blob: a25bab6e0f92830e757aa0c08bfedfdac9f5b8ea [file] [log] [blame]
/*!
This crate provides convenience methods for encoding and decoding numbers
in either big-endian or little-endian order.
The organization of the crate is pretty simple. A trait, `ByteOrder`, specifies
byte conversion methods for each type of number in Rust (sans numbers that have
a platform dependent size like `usize` and `isize`). Two types, `BigEndian`
and `LittleEndian` implement these methods. Finally, `ReadBytesExt` and
`WriteBytesExt` provide convenience methods available to all types that
implement `Read` and `Write`.
# Examples
Read unsigned 16 bit big-endian integers from a `Read` type:
```rust
use std::io::Cursor;
use byteorder::{BigEndian, ReadBytesExt};
let mut rdr = Cursor::new(vec![2, 5, 3, 0]);
// Note that we use type parameters to indicate which kind of byte order
// we want!
assert_eq!(517, rdr.read_u16::<BigEndian>().unwrap());
assert_eq!(768, rdr.read_u16::<BigEndian>().unwrap());
```
Write unsigned 16 bit little-endian integers to a `Write` type:
```rust
use byteorder::{LittleEndian, WriteBytesExt};
let mut wtr = vec![];
wtr.write_u16::<LittleEndian>(517).unwrap();
wtr.write_u16::<LittleEndian>(768).unwrap();
assert_eq!(wtr, vec![5, 2, 0, 3]);
```
*/
#![crate_name = "byteorder"]
#![doc(html_root_url = "http://burntsushi.net/rustdoc/byteorder")]
#![cfg_attr(not(feature = "std"), no_std)]
#![deny(missing_docs)]
#[cfg(feature = "std")]
extern crate core;
use core::mem::transmute;
use core::ptr::copy_nonoverlapping;
#[cfg(feature = "std")]
pub use new::{ReadBytesExt, WriteBytesExt};
#[cfg(feature = "std")]
mod new;
#[inline]
fn extend_sign(val: u64, nbytes: usize) -> i64 {
let shift = (8 - nbytes) * 8;
(val << shift) as i64 >> shift
}
#[inline]
fn unextend_sign(val: i64, nbytes: usize) -> u64 {
let shift = (8 - nbytes) * 8;
(val << shift) as u64 >> shift
}
#[inline]
fn pack_size(n: u64) -> usize {
if n < 1 << 8 {
1
} else if n < 1 << 16 {
2
} else if n < 1 << 24 {
3
} else if n < 1 << 32 {
4
} else if n < 1 << 40 {
5
} else if n < 1 << 48 {
6
} else if n < 1 << 56 {
7
} else {
8
}
}
/// ByteOrder describes types that can serialize integers as bytes.
///
/// Note that `Self` does not appear anywhere in this trait's definition!
/// Therefore, in order to use it, you'll need to use syntax like
/// `T::read_u16(&[0, 1])` where `T` implements `ByteOrder`.
///
/// This crate provides two types that implement `ByteOrder`: `BigEndian`
/// and `LittleEndian`.
///
/// # Examples
///
/// Write and read `u32` numbers in little endian order:
///
/// ```rust
/// use byteorder::{ByteOrder, LittleEndian};
///
/// let mut buf = [0; 4];
/// LittleEndian::write_u32(&mut buf, 1_000_000);
/// assert_eq!(1_000_000, LittleEndian::read_u32(&buf));
/// ```
///
/// Write and read `i16` numbers in big endian order:
///
/// ```rust
/// use byteorder::{ByteOrder, BigEndian};
///
/// let mut buf = [0; 2];
/// BigEndian::write_i16(&mut buf, -50_000);
/// assert_eq!(-50_000, BigEndian::read_i16(&buf));
/// ```
pub trait ByteOrder {
/// Reads an unsigned 16 bit integer from `buf`.
///
/// Panics when `buf.len() < 2`.
fn read_u16(buf: &[u8]) -> u16;
/// Reads an unsigned 32 bit integer from `buf`.
///
/// Panics when `buf.len() < 4`.
fn read_u32(buf: &[u8]) -> u32;
/// Reads an unsigned 64 bit integer from `buf`.
