pollymc/launcher/GZip.cpp

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// SPDX-License-Identifier: GPL-3.0-only
/*
* PolyMC - Minecraft Launcher
* Copyright (C) 2022 Sefa Eyeoglu <contact@scrumplex.net>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, version 3.
*
* 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*
* This file incorporates work covered by the following copyright and
* permission notice:
*
* Copyright 2013-2021 MultiMC Contributors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "GZip.h"
#include <zlib.h>
#include <QByteArray>
bool GZip::unzip(const QByteArray &compressedBytes, QByteArray &uncompressedBytes)
{
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if (compressedBytes.size() == 0)
{
uncompressedBytes = compressedBytes;
return true;
}
unsigned uncompLength = compressedBytes.size();
uncompressedBytes.clear();
uncompressedBytes.resize(uncompLength);
z_stream strm;
memset(&strm, 0, sizeof(strm));
strm.next_in = (Bytef *)compressedBytes.data();
strm.avail_in = compressedBytes.size();
bool done = false;
if (inflateInit2(&strm, (16 + MAX_WBITS)) != Z_OK)
{
return false;
}
int err = Z_OK;
while (!done)
{
// If our output buffer is too small
if (strm.total_out >= uncompLength)
{
uncompressedBytes.resize(uncompLength * 2);
uncompLength *= 2;
}
strm.next_out = reinterpret_cast<Bytef *>((uncompressedBytes.data() + strm.total_out));
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strm.avail_out = uncompLength - strm.total_out;
// Inflate another chunk.
err = inflate(&strm, Z_SYNC_FLUSH);
if (err == Z_STREAM_END)
done = true;
else if (err != Z_OK)
{
break;
}
}
if (inflateEnd(&strm) != Z_OK || !done)
{
return false;
}
uncompressedBytes.resize(strm.total_out);
return true;
}
bool GZip::zip(const QByteArray &uncompressedBytes, QByteArray &compressedBytes)
{
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if (uncompressedBytes.size() == 0)
{
compressedBytes = uncompressedBytes;
return true;
}
unsigned compLength = qMin(uncompressedBytes.size(), 16);
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compressedBytes.clear();
compressedBytes.resize(compLength);
z_stream zs;
memset(&zs, 0, sizeof(zs));
if (deflateInit2(&zs, Z_DEFAULT_COMPRESSION, Z_DEFLATED, (16 + MAX_WBITS), 8, Z_DEFAULT_STRATEGY) != Z_OK)
{
return false;
}
zs.next_in = (Bytef*)uncompressedBytes.data();
zs.avail_in = uncompressedBytes.size();
int ret;
compressedBytes.resize(uncompressedBytes.size());
unsigned offset = 0;
unsigned temp = 0;
do
{
auto remaining = compressedBytes.size() - offset;
if(remaining < 1)
{
compressedBytes.resize(compressedBytes.size() * 2);
}
zs.next_out = reinterpret_cast<Bytef*>((compressedBytes.data() + offset));
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temp = zs.avail_out = compressedBytes.size() - offset;
ret = deflate(&zs, Z_FINISH);
offset += temp - zs.avail_out;
} while (ret == Z_OK);
compressedBytes.resize(offset);
if (deflateEnd(&zs) != Z_OK)
{
return false;
}
if (ret != Z_STREAM_END)
{
return false;
}
return true;
}