mfbt/Compression.cpp

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   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/. */
   6
   7 #include "mozilla/Compression.h"
   8 #include "mozilla/CheckedInt.h"
   9
  10 // Without including <string>, MSVC 2015 complains about e.g. the impossibility
  11 // to convert `const void* const` to `void*` when calling memchr from
  12 // corecrt_memory.h.
  13 #include <string>
  14
  15 // Because we wrap lz4.c in an anonymous namespace, all of its #includes
  16 // go in the anonymous namespace too. This would create conflicting
  17 // declarations for intrinsic functions that are internally defined
  18 // at top-level. Including intrin.h here prevents it from being included
  19 // later within the anonymous namespace.
  20 #ifdef _MSC_VER
  21 #include <intrin.h>
  22 #endif
  23
  24 using namespace mozilla::Compression;
  25
  26 namespace {
  27
  28 #include "lz4.c"
  29
  30 }/* anonymous namespace */
  31
  32 /* Our wrappers */
  33
  34 size_t
  35 LZ4::compress(const char* aSource, size_t aInputSize, char* aDest)
  36 {
  37   CheckedInt<int> inputSizeChecked = aInputSize;
  38   MOZ_ASSERT(inputSizeChecked.isValid());
  39   return LZ4_compress(aSource, aDest, inputSizeChecked.value());
  40 }
  41
  42 size_t
  43 LZ4::compressLimitedOutput(const char* aSource, size_t aInputSize, char* aDest,
  44                            size_t aMaxOutputSize)
  45 {
  46   CheckedInt<int> inputSizeChecked = aInputSize;
  47   MOZ_ASSERT(inputSizeChecked.isValid());
  48   CheckedInt<int> maxOutputSizeChecked = aMaxOutputSize;
  49   MOZ_ASSERT(maxOutputSizeChecked.isValid());
  50   return LZ4_compress_limitedOutput(aSource, aDest, inputSizeChecked.value(),
  51                                     maxOutputSizeChecked.value());
  52 }
  53
  54 bool
  55 LZ4::decompress(const char* aSource, char* aDest, size_t aOutputSize)
  56 {
  57   CheckedInt<int> outputSizeChecked = aOutputSize;
  58   MOZ_ASSERT(outputSizeChecked.isValid());
  59   int ret = LZ4_decompress_fast(aSource, aDest, outputSizeChecked.value());
  60   return ret >= 0;
  61 }
  62
  63 bool
  64 LZ4::decompress(const char* aSource, size_t aInputSize, char* aDest,
  65                 size_t aMaxOutputSize, size_t* aOutputSize)
  66 {
  67   CheckedInt<int> maxOutputSizeChecked = aMaxOutputSize;
  68   MOZ_ASSERT(maxOutputSizeChecked.isValid());
  69   CheckedInt<int> inputSizeChecked = aInputSize;
  70   MOZ_ASSERT(inputSizeChecked.isValid());
  71
  72   int ret = LZ4_decompress_safe(aSource, aDest, inputSizeChecked.value(),
  73                                 maxOutputSizeChecked.value());
  74   if (ret >= 0) {
  75     *aOutputSize = ret;
  76     return true;
  77   }
  78
  79   *aOutputSize = 0;
  80   return false;
  81 }
  82