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/**
* Copyright (C) 2015 MongoDB Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License, version 3,
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* As a special exception, the copyright holders give permission to link the
* code of portions of this program with the OpenSSL library under certain
* conditions as described in each individual source file and distribute
* linked combinations including the program with the OpenSSL library. You
* must comply with the GNU Affero General Public License in all respects
* for all of the code used other than as permitted herein. If you modify
* file(s) with this exception, you may extend this exception to your
* version of the file(s), but you are not obligated to do so. If you do not
* wish to do so, delete this exception statement from your version. If you
* delete this exception statement from all source files in the program,
* then also delete it in the license file.
*/
#include "mongo/platform/basic.h"
#include "mongo/db/ftdc/block_compressor.h"
#include <zlib.h>
#include "mongo/util/mongoutils/str.h"
namespace mongo {
StatusWith<ConstDataRange> BlockCompressor::compress(ConstDataRange source) {
z_stream stream;
int level = Z_DEFAULT_COMPRESSION;
stream.next_in = reinterpret_cast<unsigned char*>(const_cast<char*>(source.data()));
stream.avail_in = source.length();
// In compress.c in the zlib source, they recommend that the compression buffer be
// at least 0.1% larger + 12 bytes then the source length.
// We make the buffer 1% larger then the source length buffer to be on the safe side. If we are
// too small, deflate returns an error.
_buffer.resize(source.length() * 1.01 + 12);
stream.next_out = _buffer.data();
stream.avail_out = _buffer.size();
stream.zalloc = nullptr;
stream.zfree = nullptr;
stream.opaque = nullptr;
int err = deflateInit(&stream, level);
if (err != Z_OK) {
return {ErrorCodes::ZLibError, str::stream() << "deflateInit failed with " << err};
}
err = deflate(&stream, Z_FINISH);
if (err != Z_STREAM_END) {
(void)deflateEnd(&stream);
if (err != Z_OK) {
return {ErrorCodes::ZLibError, str::stream() << "deflate failed with " << err};
}
}
err = deflateEnd(&stream);
if (err != Z_OK) {
return {ErrorCodes::ZLibError, str::stream() << "deflateEnd failed with " << err};
}
return ConstDataRange(reinterpret_cast<char*>(_buffer.data()), stream.total_out);
}
StatusWith<ConstDataRange> BlockCompressor::uncompress(ConstDataRange source,
size_t uncompressedLength) {
z_stream stream;
stream.next_in = reinterpret_cast<unsigned char*>(const_cast<char*>(source.data()));
stream.avail_in = source.length();
_buffer.resize(uncompressedLength);
stream.next_out = _buffer.data();
stream.avail_out = _buffer.size();
stream.zalloc = nullptr;
stream.zfree = nullptr;
stream.opaque = nullptr;
int err = inflateInit(&stream);
if (err != Z_OK) {
return {ErrorCodes::ZLibError, str::stream() << "inflateInit failed with " << err};
}
err = inflate(&stream, Z_FINISH);
if (err != Z_STREAM_END) {
(void)inflateEnd(&stream);
if (err != Z_OK) {
return {ErrorCodes::ZLibError, str::stream() << "inflate failed with " << err};
}
}
err = inflateEnd(&stream);
if (err != Z_OK) {
return {ErrorCodes::ZLibError, str::stream() << "inflateEnd failed with " << err};
}
return ConstDataRange(reinterpret_cast<char*>(_buffer.data()), stream.total_out);
}
} // namespace mongo
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