///
/// Panics when `buf.len() < 8`.
fn read_u64(buf: &[u8]) -> u64;
/// Reads an unsigned n-bytes integer from `buf`.
///
/// Panics when `nbytes < 1` or `nbytes > 8` or
/// `buf.len() < nbytes`
fn read_uint(buf: &[u8], nbytes: usize) -> u64;
/// Writes an unsigned 16 bit integer `n` to `buf`.
///
/// Panics when `buf.len() < 2`.
fn write_u16(buf: &mut [u8], n: u16);
/// Writes an unsigned 32 bit integer `n` to `buf`.
///
/// Panics when `buf.len() < 4`.
fn write_u32(buf: &mut [u8], n: u32);
/// Writes an unsigned 64 bit integer `n` to `buf`.
///
/// Panics when `buf.len() < 8`.
fn write_u64(buf: &mut [u8], n: u64);
/// Writes an unsigned integer `n` to `buf` using only `nbytes`.
///
/// If `n` is not representable in `nbytes`, or if `nbytes` is `> 8`, then
/// this method panics.
fn write_uint(buf: &mut [u8], n: u64, nbytes: usize);
/// Reads a signed 16 bit integer from `buf`.
///
/// Panics when `buf.len() < 2`.
#[inline]
fn read_i16(buf: &[u8]) -> i16 {
Self::read_u16(buf) as i16
}
/// Reads a signed 32 bit integer from `buf`.
///
/// Panics when `buf.len() < 4`.
#[inline]
fn read_i32(buf: &[u8]) -> i32 {
Self::read_u32(buf) as i32
}
/// Reads a signed 64 bit integer from `buf`.
///
/// Panics when `buf.len() < 8`.
#[inline]
fn read_i64(buf: &[u8]) -> i64 {
Self::read_u64(buf) as i64
}
/// Reads a signed n-bytes integer from `buf`.
///
/// Panics when `nbytes < 1` or `nbytes > 8` or
/// `buf.len() < nbytes`
#[inline]
fn read_int(buf: &[u8], nbytes: usize) -> i64 {
extend_sign(Self::read_uint(buf, nbytes), nbytes)
}
/// Reads a IEEE754 single-precision (4 bytes) floating point number.
///
/// Panics when `buf.len() < 4`.
#[inline]
fn read_f32(buf: &[u8]) -> f32 {
unsafe { transmute(Self::read_u32(buf)) }
}
/// Reads a IEEE754 double-precision (8 bytes) floating point number.
///
/// Panics when `buf.len() < 8`.
#[inline]
fn read_f64(buf: &[u8]) -> f64 {
unsafe { transmute(Self::read_u64(buf)) }
}
/// Writes a signed 16 bit integer `n` to `buf`.
///
/// Panics when `buf.len() < 2`.
#[inline]
fn write_i16(buf: &mut [u8], n: i16) {
Self::write_u16(buf, n as u16)
}
/// Writes a signed 32 bit integer `n` to `buf`.
///
/// Panics when `buf.len() < 4`.
#[inline]
fn write_i32(buf: &mut [u8], n: i32) {
Self::write_u32(buf, n as u32)
}
/// Writes a signed 64 bit integer `n` to `buf`.
///
/// Panics when `buf.len() < 8`.
#[inline]
fn write_i64(buf: &mut [u8], n: i64) {
Self::write_u64(buf, n as u64)
}
/// Writes a signed integer `n` to `buf` using only `nbytes`.
///
/// If `n` is not representable in `nbytes`, or if `nbytes` is `> 8`, then
/// this method panics.
#[inline]
fn write_int(buf: &mut [u8], n: i64, nbytes: usize) {
Self::write_uint(buf, unextend_sign(n, nbytes), nbytes)
}
/// Writes a IEEE754 single-precision (4 bytes) floating point number.
///
/// Panics when `buf.len() < 4`.
#[inline]
fn write_f32(buf: &mut [u8], n: f32) {
Self::write_u32(buf, unsafe { transmute(n) })
}
/// Writes a IEEE754 double-precision (8 bytes) floating point number.
///
/// Panics when `buf.len() < 8`.
