Introduce ReadStream and WriteStream (as explained in my File class design mails on scummvm-devel)

svn-id: r13595

common/file.cpp

@@ -273,45 +273,6 @@ uint32 File::read(void *ptr, uint32 len) {
 	return real_len;
 }
 
-byte File::readByte() {
-	byte b;
-
-	if (_handle == NULL) {
-		error("File is not open!");
-		return 0;
-	}
-
-	if (fread(&b, 1, 1, _handle) != 1) {
-		clearerr(_handle);
-		_ioFailed = true;
-	}
-	return b ^ _encbyte;
-}
-
-uint16 File::readUint16LE() {
-	uint16 a = readByte();
-	uint16 b = readByte();
-	return a | (b << 8);
-}
-
-uint32 File::readUint32LE() {
-	uint32 a = readUint16LE();
-	uint32 b = readUint16LE();
-	return (b << 16) | a;
-}
-
-uint16 File::readUint16BE() {
-	uint16 b = readByte();
-	uint16 a = readByte();
-	return a | (b << 8);
-}
-
-uint32 File::readUint32BE() {
-	uint32 b = readUint16BE();
-	uint32 a = readUint16BE();
-	return (b << 16) | a;
-}
-
 uint32 File::write(const void *ptr, uint32 len) {
 	byte *tmp = 0;
 	
@@ -345,36 +306,3 @@ uint32 File::write(const void *ptr, uint32 len) {
 
 	return len;
 }
-
-void File::writeByte(byte value) {
-	value ^= _encbyte;
-
-	if (_handle == NULL) {
-		error("File is not open!");
-	}
-
-	if (fwrite(&value, 1, 1, _handle) != 1) {
-		clearerr(_handle);
-		_ioFailed = true;
-	}
-}
-
-void File::writeUint16LE(uint16 value) {
-	writeByte((byte)(value & 0xff));
-	writeByte((byte)(value >> 8));
-}
-
-void File::writeUint32LE(uint32 value) {
-	writeUint16LE((uint16)(value & 0xffff));
-	writeUint16LE((uint16)(value >> 16));
-}
-
-void File::writeUint16BE(uint16 value) {
-	writeByte((byte)(value >> 8));
-	writeByte((byte)(value & 0xff));
-}
-
-void File::writeUint32BE(uint32 value) {
-	writeUint16BE((uint16)(value >> 16));
-	writeUint16BE((uint16)(value & 0xffff));
-}

common/file.h

@@ -25,8 +25,9 @@
 #include "stdafx.h"
 #include "common/scummsys.h"
 #include "common/str.h"
+#include "common/stream.h"
 
-class File {
+class File : public Common::ReadStream, public Common::WriteStream {
 private:
 
 	FILE * _handle;
@@ -60,17 +61,8 @@ public:
 	const char *name() const { return _name; }
 	void seek(int32 offs, int whence = SEEK_SET);
 	uint32 read(void *ptr, uint32 size);
-	byte readByte();
-	uint16 readUint16LE();
-	uint32 readUint32LE();
-	uint16 readUint16BE();
-	uint32 readUint32BE();
 	uint32 write(const void *ptr, uint32 size);
-	void writeByte(byte value);
+
-	void writeUint16LE(uint16 value);
-	void writeUint32LE(uint32 value);
-	void writeUint16BE(uint16 value);
-	void writeUint32BE(uint32 value);
 	void setEnc(byte value) { _encbyte = value; }
 };
 

common/module.mk

@@ -6,6 +6,7 @@ MODULE_OBJS := \
 	common/md5.o \
 	common/scaler.o \
 	common/str.o \
+	common/stream.o \
 	common/timer.o \
 	common/util.o \
 	common/savefile.o \

common/savefile.cpp

@@ -23,6 +23,9 @@
 #include "common/util.h"
 #include "common/savefile.h"
 
