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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "mozilla/Compression.h"
#include "mozilla/CheckedInt.h"
// Without including <string>, MSVC 2015 complains about e.g. the impossibility
// to convert `const void* const` to `void*` when calling memchr from
// corecrt_memory.h.
#include <string>
#include "lz4/lz4.h"
#include "lz4/lz4frame.h"
using namespace mozilla;
using namespace mozilla::Compression;
/* Our wrappers */
size_t LZ4::compress(const char* aSource, size_t aInputSize, char* aDest) {
CheckedInt<int> inputSizeChecked = aInputSize;
MOZ_ASSERT(inputSizeChecked.isValid());
return LZ4_compress_default(aSource, aDest, inputSizeChecked.value(),
LZ4_compressBound(inputSizeChecked.value()));
}
size_t LZ4::compressLimitedOutput(const char* aSource, size_t aInputSize,
char* aDest, size_t aMaxOutputSize) {
CheckedInt<int> inputSizeChecked = aInputSize;
MOZ_ASSERT(inputSizeChecked.isValid());
CheckedInt<int> maxOutputSizeChecked = aMaxOutputSize;
MOZ_ASSERT(maxOutputSizeChecked.isValid());
return LZ4_compress_default(aSource, aDest, inputSizeChecked.value(),
maxOutputSizeChecked.value());
}
bool LZ4::decompress(const char* aSource, size_t aInputSize, char* aDest,
size_t aMaxOutputSize, size_t* aOutputSize) {
CheckedInt<int> maxOutputSizeChecked = aMaxOutputSize;
MOZ_ASSERT(maxOutputSizeChecked.isValid());
CheckedInt<int> inputSizeChecked = aInputSize;
MOZ_ASSERT(inputSizeChecked.isValid());
int ret = LZ4_decompress_safe(aSource, aDest, inputSizeChecked.value(),
maxOutputSizeChecked.value());
if (ret >= 0) {
*aOutputSize = ret;
return true;
}
*aOutputSize = 0;
return false;
}
bool LZ4::decompressPartial(const char* aSource, size_t aInputSize, char* aDest,
size_t aMaxOutputSize, size_t* aOutputSize) {
CheckedInt<int> maxOutputSizeChecked = aMaxOutputSize;
MOZ_ASSERT(maxOutputSizeChecked.isValid());
CheckedInt<int> inputSizeChecked = aInputSize;
MOZ_ASSERT(inputSizeChecked.isValid());
int ret = LZ4_decompress_safe_partial(
aSource, aDest, inputSizeChecked.value(), maxOutputSizeChecked.value(),
maxOutputSizeChecked.value());
if (ret >= 0) {
*aOutputSize = ret;
return true;
}
*aOutputSize = 0;
return false;
}
LZ4FrameCompressionContext::LZ4FrameCompressionContext(int aCompressionLevel,
size_t aMaxSrcSize,
bool aChecksum,
bool aStableSrc)
: mContext(nullptr),
mCompressionLevel(aCompressionLevel),
mGenerateChecksum(aChecksum),
mStableSrc(aStableSrc),
mMaxSrcSize(aMaxSrcSize),
mWriteBufLen(0) {
LZ4F_contentChecksum_t checksum =
mGenerateChecksum ? LZ4F_contentChecksumEnabled : LZ4F_noContentChecksum;
LZ4F_preferences_t prefs = {
{
LZ4F_max256KB,
LZ4F_blockLinked,
checksum,
},
mCompressionLevel,
};
mWriteBufLen = LZ4F_compressBound(mMaxSrcSize, &prefs);
LZ4F_errorCode_t err = LZ4F_createCompressionContext(&mContext, LZ4F_VERSION);
MOZ_RELEASE_ASSERT(!LZ4F_isError(err));
}
LZ4FrameCompressionContext::~LZ4FrameCompressionContext() {
LZ4F_freeCompressionContext(mContext);
}
Result<Span<const char>, size_t> LZ4FrameCompressionContext::BeginCompressing(
Span<char> aWriteBuffer) {
mWriteBuffer = aWriteBuffer;
LZ4F_contentChecksum_t checksum =
mGenerateChecksum ? LZ4F_contentChecksumEnabled : LZ4F_noContentChecksum;
LZ4F_preferences_t prefs = {
{
LZ4F_max256KB,
LZ4F_blockLinked,
checksum,
},
mCompressionLevel,
};
size_t headerSize = LZ4F_compressBegin(mContext, mWriteBuffer.Elements(),
mWriteBufLen, &prefs);
if (LZ4F_isError(headerSize)) {
return Err(headerSize);
}
return Span{static_cast<const char*>(mWriteBuffer.Elements()), headerSize};
}
Result<Span<const char>, size_t>
LZ4FrameCompressionContext::ContinueCompressing(Span<const char> aInput) {
LZ4F_compressOptions_t opts = {};
opts.stableSrc = (uint32_t)mStableSrc;
size_t outputSize =
LZ4F_compressUpdate(mContext, mWriteBuffer.Elements(), mWriteBufLen,
aInput.Elements(), aInput.Length(), &opts);
if (LZ4F_isError(outputSize)) {
return Err(outputSize);
}
return Span{static_cast<const char*>(mWriteBuffer.Elements()), outputSize};
}
Result<Span<const char>, size_t> LZ4FrameCompressionContext::EndCompressing() {
size_t outputSize =
LZ4F_compressEnd(mContext, mWriteBuffer.Elements(), mWriteBufLen,
/* options */ nullptr);
if (LZ4F_isError(outputSize)) {
return Err(outputSize);
}
return Span{static_cast<const char*>(mWriteBuffer.Elements()), outputSize};
}
LZ4FrameDecompressionContext::LZ4FrameDecompressionContext(bool aStableDest)
: mContext(nullptr), mStableDest(aStableDest) {
LZ4F_errorCode_t err =
LZ4F_createDecompressionContext(&mContext, LZ4F_VERSION);
MOZ_RELEASE_ASSERT(!LZ4F_isError(err));
}
LZ4FrameDecompressionContext::~LZ4FrameDecompressionContext() {
LZ4F_freeDecompressionContext(mContext);
}
Result<LZ4FrameDecompressionResult, size_t>
LZ4FrameDecompressionContext::Decompress(Span<char> aOutput,
Span<const char> aInput) {
LZ4F_decompressOptions_t opts = {};
opts.stableDst = (uint32_t)mStableDest;
size_t outBytes = aOutput.Length();
size_t inBytes = aInput.Length();
size_t result = LZ4F_decompress(mContext, aOutput.Elements(), &outBytes,
aInput.Elements(), &inBytes, &opts);
if (LZ4F_isError(result)) {
return Err(result);
}
LZ4FrameDecompressionResult decompressionResult = {};
decompressionResult.mFinished = !result;
decompressionResult.mSizeRead = inBytes;
decompressionResult.mSizeWritten = outBytes;
return decompressionResult;
}
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