/* Scumm Tools
 * Copyright (C) 2004-2006  The ScummVM Team
 *
 * 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: https://scummvm.svn.sourceforge.net/svnroot/scummvm/tools/tags/release-0-10-0/utils/stream.h $
 * $Id: stream.h 23138 2006-06-15 15:44:06Z h00ligan $
 *
 */

#ifndef COMMON_STREAM_H
#define COMMON_STREAM_H

#include "../util.h"

namespace Common {

/**
 * Virtual base class for both ReadStream and WriteStream.
 */
class Stream {
public:
	virtual ~Stream() {}

	/**
	 * Returns true if any I/O failure occured.
	 * This flag is never cleared automatically. In order to clear it,
	 * client code has to call clearIOFailed() explicitly.
	 *
	 * @todo Instead of returning a plain bool, maybe we should define
	 *       a list of error codes which can be returned here.
	 */
	virtual bool ioFailed() const { return false; }

	/**
	 * Reset the I/O error status.
	 */
	virtual void clearIOFailed() {}
};


/**
 * Generic interface for a readable data stream.
 */
class ReadStream : virtual public Stream {
public:
	/**
	 * Returns true if the end of the stream has been reached.
	 */
	virtual bool eos() const = 0;

	/**
	 * Read data from the stream. Subclasses must implement this
	 * method; all other read methods are implemented using it.
	 *
	 * @param dataPtr	pointer to a buffer into which the data is read
	 * @param dataSize	number of bytes to be read
	 * @return the number of bytes which were actually read.
	 */
	virtual uint32 read(void *dataPtr, uint32 dataSize) = 0;


	// The remaining methods all have default implementations; subclasses
	// need not (and should not) overload them.

	byte readByte() {
		byte b = 0;
		read(&b, 1);
		return b;
	}

	int8 readSByte() {
		int8 b = 0;
		read(&b, 1);
		return b;
	}

	uint16 readUint16LE() {
		uint16 a = readByte();
		uint16 b = readByte();
		return a | (b << 8);
	}

	uint32 readUint32LE() {
		uint32 a = readUint16LE();
		uint32 b = readUint16LE();
		return (b << 16) | a;
	}

	uint16 readUint16BE() {
		uint16 b = readByte();
		uint16 a = readByte();
		return a | (b << 8);
	}

	uint32 readUint32BE() {
		uint32 b = readUint16BE();
		uint32 a = readUint16BE();
		return (b << 16) | a;
	}

	int16 readSint16LE() {
		return (int16)readUint16LE();
	}

	int32 readSint32LE() {
		return (int32)readUint32LE();
	}

	int16 readSint16BE() {
		return (int16)readUint16BE();
	}

	int32 readSint32BE() {
		return (int32)readUint32BE();
	}
};


/**
 * Interface for a seekable & readable data stream.
 *
 * @todo We really need better error handling here!
 *       Like seek should somehow indicate whether it failed.
 */
class SeekableReadStream : public ReadStream {
public:

	virtual uint32 pos() const = 0;
	virtual uint32 size() const = 0;

	virtual void seek(int32 offset, int whence = SEEK_SET) = 0;
	
	void skip(uint32 offset) { seek(offset, SEEK_CUR); }
};


}	// End of namespace Common

#endif