+#include <stdio.h>
+#include <string.h>
+
 #ifdef USE_ZLIB
 #include <zlib.h>
 #endif
@@ -31,66 +34,10 @@ uint32 SaveFile::read(void *ptr, uint32 size) {
 	return fread(ptr, 1, size);
 }
 
-byte SaveFile::readByte() {
-	byte b;
-	// TODO: Proper error handling
-	if (fread(&b, 1, 1) != 1)
-		return 0;
-	return b;
-}
-
-uint16 SaveFile::readUint16LE() {
-	uint16 a = readByte();
-	uint16 b = readByte();
-	return a | (b << 8);
-}
-
-uint32 SaveFile::readUint32LE() {
-	uint32 a = readUint16LE();
-	uint32 b = readUint16LE();
-	return (b << 16) | a;
-}
-
-uint16 SaveFile::readUint16BE() {
-	uint16 b = readByte();
-	uint16 a = readByte();
-	return a | (b << 8);
-}
-
-uint32 SaveFile::readUint32BE() {
-	uint32 b = readUint16BE();
-	uint32 a = readUint16BE();
-	return (b << 16) | a;
-}
-
 uint32 SaveFile::write(const void *ptr, uint32 size) {
 	return fwrite(ptr, 1, size);
 }
 
-void SaveFile::writeByte(byte value) {
-	fwrite(&value, 1, 1);
-}
-
-void SaveFile::writeUint16LE(uint16 value) {
-	writeByte((byte)(value & 0xff));
-	writeByte((byte)(value >> 8));
-}
-
-void SaveFile::writeUint32LE(uint32 value) {
-	writeUint16LE((uint16)(value & 0xffff));
-	writeUint16LE((uint16)(value >> 16));
-}
-
-void SaveFile::writeUint16BE(uint16 value) {
-	writeByte((byte)(value >> 8));
-	writeByte((byte)(value & 0xff));
-}
-
-void SaveFile::writeUint32BE(uint32 value) {
-	writeUint16BE((uint16)(value >> 16));
-	writeUint16BE((uint16)(value & 0xffff));
-}
-
 
 class StdioSaveFile : public SaveFile {
 private:

common/savefile.h

@@ -25,28 +25,16 @@
 
 #include "stdafx.h"
 #include "common/scummsys.h"
-
+#include "common/stream.h"
-#include <stdio.h>
-#include <string.h>
 
 
-class SaveFile {
+class SaveFile : public Common::ReadStream, public Common::WriteStream {
 public:
 	virtual ~SaveFile() {}
 
 	/* Compatible with File API */
 	uint32 read(void *ptr, uint32 size);
-	byte readByte();
-	uint16 readUint16LE();
-	uint32 readUint32LE();
-	uint16 readUint16BE();
-	uint32 readUint32BE();
 	uint32 write(const void *ptr, uint32 size);
-	void writeByte(byte value);
-	void writeUint16LE(uint16 value);
-	void writeUint32LE(uint32 value);
-	void writeUint16BE(uint16 value);
-	void writeUint32BE(uint32 value);
 
 	virtual bool isOpen() const = 0;
 

