODE_STRING, AllocateDestination: bool) -> NTSTATUS;
	pub fn RtlUnicodeStringToAnsiSize(SourceString: &CONST_UNICODE_STRING) -> u32;

	pub fn RtlAnsiStringToUnicodeString(DestinationString: &mut UNICODE_STRING, SourceString: &CONST_ANSI_STRING, AllocateDestination: bool) -> NTSTATUS;
	pub fn RtlAnsiStringToUnicodeSize(SourceString: &CONST_ANSI_STRING) -> u32;

	pub fn RtlCompareUnicodeString (String1: &CONST_UNICODE_STRING, String2: &CONST_UNICODE_STRING, CaseInSensitive: bool) -> i32;
	pub fn RtlCompareString (String1: &CONST_ANSI_STRING, String2: &CONST_ANSI_STRING, CaseInSensitive: bool) -> i32;

	pub fn RtlEqualUnicodeString(String1: &CONST_UNICODE_STRING, String2: &CONST_UNICODE_STRING) -> bool;
	pub fn RtlEqualString(String1: &CONST_ANSI_STRING, String2: &CONST_ANSI_STRING) -> bool;

	pub fn RtlFreeAnsiString(UnicodeString: &mut ANSI_STRING);
	pub fn RtlFreeUnicodeString(UnicodeString: &mut UNICODE_STRING);
}