#[inline]
fn write_f64(buf: &mut [u8], n: f64) {
Self::write_u64(buf, unsafe { transmute(n) })
}
}
/// Defines big-endian serialization.
///
/// Note that this type has no value constructor. It is used purely at the
/// type level.
#[allow(missing_copy_implementations)] pub enum BigEndian {}
/// Defines little-endian serialization.
///
/// Note that this type has no value constructor. It is used purely at the
/// type level.
#[allow(missing_copy_implementations)] pub enum LittleEndian {}
/// Defines network byte order serialization.
///
/// Network byte order is defined by [RFC 1700][1] to be big-endian, and is
/// referred to in several protocol specifications. This type is an alias of
/// BigEndian.
///
/// [1]: https://tools.ietf.org/html/rfc1700
///
/// Note that this type has no value constructor. It is used purely at the
/// type level.
pub type NetworkEndian = BigEndian;
/// Defines system native-endian serialization.
///
/// Note that this type has no value constructor. It is used purely at the
/// type level.
#[cfg(target_endian = "little")]
pub type NativeEndian = LittleEndian;
/// Defines system native-endian serialization.
///
/// Note that this type has no value constructor. It is used purely at the
/// type level.
#[cfg(target_endian = "big")]
pub type NativeEndian = BigEndian;
macro_rules! read_num_bytes {
($ty:ty, $size:expr, $src:expr, $which:ident) => ({
assert!($size == ::core::mem::size_of::<$ty>());
assert!($size <= $src.len());
let mut data: $ty = 0;
unsafe {
copy_nonoverlapping(
$src.as_ptr(),
&mut data as *mut $ty as *mut u8,
$size);
}
data.$which()
});
}
macro_rules! write_num_bytes {
($ty:ty, $size:expr, $n:expr, $dst:expr, $which:ident) => ({
assert!($size <= $dst.len());
unsafe {
// N.B. https://github.com/rust-lang/rust/issues/22776
let bytes = transmute::<_, [u8; $size]>($n.$which());
copy_nonoverlapping((&bytes).as_ptr(), $dst.as_mut_ptr(), $size);
}
});
}
impl ByteOrder for BigEndian {
#[inline]
fn read_u16(buf: &[u8]) -> u16 {
read_num_bytes!(u16, 2, buf, to_be)
}
#[inline]
fn read_u32(buf: &[u8]) -> u32 {
read_num_bytes!(u32, 4, buf, to_be)
}
#[inline]
fn read_u64(buf: &[u8]) -> u64 {
read_num_bytes!(u64, 8, buf, to_be)
}
#[inline]
fn read_uint(buf: &[u8], nbytes: usize) -> u64 {
assert!(1 <= nbytes && nbytes <= 8 && nbytes <= buf.len());
let mut out = [0u8; 8];
let ptr_out = out.as_mut_ptr();
unsafe {
copy_nonoverlapping(
buf.as_ptr(), ptr_out.offset((8 - nbytes) as isize), nbytes);
(*(ptr_out as *const u64)).to_be()
}
}
#[inline]
fn write_u16(buf: &mut [u8], n: u16) {
write_num_bytes!(u16, 2, n, buf, to_be);
}
#[inline]
fn write_u32(buf: &mut [u8], n: u32) {
write_num_bytes!(u32, 4, n, buf, to_be);
}
#[inline]
fn write_u64(buf: &mut [u8], n: u64) {
write_num_bytes!(u64, 8, n, buf, to_be);
}
#[inline]
fn write_uint(buf: &mut [u8], n: u64, nbytes: usize) {
assert!(pack_size(n) <= nbytes && nbytes <= 8);
assert!(nbytes <= buf.len());
unsafe {
let bytes: [u8; 8] = transmute(n.to_be());
