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// Copyright 2012 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.
/*!
Simple compression
*/
#[allow(missing_doc)];
use std::libc::{c_void, size_t, c_int};
use std::libc;
use std::vec;
pub mod rustrt {
use std::libc::{c_int, c_void, size_t};
#[link_name = "rustrt"]
extern {
pub fn tdefl_compress_mem_to_heap(psrc_buf: *c_void,
src_buf_len: size_t,
pout_len: *mut size_t,
flags: c_int)
-> *c_void;
pub fn tinfl_decompress_mem_to_heap(psrc_buf: *c_void,
src_buf_len: size_t,
pout_len: *mut size_t,
flags: c_int)
-> *c_void;
}
}
static LZ_NONE : c_int = 0x0; // Huffman-coding only.
static LZ_FAST : c_int = 0x1; // LZ with only one probe
static LZ_NORM : c_int = 0x80; // LZ with 128 probes, "normal"
static LZ_BEST : c_int = 0xfff; // LZ with 4095 probes, "best"
static TINFL_FLAG_PARSE_ZLIB_HEADER : c_int = 0x1; // parse zlib header and adler32 checksum
static TDEFL_WRITE_ZLIB_HEADER : c_int = 0x01000; // write zlib header and adler32 checksum
fn deflate_bytes_internal(bytes: &[u8], flags: c_int) -> ~[u8] {
#[fixed_stack_segment]; #[inline(never)];
do bytes.as_imm_buf |b, len| {
unsafe {
let mut outsz : size_t = 0;
let res =
rustrt::tdefl_compress_mem_to_heap(b as *c_void,
len as size_t,
&mut outsz,
flags);
assert!(res as int != 0);
let out = vec::raw::from_buf_raw(res as *u8,
outsz as uint);
libc::free(res);
out
}
}
}
pub fn deflate_bytes(bytes: &[u8]) -> ~[u8] {
deflate_bytes_internal(bytes, LZ_NORM)
}
pub fn deflate_bytes_zlib(bytes: &[u8]) -> ~[u8] {
deflate_bytes_internal(bytes, LZ_NORM | TDEFL_WRITE_ZLIB_HEADER)
}
fn inflate_bytes_internal(bytes: &[u8], flags: c_int) -> ~[u8] {
#[fixed_stack_segment]; #[inline(never)];
do bytes.as_imm_buf |b, len| {
unsafe {
let mut outsz : size_t = 0;
let res =
rustrt::tinfl_decompress_mem_to_heap(b as *c_void,
len as size_t,
&mut outsz,
flags);
assert!(res as int != 0);
let out = vec::raw::from_buf_raw(res as *u8,
outsz as uint);
libc::free(res);
out
}
}
}
pub fn inflate_bytes(bytes: &[u8]) -> ~[u8] {
inflate_bytes_internal(bytes, 0)
}
pub fn inflate_bytes_zlib(bytes: &[u8]) -> ~[u8] {
inflate_bytes_internal(bytes, TINFL_FLAG_PARSE_ZLIB_HEADER)
}
#[cfg(test)]
mod tests {
use super::*;
use std::rand;
use std::rand::Rng;
#[test]
fn test_flate_round_trip() {
let mut r = rand::rng();
let mut words = ~[];
do 20.times {
let range = r.gen_integer_range(1u, 10);
words.push(r.gen_vec::<u8>(range));
}
do 20.times {
let mut input = ~[];
do 2000.times {
input.push_all(r.choose(words));
}
debug!("de/inflate of %u bytes of random word-sequences",
input.len());
let cmp = deflate_bytes(input);
let out = inflate_bytes(cmp);
debug!("%u bytes deflated to %u (%.1f%% size)",
input.len(), cmp.len(),
100.0 * ((cmp.len() as float) / (input.len() as float)));
assert_eq!(input, out);
}
}
#[test]
fn test_zlib_flate() {
let bytes = ~[1, 2, 3, 4, 5];
let deflated = deflate_bytes(bytes);
let inflated = inflate_bytes(deflated);
assert_eq!(inflated, bytes);
}
}
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