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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 [DEFLATE][def]-based compression. This is a wrapper around the
//! [`miniz`][mz] library, which is a one-file pure-C implementation of zlib.
//!
//! [def]: https://en.wikipedia.org/wiki/DEFLATE
//! [mz]: https://code.google.com/p/miniz/
#![crate_name = "flate"]
#![unstable(feature = "rustc_private")]
#![staged_api]
#![crate_type = "rlib"]
#![crate_type = "dylib"]
#![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://doc.rust-lang.org/nightly/")]
#![feature(core)]
#![feature(int_uint)]
#![feature(libc)]
#![feature(staged_api)]
#[cfg(test)] #[macro_use] extern crate log;
extern crate libc;
use libc::{c_void, size_t, c_int};
use std::ops::Deref;
use std::ptr::Unique;
use std::slice;
pub struct Bytes {
ptr: Unique<u8>,
len: uint,
}
impl Deref for Bytes {
type Target = [u8];
fn deref(&self) -> &[u8] {
unsafe { slice::from_raw_parts(*self.ptr, self.len) }
}
}
impl Drop for Bytes {
fn drop(&mut self) {
unsafe { libc::free(*self.ptr as *mut _); }
}
}
#[link(name = "miniz", kind = "static")]
extern {
/// Raw miniz compression function.
fn tdefl_compress_mem_to_heap(psrc_buf: *const c_void,
src_buf_len: size_t,
pout_len: *mut size_t,
flags: c_int)
-> *mut c_void;
/// Raw miniz decompression function.
fn tinfl_decompress_mem_to_heap(psrc_buf: *const 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) -> Option<Bytes> {
unsafe {
let mut outsz : size_t = 0;
let res = tdefl_compress_mem_to_heap(bytes.as_ptr() as *const _,
bytes.len() as size_t,
&mut outsz,
flags);
if !res.is_null() {
let res = Unique::new(res as *mut u8);
Some(Bytes { ptr: res, len: outsz as uint })
} else {
None
}
}
}
/// Compress a buffer, without writing any sort of header on the output.
pub fn deflate_bytes(bytes: &[u8]) -> Option<Bytes> {
deflate_bytes_internal(bytes, LZ_NORM)
}
/// Compress a buffer, using a header that zlib can understand.
pub fn deflate_bytes_zlib(bytes: &[u8]) -> Option<Bytes> {
deflate_bytes_internal(bytes, LZ_NORM | TDEFL_WRITE_ZLIB_HEADER)
}
fn inflate_bytes_internal(bytes: &[u8], flags: c_int) -> Option<Bytes> {
unsafe {
let mut outsz : size_t = 0;
let res = tinfl_decompress_mem_to_heap(bytes.as_ptr() as *const _,
bytes.len() as size_t,
&mut outsz,
flags);
if !res.is_null() {
let res = Unique::new(res as *mut u8);
Some(Bytes { ptr: res, len: outsz as uint })
} else {
None
}
}
}
/// Decompress a buffer, without parsing any sort of header on the input.
pub fn inflate_bytes(bytes: &[u8]) -> Option<Bytes> {
inflate_bytes_internal(bytes, 0)
}
/// Decompress a buffer that starts with a zlib header.
pub fn inflate_bytes_zlib(bytes: &[u8]) -> Option<Bytes> {
inflate_bytes_internal(bytes, TINFL_FLAG_PARSE_ZLIB_HEADER)
}
#[cfg(test)]
mod tests {
#![allow(deprecated)]
use super::{inflate_bytes, deflate_bytes};
use std::rand;
use std::rand::Rng;
#[test]
fn test_flate_round_trip() {
let mut r = rand::thread_rng();
let mut words = vec!();
for _ in 0..20 {
let range = r.gen_range(1, 10);
let v = r.gen_iter::<u8>().take(range).collect::<Vec<u8>>();
words.push(v);
}
for _ in 0..20 {
let mut input = vec![];
for _ in 0..2000 {
input.push_all(r.choose(&words).unwrap());
}
debug!("de/inflate of {} bytes of random word-sequences",
input.len());
let cmp = deflate_bytes(&input).expect("deflation failed");
let out = inflate_bytes(&cmp).expect("inflation failed");
debug!("{} bytes deflated to {} ({:.1}% size)",
input.len(), cmp.len(),
100.0 * ((cmp.len() as f64) / (input.len() as f64)));
assert_eq!(&*input, &*out);
}
}
#[test]
fn test_zlib_flate() {
let bytes = vec!(1, 2, 3, 4, 5);
let deflated = deflate_bytes(&bytes).expect("deflation failed");
let inflated = inflate_bytes(&deflated).expect("inflation failed");
assert_eq!(&*inflated, &*bytes);
}
}
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