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// Copyright 2017 The Chromium OS Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "bsdiff/bz2_compressor.h"
#include <string.h>
#include "bsdiff/logging.h"
namespace {
// The BZ2 compression level used. Smaller compression levels are nowadays
// pointless.
const int kCompressionLevel = 9;
} // namespace
namespace bsdiff {
BZ2Compressor::BZ2Compressor() : comp_buffer_(1024 * 1024) {
memset(&bz_strm_, 0, sizeof(bz_strm_));
int bz_err = BZ2_bzCompressInit(&bz_strm_, kCompressionLevel,
0 /* verbosity */, 0 /* workFactor */);
if (bz_err != BZ_OK) {
LOG(ERROR) << "Initializing bz_strm, bz_error=" << bz_err;
} else {
bz_strm_initialized_ = true;
}
}
BZ2Compressor::~BZ2Compressor() {
if (!bz_strm_initialized_)
return;
int bz_err = BZ2_bzCompressEnd(&bz_strm_);
if (bz_err != BZ_OK) {
LOG(ERROR) << "Deleting the compressor stream, bz_error=" << bz_err;
}
}
bool BZ2Compressor::Write(const uint8_t* buf, size_t size) {
if (!bz_strm_initialized_)
return false;
// The bz_stream struct defines the next_in as a non-const data pointer,
// although the documentation says it won't modify it.
bz_strm_.next_in = reinterpret_cast<char*>(const_cast<uint8_t*>(buf));
bz_strm_.avail_in = size;
while (bz_strm_.avail_in) {
bz_strm_.next_out = reinterpret_cast<char*>(comp_buffer_.buffer_data());
bz_strm_.avail_out = comp_buffer_.buffer_size();
int bz_err = BZ2_bzCompress(&bz_strm_, BZ_RUN);
if (bz_err != BZ_RUN_OK) {
LOG(ERROR) << "Compressing data, bz_error=" << bz_err;
return false;
}
uint64_t output_bytes = comp_buffer_.buffer_size() - bz_strm_.avail_out;
if (output_bytes) {
comp_buffer_.AddDataToChunks(output_bytes);
}
}
return true;
}
bool BZ2Compressor::Finish() {
if (!bz_strm_initialized_)
return false;
bz_strm_.next_in = nullptr;
bz_strm_.avail_in = 0;
int bz_err = BZ_FINISH_OK;
while (bz_err == BZ_FINISH_OK) {
bz_strm_.next_out = reinterpret_cast<char*>(comp_buffer_.buffer_data());
bz_strm_.avail_out = comp_buffer_.buffer_size();
bz_err = BZ2_bzCompress(&bz_strm_, BZ_FINISH);
uint64_t output_bytes = comp_buffer_.buffer_size() - bz_strm_.avail_out;
if (output_bytes) {
comp_buffer_.AddDataToChunks(output_bytes);
}
}
if (bz_err != BZ_STREAM_END) {
LOG(ERROR) << "Finishing compressing data, bz_error=" << bz_err;
return false;
}
bz_err = BZ2_bzCompressEnd(&bz_strm_);
bz_strm_initialized_ = false;
if (bz_err != BZ_OK) {
LOG(ERROR) << "Deleting the compressor stream, bz_error=" << bz_err;
return false;
}
return true;
}
const std::vector<uint8_t>& BZ2Compressor::GetCompressedData() {
return comp_buffer_.GetCompressedData();
}
} // namespace bsdiff
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