copy_nonoverlapping(
bytes.as_ptr().offset((8 - nbytes) as isize),
buf.as_mut_ptr(),
nbytes);
}
}
}
impl ByteOrder for LittleEndian {
#[inline]
fn read_u16(buf: &[u8]) -> u16 {
read_num_bytes!(u16, 2, buf, to_le)
}
#[inline]
fn read_u32(buf: &[u8]) -> u32 {
read_num_bytes!(u32, 4, buf, to_le)
}
#[inline]
fn read_u64(buf: &[u8]) -> u64 {
read_num_bytes!(u64, 8, buf, to_le)
}
#[inline]
fn read_uint(buf: &[u8], nbytes: usize) -> u64 {
assert!(1 <= nbytes && nbytes <= 8 && nbytes <= buf.len());
let mut out = [0u8; 8];
let ptr_out = out.as_mut_ptr();
unsafe {
copy_nonoverlapping(buf.as_ptr(), ptr_out, nbytes);
(*(ptr_out as *const u64)).to_le()
}
}
#[inline]
fn write_u16(buf: &mut [u8], n: u16) {
write_num_bytes!(u16, 2, n, buf, to_le);
}
#[inline]
fn write_u32(buf: &mut [u8], n: u32) {
write_num_bytes!(u32, 4, n, buf, to_le);
}
#[inline]
fn write_u64(buf: &mut [u8], n: u64) {
write_num_bytes!(u64, 8, n, buf, to_le);
}
#[inline]
fn write_uint(buf: &mut [u8], n: u64, nbytes: usize) {
assert!(pack_size(n as u64) <= nbytes && nbytes <= 8);
assert!(nbytes <= buf.len());
unsafe {
let bytes: [u8; 8] = transmute(n.to_le());
copy_nonoverlapping(bytes.as_ptr(), buf.as_mut_ptr(), nbytes);
}
}
}
#[cfg(test)]
mod test {
extern crate quickcheck;
extern crate rand;
use test::rand::thread_rng;
use test::quickcheck::{QuickCheck, StdGen, Testable};
const U64_MAX: u64 = ::std::u64::MAX;
const I64_MAX: u64 = ::std::i64::MAX as u64;
fn qc_sized<A: Testable>(f: A, size: u64) {
QuickCheck::new()
.gen(StdGen::new(thread_rng(), size as usize))
.tests(1_00)
.max_tests(10_000)
.quickcheck(f);
}
macro_rules! qc_byte_order {
($name:ident, $ty_int:ident, $max:expr,
$bytes:expr, $read:ident, $write:ident) => (
mod $name {
use {BigEndian, ByteOrder, NativeEndian, LittleEndian};
use super::qc_sized;
#[test]
fn big_endian() {
let max = ($max - 1) >> (8 * (8 - $bytes));
fn prop(n: $ty_int) -> bool {
let mut buf = [0; 8];
BigEndian::$write(&mut buf, n, $bytes);
n == BigEndian::$read(&mut buf[..$bytes], $bytes)
}
qc_sized(prop as fn($ty_int) -> bool, max);
}
#[test]
fn little_endian() {
let max = ($max - 1) >> (8 * (8 - $bytes));
fn prop(n: $ty_int) -> bool {
let mut buf = [0; 8];
LittleEndian::$write(&mut buf, n, $bytes);
n == LittleEndian::$read(&mut buf[..$bytes], $bytes)
}
qc_sized(prop as fn($ty_int) -> bool, max);
}
#[test]
fn native_endian() {
let max = ($max - 1) >> (8 * (8 - $bytes));
fn prop(n: $ty_int) -> bool {
let mut buf = [0; 8];
NativeEndian::$write(&mut buf, n, $bytes);
n == NativeEndian::$read(&mut buf[..$bytes], $bytes)
}
qc_sized(prop as fn($ty_int) -> bool, max);
}
}
);
($name:ident, $ty_int:ident, $max:expr,
$read:ident, $write:ident) => (
mod $name {
use std::mem::size_of;
use {BigEndian, ByteOrder, NativeEndian, LittleEndian};
use super::qc_sized;
#[test]
fn big_endian() {
fn prop(n: $ty_int) -> bool {
let bytes = size_of::<$ty_int>();
let mut buf = [0; 8];
BigEndian::$write(&mut buf[8 - bytes..], n);
n == BigEndian::$read(&mut buf[8 - bytes..])
