1 // Copyright 2012 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 //! Simple [DEFLATE][def]-based compression. This is a wrapper around the
12 //! [`miniz`][mz] library, which is a one-file pure-C implementation of zlib.
14 //! [def]: https://en.wikipedia.org/wiki/DEFLATE
15 //! [mz]: https://code.google.com/p/miniz/
17 #![crate_name = "flate"]
19 #![crate_type = "rlib"]
20 #![crate_type = "dylib"]
21 #![doc(html_logo_url = "http://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
22 html_favicon_url = "http://www.rust-lang.org/favicon.ico",
23 html_root_url = "http://doc.rust-lang.org/nightly/")]
24 #![feature(phase, unboxed_closures, associated_types)]
26 #[cfg(test)] #[phase(plugin, link)] extern crate log;
30 use libc::{c_void, size_t, c_int};
40 impl Deref for Bytes {
42 fn deref(&self) -> &[u8] {
43 unsafe { slice::from_raw_mut_buf(&self.ptr.0, self.len) }
49 unsafe { libc::free(self.ptr.0 as *mut _); }
53 #[link(name = "miniz", kind = "static")]
55 /// Raw miniz compression function.
56 fn tdefl_compress_mem_to_heap(psrc_buf: *const c_void,
58 pout_len: *mut size_t,
62 /// Raw miniz decompression function.
63 fn tinfl_decompress_mem_to_heap(psrc_buf: *const c_void,
65 pout_len: *mut size_t,
70 static LZ_NORM : c_int = 0x80; // LZ with 128 probes, "normal"
71 static TINFL_FLAG_PARSE_ZLIB_HEADER : c_int = 0x1; // parse zlib header and adler32 checksum
72 static TDEFL_WRITE_ZLIB_HEADER : c_int = 0x01000; // write zlib header and adler32 checksum
74 fn deflate_bytes_internal(bytes: &[u8], flags: c_int) -> Option<Bytes> {
76 let mut outsz : size_t = 0;
77 let res = tdefl_compress_mem_to_heap(bytes.as_ptr() as *const _,
78 bytes.len() as size_t,
82 let res = Unique(res as *mut u8);
83 Some(Bytes { ptr: res, len: outsz as uint })
90 /// Compress a buffer, without writing any sort of header on the output.
91 pub fn deflate_bytes(bytes: &[u8]) -> Option<Bytes> {
92 deflate_bytes_internal(bytes, LZ_NORM)
95 /// Compress a buffer, using a header that zlib can understand.
96 pub fn deflate_bytes_zlib(bytes: &[u8]) -> Option<Bytes> {
97 deflate_bytes_internal(bytes, LZ_NORM | TDEFL_WRITE_ZLIB_HEADER)
100 fn inflate_bytes_internal(bytes: &[u8], flags: c_int) -> Option<Bytes> {
102 let mut outsz : size_t = 0;
103 let res = tinfl_decompress_mem_to_heap(bytes.as_ptr() as *const _,
104 bytes.len() as size_t,
108 let res = Unique(res as *mut u8);
109 Some(Bytes { ptr: res, len: outsz as uint })
116 /// Decompress a buffer, without parsing any sort of header on the input.
117 pub fn inflate_bytes(bytes: &[u8]) -> Option<Bytes> {
118 inflate_bytes_internal(bytes, 0)
121 /// Decompress a buffer that starts with a zlib header.
122 pub fn inflate_bytes_zlib(bytes: &[u8]) -> Option<Bytes> {
123 inflate_bytes_internal(bytes, TINFL_FLAG_PARSE_ZLIB_HEADER)
128 use super::{inflate_bytes, deflate_bytes};
133 fn test_flate_round_trip() {
134 let mut r = rand::thread_rng();
135 let mut words = vec!();
136 for _ in range(0u, 20) {
137 let range = r.gen_range(1u, 10);
138 let v = r.gen_iter::<u8>().take(range).collect::<Vec<u8>>();
141 for _ in range(0u, 20) {
142 let mut input = vec![];
143 for _ in range(0u, 2000) {
144 input.push_all(r.choose(words.as_slice()).unwrap().as_slice());
146 debug!("de/inflate of {} bytes of random word-sequences",
148 let cmp = deflate_bytes(input.as_slice()).expect("deflation failed");
149 let out = inflate_bytes(cmp.as_slice()).expect("inflation failed");
150 debug!("{} bytes deflated to {} ({:.1}% size)",
151 input.len(), cmp.len(),
152 100.0 * ((cmp.len() as f64) / (input.len() as f64)));
153 assert_eq!(input, out.as_slice());
158 fn test_zlib_flate() {
159 let bytes = vec!(1, 2, 3, 4, 5);
160 let deflated = deflate_bytes(bytes.as_slice()).expect("deflation failed");
161 let inflated = inflate_bytes(deflated.as_slice()).expect("inflation failed");
162 assert_eq!(inflated.as_slice(), bytes);