ADL: Add disk format abstraction

3 files changed, 172 insertions, 0 deletions

diff --git a/engines/adl/disk.cpp b/engines/adl/disk.cpp
new file mode 100644
index 0000000000..b91efec1f1
--- /dev/null
+++ b/engines/adl/disk.cpp
@@ -0,0 +1,90 @@
+/* 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.
+ *
+ */
+
+#include "common/stream.h"
+
+#include "adl/disk.h"
+
+namespace Adl {
+
+DiskImage::DiskImage() :
+		_tracks(0),
+		_sectorsPerTrack(0),
+		_bytesPerSector(0) {
+	_f = new Common::File();
+}
+
+DiskImage::~DiskImage() {
+	delete _f;
+}
+
+DiskImageDataBlock::DiskImageDataBlock(const DiskImage *disk, uint track, uint sector, uint offset, uint size) :
+		_track(track),
+		_sector(sector),
+		_offset(offset),
+		_size(size),
+		_disk(disk) { }
+
+bool DiskImageDataBlock::isValid() const {
+	return _track != 0 || _sector != 0 || _offset != 0 || _size != 0;
+}
+
+Common::SeekableReadStream *DiskImageDataBlock::createReadStream() const {
+	return _disk->createReadStream(_track, _sector, _offset, _size);
+}
+
+// .DSK disk image - 35 tracks, 16 sectors per track, 256 bytes per sector, raw sector layout
+const DataBlockPtr DiskImage_DSK::getDataBlock(uint track, uint sector, uint offset, uint size) const {
+	return Common::SharedPtr<DiskImageDataBlock>(new DiskImageDataBlock(this, track, sector, offset, size));
+}
+
+Common::SeekableReadStream *DiskImage_DSK::createReadStream(uint track, uint sector, uint offset, uint size) const {
+	_f->seek((track * _sectorsPerTrack + sector) * _bytesPerSector + offset);
+	Common::SeekableReadStream *stream = _f->readStream(size * _bytesPerSector + _bytesPerSector - offset);
+
+	if (_f->eos() || _f->err())
+		error("Error reading disk image");
+
+	return stream;
+}
+
+bool DiskImage_DSK::open(const Common::String &filename) {
+	assert(!_f->isOpen());
+
+	if (!_f->open(filename))
+		return false;
+
+	uint filesize = _f->size();
+	switch (filesize) {
+	case 143360:
+		_tracks = 35;
+		_sectorsPerTrack = 16;
+		_bytesPerSector = 256;
+		break;
+	default:
+		warning("Unrecognized disk image '%s' of size %d bytes", filename.c_str(), filesize);
+	}
+
+	return true;
+}
+
+} // End of namespace Adl
diff --git a/engines/adl/disk.h b/engines/adl/disk.h
new file mode 100644
index 0000000000..0bf57c7661
--- /dev/null
+++ b/engines/adl/disk.h
@@ -0,0 +1,81 @@
+/* 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.
+ *
+ */
+
+#include "common/ptr.h"
+#include "common/file.h"
+
+#ifndef ADL_DISK_H
+#define ADL_DISK_H
+
+namespace Common {
+class SeekableReadStream;
+class String;
+}
+
+namespace Adl {
+
+class DataBlock {
+public:
+	virtual ~DataBlock() { }
+
+	virtual bool isValid() const = 0;
+	virtual Common::SeekableReadStream *createReadStream() const = 0;
+};
+
+typedef Common::SharedPtr<DataBlock> DataBlockPtr;
+
+class DiskImage {
+public:
+	DiskImage();
+	virtual ~DiskImage();
+
+	virtual bool open(const Common::String &filename) = 0;
+	virtual const DataBlockPtr getDataBlock(uint track, uint sector, uint offset, uint size) const = 0;
+	virtual Common::SeekableReadStream *createReadStream(uint track, uint sector, uint offset, uint size) const = 0;
+
+protected:
+	Common::File *_f;
+	uint _tracks, _sectorsPerTrack, _bytesPerSector;
+};
+
+class DiskImageDataBlock : public DataBlock {
+public:
+	DiskImageDataBlock(const DiskImage *disk, uint track, uint sector, uint offset, uint size);
+
+	bool isValid() const;
+	Common::SeekableReadStream *createReadStream() const;
+
+private:
+	uint _track, _sector, _offset, _size;
+	const DiskImage *_disk;
+};
+
+class DiskImage_DSK : public DiskImage {
+public:
+	bool open(const Common::String &filename);
+	const DataBlockPtr getDataBlock(uint track, uint sector, uint offset, uint size) const;
+	Common::SeekableReadStream *createReadStream(uint track, uint sector, uint offset = 0, uint size = 0) const;
+};
+
+} // End of namespace Adl
+
+#endif
diff --git a/engines/adl/module.mk b/engines/adl/module.mk
index 7599957806..661d1b1991 100644
--- a/engines/adl/module.mk
+++ b/engines/adl/module.mk
@@ -4,6 +4,7 @@ MODULE_OBJS := \
 	adl.o \
 	adl_v2.o \
 	detection.o \
+	disk.o \
 	display.o \
 	graphics.o \
 	graphics_v1.o \