// except according to those terms.
#[inline]
-fn write_to_vec(vec: &mut Vec<u8>, position: usize, byte: u8) {
+pub fn write_to_vec(vec: &mut Vec<u8>, position: usize, byte: u8) {
if position == vec.len() {
vec.push(byte);
} else {
}
}
-#[inline]
-/// encodes an integer using unsigned leb128 encoding and stores
-/// the result using a callback function.
-///
-/// The callback `write` is called once for each position
-/// that is to be written to with the byte to be encoded
-/// at that position.
-pub fn write_unsigned_leb128_to<W>(mut value: u128, mut write: W) -> usize
- where W: FnMut(usize, u8)
-{
- let mut position = 0;
- loop {
- let mut byte = (value & 0x7F) as u8;
- value >>= 7;
- if value != 0 {
- byte |= 0x80;
- }
-
- write(position, byte);
- position += 1;
+#[cfg(target_pointer_width = "32")]
+const USIZE_LEB128_SIZE: usize = 5;
+#[cfg(target_pointer_width = "64")]
+const USIZE_LEB128_SIZE: usize = 10;
+
+macro_rules! leb128_size {
+ (u16) => (3);
+ (u32) => (5);
+ (u64) => (10);
+ (u128) => (19);
+ (usize) => (USIZE_LEB128_SIZE);
+}
- if value == 0 {
- break;
+macro_rules! impl_write_unsigned_leb128 {
+ ($fn_name:ident, $int_ty:ident) => (
+ #[inline]
+ pub fn $fn_name(out: &mut Vec<u8>, start_position: usize, mut value: $int_ty) -> usize {
+ let mut position = start_position;
+ for _ in 0 .. leb128_size!($int_ty) {
+ let mut byte = (value & 0x7F) as u8;
+ value >>= 7;
+ if value != 0 {
+ byte |= 0x80;
+ }
+
+ write_to_vec(out, position, byte);
+ position += 1;
+
+ if value == 0 {
+ break;
+ }
+ }
+
+ position - start_position
}
- }
-
- position
+ )
}
-pub fn write_unsigned_leb128(out: &mut Vec<u8>, start_position: usize, value: u128) -> usize {
- write_unsigned_leb128_to(value, |i, v| write_to_vec(out, start_position+i, v))
+impl_write_unsigned_leb128!(write_u16_leb128, u16);
+impl_write_unsigned_leb128!(write_u32_leb128, u32);
+impl_write_unsigned_leb128!(write_u64_leb128, u64);
+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) => (
+ #[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)
+ };
+ position += 1;
+ result |= ((byte & 0x7F) as $int_ty) << shift;
+ if (byte & 0x80) == 0 {
+ break;
+ }
+ shift += 7;
+ }
+
+ // Do a single bounds check at the end instead of for every byte.
