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148 lines
3.3 KiB
C++
148 lines
3.3 KiB
C++
/*
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* ungzip.cpp
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* ----------
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* Purpose: Implementation file for extracting modules from .gz archives
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* Notes : (currently none)
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* Authors: OpenMPT Devs
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* The OpenMPT source code is released under the BSD license. Read LICENSE for more details.
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*/
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#include "stdafx.h"
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#include "../common/FileReader.h"
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#include "ungzip.h"
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#if defined(MPT_WITH_ZLIB) || defined(MPT_WITH_MINIZ)
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#if defined(MPT_WITH_ZLIB)
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#include <zlib.h>
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#elif defined(MPT_WITH_MINIZ)
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#include <miniz/miniz.h>
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#endif
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#endif // MPT_WITH_ZLIB || MPT_WITH_MINIZ
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OPENMPT_NAMESPACE_BEGIN
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#if defined(MPT_WITH_ZLIB) || defined(MPT_WITH_MINIZ)
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CGzipArchive::CGzipArchive(const FileReader &file) : ArchiveBase(file)
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{
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inFile.Rewind();
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inFile.ReadStruct(header);
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// Check header data + file size
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if(header.magic1 != GZ_HMAGIC1 || header.magic2 != GZ_HMAGIC2 || header.method != GZ_HMDEFLATE || (header.flags & GZ_FRESERVED) != 0
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|| inFile.GetLength() <= sizeof(GZheader) + sizeof(GZtrailer))
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{
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return;
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}
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ArchiveFileInfo info;
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info.type = ArchiveFileType::Normal;
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contents.push_back(info);
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}
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CGzipArchive::~CGzipArchive()
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{
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return;
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}
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bool CGzipArchive::ExtractFile(std::size_t index)
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{
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if(index >= contents.size())
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{
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return false;
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}
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// Read trailer
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GZtrailer trailer;
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inFile.Seek(inFile.GetLength() - sizeof(GZtrailer));
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inFile.ReadStruct(trailer);
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// Continue reading header
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inFile.Seek(sizeof(GZheader));
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// Extra block present? (skip the extra data)
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if(header.flags & GZ_FEXTRA)
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{
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inFile.Skip(inFile.ReadUint16LE());
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}
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// Filename present? (ignore)
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if(header.flags & GZ_FNAME)
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{
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while(inFile.ReadUint8() != 0);
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}
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// Comment present? (ignore)
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if(header.flags & GZ_FCOMMENT)
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{
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while(inFile.ReadUint8() != 0);
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}
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// CRC16 present? (ignore)
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if(header.flags & GZ_FHCRC)
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{
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inFile.Skip(2);
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}
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// Well, this is a bit small when deflated.
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if(!inFile.CanRead(sizeof(GZtrailer)))
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{
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return false;
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}
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try
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{
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data.reserve(inFile.BytesLeft());
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} catch(...)
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{
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return false;
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}
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// Inflate!
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z_stream strm{};
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strm.zalloc = Z_NULL;
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strm.zfree = Z_NULL;
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strm.opaque = Z_NULL;
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strm.avail_in = 0;
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strm.next_in = Z_NULL;
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if(inflateInit2(&strm, -15) != Z_OK)
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return false;
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int retVal = Z_OK;
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uint32 crc = 0;
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auto bytesLeft = inFile.BytesLeft() - sizeof(GZtrailer);
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do
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{
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std::array<char, mpt::IO::BUFFERSIZE_SMALL> inBuffer, outBuffer;
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strm.avail_in = static_cast<uInt>(std::min(static_cast<FileReader::pos_type>(inBuffer.size()), bytesLeft));
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inFile.ReadStructPartial(inBuffer, strm.avail_in);
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strm.next_in = reinterpret_cast<Bytef *>(inBuffer.data());
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bytesLeft -= strm.avail_in;
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do
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{
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strm.avail_out = static_cast<uInt>(outBuffer.size());
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strm.next_out = reinterpret_cast<Bytef *>(outBuffer.data());
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retVal = inflate(&strm, Z_NO_FLUSH);
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const auto output = mpt::as_span(outBuffer.data(), outBuffer.data() + outBuffer.size() - strm.avail_out);
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crc = crc32(crc, reinterpret_cast<Bytef *>(output.data()), static_cast<uInt>(output.size()));
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data.insert(data.end(), output.begin(), output.end());
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} while(strm.avail_out == 0);
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} while(retVal == Z_OK && bytesLeft);
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inflateEnd(&strm);
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// Everything went OK? Check return code, number of written bytes and CRC32.
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return retVal == Z_STREAM_END && trailer.isize == static_cast<uint32>(strm.total_out) && trailer.crc32_ == crc;
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}
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#endif // MPT_WITH_ZLIB || MPT_WITH_MINIZ
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OPENMPT_NAMESPACE_END
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