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Diffstat (limited to 'engines/lure/disk.cpp')
| -rw-r--r-- | engines/lure/disk.cpp | 174 |
1 files changed, 174 insertions, 0 deletions
diff --git a/engines/lure/disk.cpp b/engines/lure/disk.cpp new file mode 100644 index 0000000000..e996ff6ecc --- /dev/null +++ b/engines/lure/disk.cpp @@ -0,0 +1,174 @@ +/* ScummVM - Scumm Interpreter + * Copyright (C) 2005-2006 The ScummVM project + * + * 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/stdafx.h" +#include "common/file.h" +#include "common/util.h" +#include "common/scummsys.h" + +#include "lure/disk.h" +#include "lure/luredefs.h" + +namespace Lure { + +static Disk *int_disk = NULL; + +Disk &Disk::getReference() { + return *int_disk; +} + +Disk::Disk(const Common::String &gameDataPath) { + _gameDataPath = gameDataPath; + _fileNum = 0xff; + _fileHandle = NULL; + int_disk = this; +} + +Disk::~Disk() { + if (_fileHandle) delete _fileHandle; + int_disk = NULL; +} + +uint8 Disk::indexOf(uint16 id, bool suppressError) { + // Make sure the correct file is open - the upper two bits of the Id give the file number. Note + // that an extra check is done for the upper byte of the Id being 0x3f, which is the Id range + // I use for lure.dat resources, which are resources extracted from the lure.exe executable + uint8 entryFileNum = ((id>>8) == 0x3f) ? 0 : ((id >> 14) & 3) + 1; + openFile(entryFileNum); + + // Find the correct entry in the list based on the Id + for (int entryIndex=0; entryIndex<NUM_ENTRIES_IN_HEADER; ++entryIndex) { + if (_entries[entryIndex].id == HEADER_ENTRY_UNUSED_ID) break; + else if (_entries[entryIndex].id == id) return entryIndex; + } + + if (suppressError) return 0xff; + error("Could not find entry Id #%d in file %sdisk%d.vga", id, _gameDataPath.c_str(), _fileNum); +} + +void Disk::openFile(uint8 fileNum) { + // Validate that the file number is correct + if (fileNum > 4) + error("Invalid file number specified - %d", fileNum); + + // Only load up the new file if the current file number has changed + if (fileNum == _fileNum) return; + + // Delete any existing open file handle + if (_fileNum != 0xff) delete _fileHandle; + _fileNum = fileNum; + + // Open up the the new file + _fileHandle = new Common::File(); + + char sFilename[10]; + if (_fileNum == 0) + strcpy(sFilename, SUPPORT_FILENAME); + else + sprintf(sFilename, "disk%d.vga", _fileNum); + + _fileHandle->open(sFilename); + if (!_fileHandle->isOpen()) + error("Could not open %s%s", _gameDataPath.c_str(), sFilename); + + // Validate the header + char buffer[7]; + uint32 bytesRead; + + bytesRead = _fileHandle->read(buffer, 6); + buffer[6] = '\0'; + if (strcmp(buffer, HEADER_IDENT_STRING) != 0) + error("The file %s%s was not a valid VGA file", _gameDataPath.c_str(), sFilename); + + uint16 fileFileNum = _fileHandle->readUint16BE(); + if (fileFileNum != _fileNum) + error("The file %s%s was not the correct file number", _gameDataPath.c_str(), sFilename); + + // Read in the header entries + uint32 headerSize = sizeof(FileEntry) * NUM_ENTRIES_IN_HEADER; + if (_fileHandle->read(_entries, headerSize) != headerSize) + error("The file %s%s had a corrupted header", _gameDataPath.c_str(), sFilename); + +#ifdef SCUMM_BIG_ENDIAN + // Process the read in header list to convert to big endian + for (int i = 0; i < NUM_ENTRIES_IN_HEADER; ++i) { + _entries[i].id = FROM_LE_16(_entries[i].id); + _entries[i].size = FROM_LE_16(_entries[i].size); + _entries[i].offset = FROM_LE_16(_entries[i].offset); + } +#endif +} + +uint32 Disk::getEntrySize(uint16 id) { + // Get the index of the resource, if necessary opening the correct file + uint8 index = indexOf(id); + + // Calculate the offset and size of the entry + uint32 size = (uint32) _entries[index].size; + if (_entries[index].sizeExtension) size += 0x10000; + + return size; +} + +MemoryBlock *Disk::getEntry(uint16 id) +{ + // Get the index of the resource, if necessary opening the correct file + uint8 index = indexOf(id); + + // Calculate the offset and size of the entry + uint32 size = (uint32) _entries[index].size; + if (_entries[index].sizeExtension) size += 0x10000; + uint32 offset = (uint32) _entries[index].offset * 0x20; + + MemoryBlock *result = Memory::allocate(size); + _fileHandle->seek(offset, SEEK_SET); + _fileHandle->read(result->data(), size); + return result; +} + +bool Disk::exists(uint16 id) { + // Get the index of the resource, if necessary opening the correct file + uint8 index = indexOf(id, true); + return (index != 0xff); +} + +uint8 Disk::numEntries() { + if (_fileNum == 0) + error("No file is currently open"); + + // Figure out how many entries there are by count until an unused entry is found + for (byte entryIndex = 0; entryIndex < NUM_ENTRIES_IN_HEADER; ++entryIndex) + if (_entries[entryIndex].id == HEADER_ENTRY_UNUSED_ID) return entryIndex; + + return NUM_ENTRIES_IN_HEADER; +} + +FileEntry *Disk::getIndex(uint8 entryIndex) { + if (_fileNum == 0) + error("No file is currently open"); + if ((entryIndex >= NUM_ENTRIES_IN_HEADER) || (_entries[entryIndex].id == HEADER_ENTRY_UNUSED_ID)) + error("There is no entry at the specified index"); + + return &_entries[entryIndex]; +} + +} // end of namespace Lure |