The Tor Browser: js/src/vm/Compression.cpp@6474c204b198

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

     1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-

     2  * vim: set ts=8 sts=4 et sw=4 tw=99:

     3  * This Source Code Form is subject to the terms of the Mozilla Public

     4  * License, v. 2.0. If a copy of the MPL was not distributed with this

     5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

     7 #include "vm/Compression.h"

     9 #include "js/Utility.h"

    11 using namespace js;

    13 #if USE_ZLIB

    14 static void *

    15 zlib_alloc(void *cx, uInt items, uInt size)

    16 {

    17     return js_calloc(items, size);

    18 }

    20 static void

    21 zlib_free(void *cx, void *addr)

    22 {

    23     js_free(addr);

    24 }

    26 Compressor::Compressor(const unsigned char *inp, size_t inplen)

    27     : inp(inp),

    28       inplen(inplen),

    29       outbytes(0),

    30       initialized(false)

    31 {

    32     JS_ASSERT(inplen > 0);

    33     zs.opaque = nullptr;

    34     zs.next_in = (Bytef *)inp;

    35     zs.avail_in = 0;

    36     zs.next_out = nullptr;

    37     zs.avail_out = 0;

    38     zs.zalloc = zlib_alloc;

    39     zs.zfree = zlib_free;

    40 }

    43 Compressor::~Compressor()

    44 {

    45     if (initialized) {

    46         int ret = deflateEnd(&zs);

    47         if (ret != Z_OK) {

    48             // If we finished early, we can get a Z_DATA_ERROR.

    49             JS_ASSERT(ret == Z_DATA_ERROR);

    50             JS_ASSERT(uInt(zs.next_in - inp) < inplen || !zs.avail_out);

    51         }

    52     }

    53 }

    55 bool

    56 Compressor::init()

    57 {

    58     if (inplen >= UINT32_MAX)

    59         return false;

    60     // zlib is slow and we'd rather be done compression sooner

    61     // even if it means decompression is slower which penalizes

    62     // Function.toString()

    63     int ret = deflateInit(&zs, Z_BEST_SPEED);

    64     if (ret != Z_OK) {

    65         JS_ASSERT(ret == Z_MEM_ERROR);

    66         return false;

    67     }

    68     initialized = true;

    69     return true;

    70 }

    72 void

    73 Compressor::setOutput(unsigned char *out, size_t outlen)

    74 {

    75     JS_ASSERT(outlen > outbytes);

    76     zs.next_out = out + outbytes;

    77     zs.avail_out = outlen - outbytes;

    78 }

    80 Compressor::Status

    81 Compressor::compressMore()

    82 {

    83     JS_ASSERT(zs.next_out);

    84     uInt left = inplen - (zs.next_in - inp);

    85     bool done = left <= CHUNKSIZE;

    86     if (done)

    87         zs.avail_in = left;

    88     else if (zs.avail_in == 0)

    89         zs.avail_in = CHUNKSIZE;

    90     Bytef *oldout = zs.next_out;

    91     int ret = deflate(&zs, done ? Z_FINISH : Z_NO_FLUSH);

    92     outbytes += zs.next_out - oldout;

    93     if (ret == Z_MEM_ERROR) {

    94         zs.avail_out = 0;

    95         return OOM;

    96     }

    97     if (ret == Z_BUF_ERROR || (done && ret == Z_OK)) {

    98         JS_ASSERT(zs.avail_out == 0);

    99         return MOREOUTPUT;

   100     }

   101     JS_ASSERT_IF(!done, ret == Z_OK);

   102     JS_ASSERT_IF(done, ret == Z_STREAM_END);

   103     return done ? DONE : CONTINUE;

   104 }

   106 bool

   107 js::DecompressString(const unsigned char *inp, size_t inplen, unsigned char *out, size_t outlen)

   108 {

   109     JS_ASSERT(inplen <= UINT32_MAX);

   110     z_stream zs;

   111     zs.zalloc = zlib_alloc;

   112     zs.zfree = zlib_free;

   113     zs.opaque = nullptr;

   114     zs.next_in = (Bytef *)inp;

   115     zs.avail_in = inplen;

   116     zs.next_out = out;

   117     JS_ASSERT(outlen);

   118     zs.avail_out = outlen;

   119     int ret = inflateInit(&zs);

   120     if (ret != Z_OK) {

   121         JS_ASSERT(ret == Z_MEM_ERROR);

   122         return false;

   123     }

   124     ret = inflate(&zs, Z_FINISH);

   125     JS_ASSERT(ret == Z_STREAM_END);

   126     ret = inflateEnd(&zs);

   127     JS_ASSERT(ret == Z_OK);

   128     return true;

   129 }

   130 #endif /* USE_ZLIB */

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