}
qc_sized(prop as fn($ty_int) -> bool, $max - 1);
}
#[test]
fn little_endian() {
fn prop(n: $ty_int) -> bool {
let bytes = size_of::<$ty_int>();
let mut buf = [0; 8];
LittleEndian::$write(&mut buf[..bytes], n);
n == LittleEndian::$read(&mut buf[..bytes])
}
qc_sized(prop as fn($ty_int) -> bool, $max - 1);
}
#[test]
fn native_endian() {
fn prop(n: $ty_int) -> bool {
let bytes = size_of::<$ty_int>();
let mut buf = [0; 8];
NativeEndian::$write(&mut buf[..bytes], n);
n == NativeEndian::$read(&mut buf[..bytes])
}
qc_sized(prop as fn($ty_int) -> bool, $max - 1);
}
}
);
}
qc_byte_order!(prop_u16, u16, ::std::u16::MAX as u64, read_u16, write_u16);
qc_byte_order!(prop_i16, i16, ::std::i16::MAX as u64, read_i16, write_i16);
qc_byte_order!(prop_u32, u32, ::std::u32::MAX as u64, read_u32, write_u32);
qc_byte_order!(prop_i32, i32, ::std::i32::MAX as u64, read_i32, write_i32);
qc_byte_order!(prop_u64, u64, ::std::u64::MAX as u64, read_u64, write_u64);
qc_byte_order!(prop_i64, i64, ::std::i64::MAX as u64, read_i64, write_i64);
qc_byte_order!(prop_f32, f32, ::std::u64::MAX as u64, read_f32, write_f32);
qc_byte_order!(prop_f64, f64, ::std::i64::MAX as u64, read_f64, write_f64);
qc_byte_order!(prop_uint_1, u64, super::U64_MAX, 1, read_uint, write_uint);
qc_byte_order!(prop_uint_2, u64, super::U64_MAX, 2, read_uint, write_uint);
qc_byte_order!(prop_uint_3, u64, super::U64_MAX, 3, read_uint, write_uint);
qc_byte_order!(prop_uint_4, u64, super::U64_MAX, 4, read_uint, write_uint);
qc_byte_order!(prop_uint_5, u64, super::U64_MAX, 5, read_uint, write_uint);
qc_byte_order!(prop_uint_6, u64, super::U64_MAX, 6, read_uint, write_uint);
qc_byte_order!(prop_uint_7, u64, super::U64_MAX, 7, read_uint, write_uint);
qc_byte_order!(prop_uint_8, u64, super::U64_MAX, 8, read_uint, write_uint);
qc_byte_order!(prop_int_1, i64, super::I64_MAX, 1, read_int, write_int);
qc_byte_order!(prop_int_2, i64, super::I64_MAX, 2, read_int, write_int);
qc_byte_order!(prop_int_3, i64, super::I64_MAX, 3, read_int, write_int);
qc_byte_order!(prop_int_4, i64, super::I64_MAX, 4, read_int, write_int);
qc_byte_order!(prop_int_5, i64, super::I64_MAX, 5, read_int, write_int);
qc_byte_order!(prop_int_6, i64, super::I64_MAX, 6, read_int, write_int);
qc_byte_order!(prop_int_7, i64, super::I64_MAX, 7, read_int, write_int);
qc_byte_order!(prop_int_8, i64, super::I64_MAX, 8, read_int, write_int);
macro_rules! qc_bytes_ext {
($name:ident, $ty_int:ident, $max:expr,
$bytes:expr, $read:ident, $write:ident) => (
mod $name {
use std::io::Cursor;
use {
ReadBytesExt, WriteBytesExt,
BigEndian, NativeEndian, LittleEndian,
};
use super::qc_sized;
#[test]
fn big_endian() {
let max = ($max - 1) >> (8 * (8 - $bytes));
fn prop(n: $ty_int) -> bool {
let mut wtr = vec![];
wtr.$write::<BigEndian>(n).unwrap();
let mut rdr = Vec::new();
rdr.extend(wtr[8 - $bytes..].iter().map(|&x|x));
let mut rdr = Cursor::new(rdr);
n == rdr.$read::<BigEndian>($bytes).unwrap()
}
qc_sized(prop as fn($ty_int) -> bool, max);
}
#[test]
fn little_endian() {
let max = ($max - 1) >> (8 * (8 - $bytes));
fn prop(n: $ty_int) -> bool {
let mut wtr = vec![];
wtr.$write::<LittleEndian>(n).unwrap();
let mut rdr = Cursor::new(wtr);
n == rdr.$read::<LittleEndian>($bytes).unwrap()
}