+ assert!(position <= slice.len());
+
+ (result, position)
+ }
+ )
}
-#[inline]
-pub fn read_unsigned_leb128(data: &[u8], start_position: usize) -> (u128, usize) {
- let mut result = 0;
- let mut shift = 0;
- let mut position = start_position;
- loop {
- let byte = data[position];
- position += 1;
- result |= ((byte & 0x7F) as u128) << shift;
- if (byte & 0x80) == 0 {
- break;
- }
- shift += 7;
- }
+impl_read_unsigned_leb128!(read_u16_leb128, u16);
+impl_read_unsigned_leb128!(read_u32_leb128, u32);
+impl_read_unsigned_leb128!(read_u64_leb128, u64);
+impl_read_unsigned_leb128!(read_u128_leb128, u128);
+impl_read_unsigned_leb128!(read_usize_leb128, usize);
+
- (result, position - start_position)
-}
#[inline]
/// encodes an integer using signed leb128 encoding and stores
(result, position - start_position)
}
-#[test]
-fn test_unsigned_leb128() {
- let mut stream = Vec::with_capacity(10000);
-
- for x in 0..62 {
- let pos = stream.len();
- let bytes_written = write_unsigned_leb128(&mut stream, pos, 3 << x);
- assert_eq!(stream.len(), pos + bytes_written);
- }
-
- let mut position = 0;
- for x in 0..62 {
- let expected = 3 << x;
- let (actual, bytes_read) = read_unsigned_leb128(&stream, position);
- assert_eq!(expected, actual);
- position += bytes_read;
- }
- assert_eq!(stream.len(), position);
+macro_rules! impl_test_unsigned_leb128 {
+ ($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 {
+ let pos = stream.len();
+ let bytes_written = $write_fn_name(&mut stream, pos, (3u64 << x) as $int_ty);
+ assert_eq!(stream.len(), pos + bytes_written);
+ }
+
+ let mut position = 0;
+ for x in 0..62 {
+ let expected = (3u64 << x) as $int_ty;
+ let (actual, bytes_read) = $read_fn_name(&stream[position ..]);
+ assert_eq!(expected, actual);
+ position += bytes_read;
+ }
+ assert_eq!(stream.len(), position);
+ }
+ )
}
+impl_test_unsigned_leb128!(test_u16_leb128, write_u16_leb128, read_u16_leb128, u16);
+impl_test_unsigned_leb128!(test_u32_leb128, write_u32_leb128, read_u32_leb128, u32);
+impl_test_unsigned_leb128!(test_u64_leb128, write_u64_leb128, read_u64_leb128, u64);
+impl_test_unsigned_leb128!(test_u128_leb128, write_u128_leb128, read_u128_leb128, u128);
+impl_test_unsigned_leb128!(test_usize_leb128, write_usize_leb128, read_usize_leb128, usize);
+
#[test]
fn test_signed_leb128() {
let values: Vec<_> = (-500..500).map(|i| i * 0x12345789ABCDEF).collect();
// option. This file may not be copied, modified, or distributed
// except according to those terms.
-use leb128::{read_signed_leb128, read_unsigned_leb128, write_signed_leb128, write_unsigned_leb128};
+use leb128::{self, read_signed_leb128, write_signed_leb128};
use std::borrow::Cow;
use std::io::{self, Write};
use serialize;
macro_rules! write_uleb128 {
- ($enc:expr, $value:expr) => {{
+ ($enc:expr, $value:expr, $fun:ident) => {{
let pos = $enc.cursor.position() as usize;
- let bytes_written = write_unsigned_leb128($enc.cursor.get_mut(), pos, $value as u128);
+ let bytes_written = leb128::$fun($enc.cursor.get_mut(), pos, $value);
$enc.cursor.set_position((pos + bytes_written) as u64);
Ok(())
}}
impl<'a> serialize::Encoder for Encoder<'a> {
type Error = io::Error;
+ #[inline]
fn emit_nil(&mut self) -> EncodeResult {
Ok(())
}
+ #[inline]
fn emit_usize(&mut self, v: usize) -> EncodeResult {
- write_uleb128!(self, v)
+ write_uleb128!(self, v, write_usize_leb128)
}
+ #[inline]
