107 lines
3.5 KiB
Rust
107 lines
3.5 KiB
Rust
// Copyright 2012 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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/*!
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Simple compression
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*/
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use libc;
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use libc::{c_void, size_t, c_int};
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use vec;
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#[cfg(test)] use rand;
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#[cfg(test)] use rand::RngUtil;
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pub mod rustrt {
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use libc::{c_int, c_void, size_t};
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#[link_name = "rustrt"]
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pub extern {
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unsafe fn tdefl_compress_mem_to_heap(psrc_buf: *const c_void,
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src_buf_len: size_t,
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pout_len: *mut size_t,
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flags: c_int)
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-> *c_void;
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unsafe fn tinfl_decompress_mem_to_heap(psrc_buf: *const c_void,
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src_buf_len: size_t,
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pout_len: *mut size_t,
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flags: c_int)
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-> *c_void;
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}
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}
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static lz_none : c_int = 0x0; // Huffman-coding only.
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static lz_fast : c_int = 0x1; // LZ with only one probe
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static lz_norm : c_int = 0x80; // LZ with 128 probes, "normal"
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static lz_best : c_int = 0xfff; // LZ with 4095 probes, "best"
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pub fn deflate_bytes(bytes: &const [u8]) -> ~[u8] {
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do vec::as_const_buf(bytes) |b, len| {
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unsafe {
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let mut outsz : size_t = 0;
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let res =
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rustrt::tdefl_compress_mem_to_heap(b as *c_void,
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len as size_t,
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&mut outsz,
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lz_norm);
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assert!(res as int != 0);
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let out = vec::raw::from_buf_raw(res as *u8,
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outsz as uint);
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libc::free(res);
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out
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}
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}
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}
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pub fn inflate_bytes(bytes: &const [u8]) -> ~[u8] {
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do vec::as_const_buf(bytes) |b, len| {
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unsafe {
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let mut outsz : size_t = 0;
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let res =
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rustrt::tinfl_decompress_mem_to_heap(b as *c_void,
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len as size_t,
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&mut outsz,
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0);
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assert!(res as int != 0);
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let out = vec::raw::from_buf_raw(res as *u8,
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outsz as uint);
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libc::free(res);
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out
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}
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}
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}
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#[test]
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#[allow(non_implicitly_copyable_typarams)]
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fn test_flate_round_trip() {
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let r = rand::rng();
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let mut words = ~[];
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for 20.times {
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words.push(r.gen_bytes(r.gen_uint_range(1, 10)));
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}
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for 20.times {
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let mut in = ~[];
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for 2000.times {
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in.push_all(r.choose(words));
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}
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debug!("de/inflate of %u bytes of random word-sequences",
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in.len());
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let cmp = deflate_bytes(in);
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let out = inflate_bytes(cmp);
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debug!("%u bytes deflated to %u (%.1f%% size)",
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in.len(), cmp.len(),
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100.0 * ((cmp.len() as float) / (in.len() as float)));
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assert!((in == out));
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}
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}
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