1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/js/src/vm/Compression.cpp Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,131 @@
1.4 +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
1.5 + * vim: set ts=8 sts=4 et sw=4 tw=99:
1.6 + * This Source Code Form is subject to the terms of the Mozilla Public
1.7 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.8 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.9 +
1.10 +#include "vm/Compression.h"
1.11 +
1.12 +#include "js/Utility.h"
1.13 +
1.14 +using namespace js;
1.15 +
1.16 +#if USE_ZLIB
1.17 +static void *
1.18 +zlib_alloc(void *cx, uInt items, uInt size)
1.19 +{
1.20 + return js_calloc(items, size);
1.21 +}
1.22 +
1.23 +static void
1.24 +zlib_free(void *cx, void *addr)
1.25 +{
1.26 + js_free(addr);
1.27 +}
1.28 +
1.29 +Compressor::Compressor(const unsigned char *inp, size_t inplen)
1.30 + : inp(inp),
1.31 + inplen(inplen),
1.32 + outbytes(0),
1.33 + initialized(false)
1.34 +{
1.35 + JS_ASSERT(inplen > 0);
1.36 + zs.opaque = nullptr;
1.37 + zs.next_in = (Bytef *)inp;
1.38 + zs.avail_in = 0;
1.39 + zs.next_out = nullptr;
1.40 + zs.avail_out = 0;
1.41 + zs.zalloc = zlib_alloc;
1.42 + zs.zfree = zlib_free;
1.43 +}
1.44 +
1.45 +
1.46 +Compressor::~Compressor()
1.47 +{
1.48 + if (initialized) {
1.49 + int ret = deflateEnd(&zs);
1.50 + if (ret != Z_OK) {
1.51 + // If we finished early, we can get a Z_DATA_ERROR.
1.52 + JS_ASSERT(ret == Z_DATA_ERROR);
1.53 + JS_ASSERT(uInt(zs.next_in - inp) < inplen || !zs.avail_out);
1.54 + }
1.55 + }
1.56 +}
1.57 +
1.58 +bool
1.59 +Compressor::init()
1.60 +{
1.61 + if (inplen >= UINT32_MAX)
1.62 + return false;
1.63 + // zlib is slow and we'd rather be done compression sooner
1.64 + // even if it means decompression is slower which penalizes
1.65 + // Function.toString()
1.66 + int ret = deflateInit(&zs, Z_BEST_SPEED);
1.67 + if (ret != Z_OK) {
1.68 + JS_ASSERT(ret == Z_MEM_ERROR);
1.69 + return false;
1.70 + }
1.71 + initialized = true;
1.72 + return true;
1.73 +}
1.74 +
1.75 +void
1.76 +Compressor::setOutput(unsigned char *out, size_t outlen)
1.77 +{
1.78 + JS_ASSERT(outlen > outbytes);
1.79 + zs.next_out = out + outbytes;
1.80 + zs.avail_out = outlen - outbytes;
1.81 +}
1.82 +
1.83 +Compressor::Status
1.84 +Compressor::compressMore()
1.85 +{
1.86 + JS_ASSERT(zs.next_out);
1.87 + uInt left = inplen - (zs.next_in - inp);
1.88 + bool done = left <= CHUNKSIZE;
1.89 + if (done)
1.90 + zs.avail_in = left;
1.91 + else if (zs.avail_in == 0)
1.92 + zs.avail_in = CHUNKSIZE;
1.93 + Bytef *oldout = zs.next_out;
1.94 + int ret = deflate(&zs, done ? Z_FINISH : Z_NO_FLUSH);
1.95 + outbytes += zs.next_out - oldout;
1.96 + if (ret == Z_MEM_ERROR) {
1.97 + zs.avail_out = 0;
1.98 + return OOM;
1.99 + }
1.100 + if (ret == Z_BUF_ERROR || (done && ret == Z_OK)) {
1.101 + JS_ASSERT(zs.avail_out == 0);
1.102 + return MOREOUTPUT;
1.103 + }
1.104 + JS_ASSERT_IF(!done, ret == Z_OK);
1.105 + JS_ASSERT_IF(done, ret == Z_STREAM_END);
1.106 + return done ? DONE : CONTINUE;
1.107 +}
1.108 +
1.109 +bool
1.110 +js::DecompressString(const unsigned char *inp, size_t inplen, unsigned char *out, size_t outlen)
1.111 +{
1.112 + JS_ASSERT(inplen <= UINT32_MAX);
1.113 + z_stream zs;
1.114 + zs.zalloc = zlib_alloc;
1.115 + zs.zfree = zlib_free;
1.116 + zs.opaque = nullptr;
1.117 + zs.next_in = (Bytef *)inp;
1.118 + zs.avail_in = inplen;
1.119 + zs.next_out = out;
1.120 + JS_ASSERT(outlen);
1.121 + zs.avail_out = outlen;
1.122 + int ret = inflateInit(&zs);
1.123 + if (ret != Z_OK) {
1.124 + JS_ASSERT(ret == Z_MEM_ERROR);
1.125 + return false;
1.126 + }
1.127 + ret = inflate(&zs, Z_FINISH);
1.128 + JS_ASSERT(ret == Z_STREAM_END);
1.129 + ret = inflateEnd(&zs);
1.130 + JS_ASSERT(ret == Z_OK);
1.131 + return true;
1.132 +}
1.133 +#endif /* USE_ZLIB */
1.134 +