qc_sized(prop as fn($ty_int) -> bool, max);
}
#[test]
fn native_endian() {
let max = ($max - 1) >> (8 * (8 - $bytes));
fn prop(n: $ty_int) -> bool {
let mut wtr = vec![];
wtr.$write::<NativeEndian>(n).unwrap();
let mut rdr = Cursor::new(wtr);
n == rdr.$read::<NativeEndian>($bytes).unwrap()
}
qc_sized(prop as fn($ty_int) -> bool, max);
}
}
);
($name:ident, $ty_int:ident, $max:expr, $read:ident, $write:ident) => (
mod $name {
use std::io::Cursor;
use {
ReadBytesExt, WriteBytesExt,
BigEndian, NativeEndian, LittleEndian,
};
use super::qc_sized;
#[test]
fn big_endian() {
fn prop(n: $ty_int) -> bool {
let mut wtr = vec![];
wtr.$write::<BigEndian>(n).unwrap();
let mut rdr = Cursor::new(wtr);
n == rdr.$read::<BigEndian>().unwrap()
}
qc_sized(prop as fn($ty_int) -> bool, $max - 1);
}
#[test]
fn little_endian() {
fn prop(n: $ty_int) -> bool {
let mut wtr = vec![];
wtr.$write::<LittleEndian>(n).unwrap();
let mut rdr = Cursor::new(wtr);
n == rdr.$read::<LittleEndian>().unwrap()
}
qc_sized(prop as fn($ty_int) -> bool, $max - 1);
}
#[test]
fn native_endian() {
fn prop(n: $ty_int) -> bool {
let mut wtr = vec![];
wtr.$write::<NativeEndian>(n).unwrap();
let mut rdr = Cursor::new(wtr);
n == rdr.$read::<NativeEndian>().unwrap()
}
qc_sized(prop as fn($ty_int) -> bool, $max - 1);
}
}
);
}
qc_bytes_ext!(prop_ext_u16, u16, ::std::u16::MAX as u64, read_u16, write_u16);
qc_bytes_ext!(prop_ext_i16, i16, ::std::i16::MAX as u64, read_i16, write_i16);
qc_bytes_ext!(prop_ext_u32, u32, ::std::u32::MAX as u64, read_u32, write_u32);
qc_bytes_ext!(prop_ext_i32, i32, ::std::i32::MAX as u64, read_i32, write_i32);
qc_bytes_ext!(prop_ext_u64, u64, ::std::u64::MAX as u64, read_u64, write_u64);
qc_bytes_ext!(prop_ext_i64, i64, ::std::i64::MAX as u64, read_i64, write_i64);
qc_bytes_ext!(prop_ext_f32, f32, ::std::u64::MAX as u64, read_f32, write_f32);
qc_bytes_ext!(prop_ext_f64, f64, ::std::i64::MAX as u64, read_f64, write_f64);
qc_bytes_ext!(prop_ext_uint_1, u64, super::U64_MAX, 1, read_uint, write_u64);
qc_bytes_ext!(prop_ext_uint_2, u64, super::U64_MAX, 2, read_uint, write_u64);
qc_bytes_ext!(prop_ext_uint_3, u64, super::U64_MAX, 3, read_uint, write_u64);
qc_bytes_ext!(prop_ext_uint_4, u64, super::U64_MAX, 4, read_uint, write_u64);
qc_bytes_ext!(prop_ext_uint_5, u64, super::U64_MAX, 5, read_uint, write_u64);
qc_bytes_ext!(prop_ext_uint_6, u64, super::U64_MAX, 6, read_uint, write_u64);
qc_bytes_ext!(prop_ext_uint_7, u64, super::U64_MAX, 7, read_uint, write_u64);
qc_bytes_ext!(prop_ext_uint_8, u64, super::U64_MAX, 8, read_uint, write_u64);
qc_bytes_ext!(prop_ext_int_1, i64, super::I64_MAX, 1, read_int, write_i64);
qc_bytes_ext!(prop_ext_int_2, i64, super::I64_MAX, 2, read_int, write_i64);
qc_bytes_ext!(prop_ext_int_3, i64, super::I64_MAX, 3, read_int, write_i64);
qc_bytes_ext!(prop_ext_int_4, i64, super::I64_MAX, 4, read_int, write_i64);
qc_bytes_ext!(prop_ext_int_5, i64, super::I64_MAX, 5, read_int, write_i64);
qc_bytes_ext!(prop_ext_int_6, i64, super::I64_MAX, 6, read_int, write_i64);
qc_bytes_ext!(prop_ext_int_7, i64, super::I64_MAX, 7, read_int, write_i64);
qc_bytes_ext!(prop_ext_int_8, i64, super::I64_MAX, 8, read_int, write_i64);
// Test that all of the byte conversion functions panic when given a
// buffer that is too small.
