1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135

// 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

*/

#![crate_id = "flate#0.10"]
#![crate_type = "rlib"]
#![crate_type = "dylib"]
#![license = "MIT/ASL2"]
#![doc(html_logo_url = "http://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
       html_favicon_url = "http://www.rust-lang.org/favicon.ico",
       html_root_url = "http://static.rust-lang.org/doc/master")]
#![feature(phase)]
#![deny(deprecated_owned_vector)]

#[cfg(test)] #[phase(syntax, link)] extern crate log;

use std::libc::{c_void, size_t, c_int};
use std::libc;
use std::c_vec::CVec;

pub mod rustrt {
    use std::libc::{c_int, c_void, size_t};

    #[link(name = "miniz", kind = "static")]
    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)
                                          -> *mut 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)
                                            -> *mut c_void;
    }
}

static LZ_NORM : c_int = 0x80;  // LZ with 128 probes, "normal"
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) -> CVec<u8> {
    unsafe {
        let mut outsz : size_t = 0;
        let res = rustrt::tdefl_compress_mem_to_heap(bytes.as_ptr() as *c_void,
                                                     bytes.len() as size_t,
                                                     &mut outsz,
                                                     flags);
        assert!(!res.is_null());
        CVec::new_with_dtor(res as *mut u8, outsz as uint, proc() libc::free(res))
    }
}

pub fn deflate_bytes(bytes: &[u8]) -> CVec<u8> {
    deflate_bytes_internal(bytes, LZ_NORM)
}

pub fn deflate_bytes_zlib(bytes: &[u8]) -> CVec<u8> {
    deflate_bytes_internal(bytes, LZ_NORM | TDEFL_WRITE_ZLIB_HEADER)
}

fn inflate_bytes_internal(bytes: &[u8], flags: c_int) -> CVec<u8> {
    unsafe {
        let mut outsz : size_t = 0;
        let res = rustrt::tinfl_decompress_mem_to_heap(bytes.as_ptr() as *c_void,
                                                       bytes.len() as size_t,
                                                       &mut outsz,
                                                       flags);
        assert!(!res.is_null());
        CVec::new_with_dtor(res as *mut u8, outsz as uint, proc() libc::free(res))
    }
}

pub fn inflate_bytes(bytes: &[u8]) -> CVec<u8> {
    inflate_bytes_internal(bytes, 0)
}

pub fn inflate_bytes_zlib(bytes: &[u8]) -> CVec<u8> {
    inflate_bytes_internal(bytes, TINFL_FLAG_PARSE_ZLIB_HEADER)
}

#[cfg(test)]
mod tests {
    extern crate rand;

    use super::{inflate_bytes, deflate_bytes};
    use self::rand::Rng;

    #[test]
    #[allow(deprecated_owned_vector)]
    fn test_flate_round_trip() {
        let mut r = rand::task_rng();
        let mut words = vec!();
        for _ in range(0, 20) {
            let range = r.gen_range(1u, 10);
            words.push(r.gen_vec::<u8>(range));
        }
        for _ in range(0, 20) {
            let mut input = ~[];
            for _ in range(0, 2000) {
                input.push_all(r.choose(words.as_slice()));
            }
            debug!("de/inflate of {} bytes of random word-sequences",
                   input.len());
            let cmp = deflate_bytes(input);
            let out = inflate_bytes(cmp.as_slice());
            debug!("{} bytes deflated to {} ({:.1f}% size)",
                   input.len(), cmp.len(),
                   100.0 * ((cmp.len() as f64) / (input.len() as f64)));
            assert_eq!(input.as_slice(), out.as_slice());
        }
    }

    #[test]
    fn test_zlib_flate() {
        let bytes = vec!(1, 2, 3, 4, 5);
        let deflated = deflate_bytes(bytes.as_slice());
        let inflated = inflate_bytes(deflated.as_slice());
        assert_eq!(inflated.as_slice(), bytes.as_slice());
    }
}