-// Copyright 2012-2015 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.
-
#[inline]
pub fn write_to_vec(vec: &mut Vec<u8>, byte: u8) {
vec.push(byte);
const USIZE_LEB128_SIZE: usize = 10;
macro_rules! leb128_size {
- (u16) => (3);
- (u32) => (5);
- (u64) => (10);
- (u128) => (19);
- (usize) => (USIZE_LEB128_SIZE);
+ (u16) => {
+ 3
+ };
+ (u32) => {
+ 5
+ };
+ (u64) => {
+ 10
+ };
+ (u128) => {
+ 19
+ };
+ (usize) => {
+ USIZE_LEB128_SIZE
+ };
}
macro_rules! impl_write_unsigned_leb128 {
- ($fn_name:ident, $int_ty:ident) => (
+ ($fn_name:ident, $int_ty:ident) => {
#[inline]
pub fn $fn_name(out: &mut Vec<u8>, mut value: $int_ty) {
- for _ in 0 .. leb128_size!($int_ty) {
+ for _ in 0..leb128_size!($int_ty) {
let mut byte = (value & 0x7F) as u8;
value >>= 7;
if value != 0 {
}
}
}
- )
+ };
}
impl_write_unsigned_leb128!(write_u16_leb128, u16);
impl_write_unsigned_leb128!(write_u128_leb128, u128);
impl_write_unsigned_leb128!(write_usize_leb128, usize);
-
macro_rules! impl_read_unsigned_leb128 {
- ($fn_name:ident, $int_ty:ident) => (
+ ($fn_name:ident, $int_ty:ident) => {
#[inline]
pub fn $fn_name(slice: &[u8]) -> ($int_ty, usize) {
let mut result: $int_ty = 0;
let mut shift = 0;
let mut position = 0;
- for _ in 0 .. leb128_size!($int_ty) {
- let byte = unsafe {
- *slice.get_unchecked(position)
- };
+ for _ in 0..leb128_size!($int_ty) {
+ let byte = unsafe { *slice.get_unchecked(position) };
position += 1;
result |= ((byte & 0x7F) as $int_ty) << shift;
if (byte & 0x80) == 0 {
(result, position)
}
- )
+ };
}
impl_read_unsigned_leb128!(read_u16_leb128, u16);
impl_read_unsigned_leb128!(read_u128_leb128, u128);
impl_read_unsigned_leb128!(read_usize_leb128, usize);
-
-
#[inline]
/// encodes an integer using signed leb128 encoding and stores
/// the result using a callback function.
/// that is to be written to with the byte to be encoded
/// at that position.
pub fn write_signed_leb128_to<W>(mut value: i128, mut write: W)
- where W: FnMut(u8)
+where
+ W: FnMut(u8),
{
loop {
let mut byte = (value as u8) & 0x7f;
value >>= 7;
- let more = !(((value == 0) && ((byte & 0x40) == 0)) ||
- ((value == -1) && ((byte & 0x40) != 0)));
+ let more =
+ !(((value == 0) && ((byte & 0x40) == 0)) || ((value == -1) && ((byte & 0x40) != 0)));
if more {
byte |= 0x80; // Mark this byte to show that more bytes will follow.
loop {
byte = data[position];
position += 1;
- result |= ((byte & 0x7F) as i128) << shift;
+ result |= i128::from(byte & 0x7F) << shift;
shift += 7;
if (byte & 0x80) == 0 {
(result, position - start_position)
}
-
-macro_rules! impl_test_unsigned_leb128 {
- ($test_name:ident, $write_fn_name:ident, $read_fn_name:ident, $int_ty:ident) => (
- #[test]
- fn $test_name() {
- let mut stream = Vec::new();
-
- for x in 0..62 {
- $write_fn_name(&mut stream, (3u64 << x) as $int_ty);
- }
-
- let mut position = 0;
- for x in 0..62 {
- let expected = (3u64 << x) as $int_ty;
- let (actual, bytes_read) = $read_fn_name(&stream[position ..]);
- assert_eq!(expected, actual);
- position += bytes_read;
- }
- assert_eq!(stream.len(), position);
- }
- )
-}
-
-impl_test_unsigned_leb128!(test_u16_leb128, write_u16_leb128, read_u16_leb128, u16);
-impl_test_unsigned_leb128!(test_u32_leb128, write_u32_leb128, read_u32_leb128, u32);
-impl_test_unsigned_leb128!(test_u64_leb128, write_u64_leb128, read_u64_leb128, u64);
-impl_test_unsigned_leb128!(test_u128_leb128, write_u128_leb128, read_u128_leb128, u128);
-impl_test_unsigned_leb128!(test_usize_leb128, write_usize_leb128, read_usize_leb128, usize);
-
-#[test]
-fn test_signed_leb128() {
- let values: Vec<_> = (-500..500).map(|i| i * 0x12345789ABCDEF).collect();
- let mut stream = Vec::new();
- for &x in &values {
- write_signed_leb128(&mut stream, x);
- }
- let mut pos = 0;
- for &x in &values {
- let (value, bytes_read) = read_signed_leb128(&mut stream, pos);
- pos += bytes_read;
- assert_eq!(x, value);
- }
- assert_eq!(pos, stream.len());
-}