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Diffstat (limited to 'engines/draci/barchive.cpp')
| -rw-r--r-- | engines/draci/barchive.cpp | 201 |
1 files changed, 201 insertions, 0 deletions
diff --git a/engines/draci/barchive.cpp b/engines/draci/barchive.cpp new file mode 100644 index 0000000000..f813222552 --- /dev/null +++ b/engines/draci/barchive.cpp @@ -0,0 +1,201 @@ +/* ScummVM - Graphic Adventure Engine + * + * ScummVM is the legal property of its developers, whose names + * are too numerous to list here. Please refer to the COPYRIGHT + * file distributed with this source distribution. + * + * 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; either version 2 + * of the License, or (at your option) any later version. + + * 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, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. + * + * $URL$ + * $Id$ + * + */ + +#include "common/debug.h" +#include "common/file.h" +#include "common/str.h" +#include "common/stream.h" + +#include "draci/barchive.h" +#include "draci/draci.h" + +namespace Draci { + +const char BArchive::_magicNumber[] = "BAR!"; + +/** + * @brief BArchive open method + * @param path Path to input file + * + * Opens a BAR (Bob's Archiver) archive, which is the game's archiving format. + * BAR archives have a .DFW file extension, due to an unused historical interface. + * + * archive format: header, + * file0, file1, ... + * footer + * header format: [4 bytes] magic number "BAR!" + * [uint16LE] file count (number of archived streams), + * [uint32LE] footer offset from start of file + * file<N> format: [2 bytes] compressed length + * [2 bytes] original length + * [1 byte] compression type + * [1 byte] CRC + * footer format: [array of uint32LE] offsets of individual files from start of archive + * (last entry is footer offset again) + */ + +void BArchive::openArchive(const Common::String &path) { + byte buf[4]; + byte *footer; + uint32 footerOffset, footerSize; + Common::File f; + + // Close previously opened archive (if any) + closeArchive(); + + debugC(5, kDraciGeneralDebugLevel, "Loading BAR archive %s:", + path.c_str()); + + f.open(path); + if (f.isOpen()) { + debugC(5, kDraciGeneralDebugLevel, "Success"); + } else { + debugC(5, kDraciGeneralDebugLevel, "Error"); + return; + } + + // Save path for reading in files later on + _path = path; + + // Read archive header + debugC(5, kDraciGeneralDebugLevel, "Checking magic number:"); + + f.read(buf, 4); + if (memcmp(buf, _magicNumber, 4) == 0) { + debugC(5, kDraciGeneralDebugLevel, "Success"); + } else { + debugC(5, kDraciGeneralDebugLevel, "Error"); + f.close(); + return; + } + + _fileCount = f.readUint16LE(); + footerOffset = f.readUint32LE(); + footerSize = f.size() - footerOffset; + + debugC(5, kDraciGeneralDebugLevel, "Archive info: %d files, %d data bytes", + _fileCount, footerOffset - _archiveHeaderSize); + + // Read in footer + footer = new byte[footerSize]; + f.seek(footerOffset); + f.read(footer, footerSize); + Common::MemoryReadStream reader(footer, footerSize); + + // Read in file headers, but do not read the actual data yet + // The data will be read on demand to save memory + _files = new BAFile[_fileCount]; + + for (unsigned int i = 0; i < _fileCount; i++) { + uint32 fileOffset; + + fileOffset = reader.readUint32LE(); + f.seek(fileOffset); // Seek to next file in archive + f.readUint16LE(); // Compressed size, not used + _files[i]._length = f.readUint16LE(); // Original size + _files[i]._offset = fileOffset; + + assert(f.readByte() == 0 && + "Compression type flag is non-zero (file is compressed)"); + + _files[i]._crc = f.readByte(); // CRC checksum of the file + _files[i]._data = NULL; // File data will be read in on demand + } + + // Last footer item should be equal to footerOffset + assert(reader.readUint32LE() == footerOffset && "Footer offset mismatch"); + + f.close(); +} + +/** + * @brief BArchive close method + * + * Closes the currently opened archive. It can be called explicitly to + * free up memory. + */ +void BArchive::closeArchive(void) { + if (!_files) { + return; + } + + for (unsigned int i = 0; i < _fileCount; ++i) { + if (_files[i]._data) { + delete _files[i]._data; + } + } + + delete[] _files; + + _files = NULL; + _fileCount = 0; +} + +BAFile *BArchive::operator[](unsigned int i) const { + Common::File f; + + // Check whether requested file exists + if (i >= _fileCount) { + return NULL; + } + + debugC(5, kDraciGeneralDebugLevel, "Accessing file %d from archive %s", + i, _path.c_str()); + + // Check if file has already been opened and return that + if (_files[i]._data) { + return _files + i; + } + + // Else open archive and read in requested file + f.open(_path); + if (f.isOpen()) { + debugC(5, kDraciGeneralDebugLevel, "Success"); + } else { + debugC(5, kDraciGeneralDebugLevel, "Error"); + return NULL; + } + + // Read in the file (without the file header) + f.seek(_files[i]._offset + _fileHeaderSize); + _files[i]._data = new byte[_files[i]._length]; + f.read(_files[i]._data, _files[i]._length); + + // Calculate CRC + byte tmp = 0; + for (unsigned int j = 0; j < _files[i]._length; j++) { + tmp ^= _files[i]._data[j]; + } + + debugC(5, kDraciGeneralDebugLevel, "Read in file %d", i); + assert(tmp == _files[i]._crc && "CRC checksum mismatch"); + + return _files + i; +} + +} // End of namespace Draci + + + |