//
// These tests are critical to ensure safety, otherwise we might end up
// with a buffer overflow.
macro_rules! too_small {
($name:ident, $maximally_small:expr, $zero:expr,
$read:ident, $write:ident) => (
mod $name {
use {BigEndian, ByteOrder, NativeEndian, LittleEndian};
#[test]
#[should_panic]
fn read_big_endian() {
let buf = [0; $maximally_small];
BigEndian::$read(&buf);
}
#[test]
#[should_panic]
fn read_little_endian() {
let buf = [0; $maximally_small];
LittleEndian::$read(&buf);
}
#[test]
#[should_panic]
fn read_native_endian() {
let buf = [0; $maximally_small];
NativeEndian::$read(&buf);
}
#[test]
#[should_panic]
fn write_big_endian() {
let mut buf = [0; $maximally_small];
BigEndian::$write(&mut buf, $zero);
}
#[test]
#[should_panic]
fn write_little_endian() {
let mut buf = [0; $maximally_small];
LittleEndian::$write(&mut buf, $zero);
}
#[test]
#[should_panic]
fn write_native_endian() {
let mut buf = [0; $maximally_small];
NativeEndian::$write(&mut buf, $zero);
}
}
);
($name:ident, $maximally_small:expr, $read:ident) => (
mod $name {
use {BigEndian, ByteOrder, NativeEndian, LittleEndian};
#[test]
#[should_panic]
fn read_big_endian() {
let buf = [0; $maximally_small];
BigEndian::$read(&buf, $maximally_small + 1);
}
#[test]
#[should_panic]
fn read_little_endian() {
let buf = [0; $maximally_small];
LittleEndian::$read(&buf, $maximally_small + 1);
}
#[test]
#[should_panic]
fn read_native_endian() {
let buf = [0; $maximally_small];
NativeEndian::$read(&buf, $maximally_small + 1);
}
}
);
}
too_small!(small_u16, 1, 0, read_u16, write_u16);
too_small!(small_i16, 1, 0, read_i16, write_i16);
too_small!(small_u32, 3, 0, read_u32, write_u32);
too_small!(small_i32, 3, 0, read_i32, write_i32);
too_small!(small_u64, 7, 0, read_u64, write_u64);
too_small!(small_i64, 7, 0, read_i64, write_i64);
too_small!(small_f32, 3, 0.0, read_f32, write_f32);
too_small!(small_f64, 7, 0.0, read_f64, write_f64);
too_small!(small_uint_1, 1, read_uint);
too_small!(small_uint_2, 2, read_uint);
too_small!(small_uint_3, 3, read_uint);
too_small!(small_uint_4, 4, read_uint);
too_small!(small_uint_5, 5, read_uint);
too_small!(small_uint_6, 6, read_uint);
too_small!(small_uint_7, 7, read_uint);
too_small!(small_int_1, 1, read_int);
too_small!(small_int_2, 2, read_int);
too_small!(small_int_3, 3, read_int);
too_small!(small_int_4, 4, read_int);
too_small!(small_int_5, 5, read_int);
too_small!(small_int_6, 6, read_int);
too_small!(small_int_7, 7, read_int);
#[test]
fn uint_bigger_buffer() {
use {ByteOrder, LittleEndian};
let n = LittleEndian::read_uint(&[1, 2, 3, 4, 5, 6, 7, 8], 5);
assert_eq!(n, 0x0504030201);
}
}