fn emit_u128(&mut self, v: u128) -> EncodeResult {
- write_uleb128!(self, v)
+ write_uleb128!(self, v, write_u128_leb128)
}
+ #[inline]
fn emit_u64(&mut self, v: u64) -> EncodeResult {
- write_uleb128!(self, v)
+ write_uleb128!(self, v, write_u64_leb128)
}
+ #[inline]
fn emit_u32(&mut self, v: u32) -> EncodeResult {
- write_uleb128!(self, v)
+ write_uleb128!(self, v, write_u32_leb128)
}
+ #[inline]
fn emit_u16(&mut self, v: u16) -> EncodeResult {
- write_uleb128!(self, v)
+ write_uleb128!(self, v, write_u16_leb128)
}
+ #[inline]
fn emit_u8(&mut self, v: u8) -> EncodeResult {
- let _ = self.cursor.write_all(&[v]);
+ let pos = self.cursor.position() as usize;
+ leb128::write_to_vec(self.cursor.get_mut(), pos, v);
+ self.cursor.set_position((pos + 1) as u64);
Ok(())
}
+ #[inline]
fn emit_isize(&mut self, v: isize) -> EncodeResult {
write_sleb128!(self, v)
}
+ #[inline]
fn emit_i128(&mut self, v: i128) -> EncodeResult {
write_sleb128!(self, v)
}
+ #[inline]
fn emit_i64(&mut self, v: i64) -> EncodeResult {
write_sleb128!(self, v)
}
+ #[inline]
fn emit_i32(&mut self, v: i32) -> EncodeResult {
write_sleb128!(self, v)
}
+ #[inline]
fn emit_i16(&mut self, v: i16) -> EncodeResult {
write_sleb128!(self, v)
}
+ #[inline]
fn emit_i8(&mut self, v: i8) -> EncodeResult {
let as_u8: u8 = unsafe { ::std::mem::transmute(v) };
- let _ = self.cursor.write_all(&[as_u8]);
- Ok(())
+ self.emit_u8(as_u8)
}
+ #[inline]
fn emit_bool(&mut self, v: bool) -> EncodeResult {
self.emit_u8(if v {
1
})
}
+ #[inline]
fn emit_f64(&mut self, v: f64) -> EncodeResult {
let as_u64: u64 = unsafe { ::std::mem::transmute(v) };
self.emit_u64(as_u64)
}
+ #[inline]
fn emit_f32(&mut self, v: f32) -> EncodeResult {
let as_u32: u32 = unsafe { ::std::mem::transmute(v) };
self.emit_u32(as_u32)
}
+ #[inline]
fn emit_char(&mut self, v: char) -> EncodeResult {
self.emit_u32(v as u32)
}
+ #[inline]
fn emit_str(&mut self, v: &str) -> EncodeResult {
self.emit_usize(v.len())?;
let _ = self.cursor.write_all(v.as_bytes());
}
impl<'a> Encoder<'a> {
+ #[inline]
pub fn position(&self) -> usize {
self.cursor.position() as usize
}
}
}
+ #[inline]
pub fn position(&self) -> usize {
self.position
}
+ #[inline]
pub fn set_position(&mut self, pos: usize) {
self.position = pos
}
+ #[inline]
pub fn advance(&mut self, bytes: usize) {
self.position += bytes;
}
}
macro_rules! read_uleb128 {
- ($dec:expr, $t:ty) => ({
- let (value, bytes_read) = read_unsigned_leb128($dec.data, $dec.position);
+ ($dec:expr, $t:ty, $fun:ident) => ({
+ let (value, bytes_read) = leb128::$fun(&$dec.data[$dec.position ..]);
$dec.position += bytes_read;
- Ok(value as $t)
+ Ok(value)
})
}
#[inline]
fn read_u128(&mut self) -> Result<u128, Self::Error> {
- read_uleb128!(self, u128)
+ read_uleb128!(self, u128, read_u128_leb128)
}
#[inline]
fn read_u64(&mut self) -> Result<u64, Self::Error> {
- read_uleb128!(self, u64)
+ read_uleb128!(self, u64, read_u64_leb128)
}
#[inline]
fn read_u32(&mut self) -> Result<u32, Self::Error> {
- read_uleb128!(self, u32)
+ read_uleb128!(self, u32, read_u32_leb128)
}
#[inline]
fn read_u16(&mut self) -> Result<u16, Self::Error> {
- read_uleb128!(self, u16)
+ read_uleb128!(self, u16, read_u16_leb128)
}
#[inline]
#[inline]
fn read_usize(&mut self) -> Result<usize, Self::Error> {
- read_uleb128!(self, usize)
+ read_uleb128!(self, usize, read_usize_leb128)
}
#[inline]
projects / rust.git / commitdiff