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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
*/
use libc;
use libc::{c_void, size_t, c_int};
use ptr;
use rand::RngUtil;
use vec;
#[cfg(test)] use rand;
pub mod rustrt {
use libc::{c_int, c_void, size_t};
#[link_name = "rustrt"]
pub extern {
unsafe fn tdefl_compress_mem_to_heap(psrc_buf: *const c_void,
src_buf_len: size_t,
pout_len: *size_t,
flags: c_int)
-> *c_void;
unsafe fn tinfl_decompress_mem_to_heap(psrc_buf: *const c_void,
src_buf_len: size_t,
pout_len: *size_t,
flags: c_int)
-> *c_void;
}
}
const lz_none : c_int = 0x0; // Huffman-coding only.
const lz_fast : c_int = 0x1; // LZ with only one probe
const lz_norm : c_int = 0x80; // LZ with 128 probes, "normal"
const lz_best : c_int = 0xfff; // LZ with 4095 probes, "best"
pub fn deflate_bytes(bytes: &[const u8]) -> ~[u8] {
do vec::as_const_buf(bytes) |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,
ptr::addr_of(&outsz),
lz_norm);
fail_unless!(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: &[const u8]) -> ~[u8] {
do vec::as_const_buf(bytes) |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,
ptr::addr_of(&outsz),
0);
fail_unless!(res as int != 0);
let out = vec::raw::from_buf_raw(res as *u8,
outsz as uint);
libc::free(res);
out
}
}
}
#[test]
#[allow(non_implicitly_copyable_typarams)]
fn test_flate_round_trip() {
let r = rand::Rng();
let mut words = ~[];
for 20.times {
words.push(r.gen_bytes(r.gen_uint_range(1, 10)));
}
for 20.times {
let mut in = ~[];
for 2000.times {
in.push_all(r.choose(words));
}
debug!("de/inflate of %u bytes of random word-sequences",
in.len());
let cmp = deflate_bytes(in);
let out = inflate_bytes(cmp);
debug!("%u bytes deflated to %u (%.1f%% size)",
in.len(), cmp.len(),
100.0 * ((cmp.len() as float) / (in.len() as float)));
fail_unless!((in == out));
}
}
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