ADL: Add file-based disk access class

engines/adl/disk.cpp

@@ -21,6 +21,7 @@
  */
 
 #include "common/stream.h"
+#include "common/substream.h"
 
 #include "adl/disk.h"
 
@@ -87,4 +88,24 @@ bool DiskImage_DSK::open(const Common::String &filename) {
 	return true;
 }
 
+Common::SeekableReadStream *FilesDataBlock::createReadStream() const {
+	return _files->createReadStream(_filename, _offset);
+}
+
+const DataBlockPtr PlainFiles::getDataBlock(const Common::String &filename, uint offset) const {
+	return Common::SharedPtr<FilesDataBlock>(new FilesDataBlock(this, filename, offset));
+}
+
+Common::SeekableReadStream *PlainFiles::createReadStream(const Common::String &filename, uint offset) const {
+	Common::File *f(new Common::File());
+
+	if (!f->open(filename))
+		error("Failed to open '%s'", filename.c_str());
+
+	if (offset == 0)
+		return f;
+	else
+		return new Common::SeekableSubReadStream(f, offset, f->size(), DisposeAfterUse::YES);
+}
+
 } // End of namespace Adl

engines/adl/disk.h

@@ -43,6 +43,33 @@ public:
 
 typedef Common::SharedPtr<DataBlock> DataBlockPtr;
 
+class Files {
+public:
+	virtual ~Files() { }
+
+	virtual const DataBlockPtr getDataBlock(const Common::String &filename, uint offset) const = 0;
+	virtual Common::SeekableReadStream *createReadStream(const Common::String &filename, uint offset) const = 0;
+};
+
+class FilesDataBlock : public DataBlock {
+public:
+	FilesDataBlock(const Files *files, const Common::String &filename, uint offset) : _files(files), _filename(filename), _offset(offset) { }
+
+	bool isValid() const { return true; }
+	Common::SeekableReadStream *createReadStream() const;
+
+private:
+	const Common::String _filename;
+	uint _offset;
+	const Files *_files;
+};
+
+class PlainFiles : public Files {
+public:
+	const DataBlockPtr getDataBlock(const Common::String &filename, uint offset = 0) const;
+	Common::SeekableReadStream *createReadStream(const Common::String &filename, uint offset = 0) const;
+};
+
 class DiskImage {
 public:
 	DiskImage();