common/stream.cpp

@@ -0,0 +1,86 @@
+/* ScummVM - Scumm Interpreter
+ * Copyright (C) 2002-2004 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., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+ *
+ * $Header$
+ *
+ */
+
+#include "stdafx.h"
+#include "common/stream.h"
+
+namespace Common {
+
+/* TODO:
+ * - The ReadStream / WriteStream should provide some error handling
+ */
+
+byte ReadStream::readByte() {
+	byte b = 0;
+	read(&b, 1);
+	return b;
+}
+
+uint16 ReadStream::readUint16LE() {
+	uint16 a = readByte();
+	uint16 b = readByte();
+	return a | (b << 8);
+}
+
+uint32 ReadStream::readUint32LE() {
+	uint32 a = readUint16LE();
+	uint32 b = readUint16LE();
+	return (b << 16) | a;
+}
+
+uint16 ReadStream::readUint16BE() {
+	uint16 b = readByte();
+	uint16 a = readByte();
+	return a | (b << 8);
+}
+
+uint32 ReadStream::readUint32BE() {
+	uint32 b = readUint16BE();
+	uint32 a = readUint16BE();
+	return (b << 16) | a;
+}
+
+
+void WriteStream::writeByte(byte value) {
+	write(&value, 1);
+}
+
+void WriteStream::writeUint16LE(uint16 value) {
+	writeByte((byte)(value & 0xff));
+	writeByte((byte)(value >> 8));
+}
+
+void WriteStream::writeUint32LE(uint32 value) {
+	writeUint16LE((uint16)(value & 0xffff));
+	writeUint16LE((uint16)(value >> 16));
+}
+
+void WriteStream::writeUint16BE(uint16 value) {
+	writeByte((byte)(value >> 8));
+	writeByte((byte)(value & 0xff));
+}
+
+void WriteStream::writeUint32BE(uint32 value) {
+	writeUint16BE((uint16)(value >> 16));
+	writeUint16BE((uint16)(value & 0xffff));
+}
+
+}	// End of namespace Common

common/stream.h

@@ -0,0 +1,123 @@
+/* ScummVM - Scumm Interpreter
+ * Copyright (C) 2001  Ludvig Strigeus
+ * Copyright (C) 2001/2002 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., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+ *
+ * $Header$
+ *
+ */
+
+#ifndef COMMON_STREAM_H
+#define COMMON_STREAM_H
+
+#include "stdafx.h"
+#include "common/scummsys.h"
+
+
+namespace Common {
+
+class WriteStream {
+public:
+	virtual uint32 write(const void *ptr, uint32 size) = 0;
+
+	// The remaining methods all have default implementations
+
+	void writeByte(byte value);
+
+	void writeUint16LE(uint16 value);
+	void writeUint32LE(uint32 value);
+
+	void writeUint16BE(uint16 value);
+	void writeUint32BE(uint32 value);
+
+/*
+	void writeSint16LE(int16 value);
+	void writeSint32LE(int32 value);
+
+	void writeSint16BE(int16 value);
+	void writeSint32BE(int32 value);
+*/
+};
+
+
+class ReadStream {
+public:
+	virtual uint32 read(void *ptr, uint32 size) = 0;
+
+	// The remaining methods all have default implementations
+
+	byte readByte();
+
+	uint16 readUint16LE();
+	uint32 readUint32LE();
+
+	uint16 readUint16BE();
+	uint32 readUint32BE();
+
+/*
+	int16 readSint16LE();
+	int32 readSint32LE();
+
+	int16 readSint16BE();
+	int32 readSint32BE();
+*/
+};
+
+/**
+ * XORReadStream is a wrapper around an arbitrary other ReadStream,
+ * which 'decrypts' the data being read by XORing all data bytes with the given
+ * encryption 'key'.
+ */
+class XORReadStream : public ReadStream {
+private:
+	byte _encbyte;
+	ReadStream *_realStream;
+public:
+	XORReadStream(ReadStream *in, byte enc = 0) : _realStream(in), _encbyte(enc) {}
+	void setEnc(byte value) { _encbyte = value; }
+
+	uint32 read(void *ptr, uint32 size) {
+		uint32 len = _realStream->read(ptr, size);
+		if (_encbyte) {
+			byte *p = (byte *)ptr;
+			byte *end = p + len;
+			while (p < end)
+				*p++ ^= _encbyte;
+		}
+		return len;
+	}
+};
+
+class MemoryReadStream : public ReadStream {
+private:
+	const byte *_ptr;
+	uint32 _size;
+public:
+	MemoryReadStream(const byte *ptr, uint32 size) : _ptr(ptr), _size(size) {}
+
+	uint32 read(void *ptr, uint32 size) {
+		if (size > _size)
+			size = _size;
+		memcpy(ptr, _ptr, size);
+		_size -= size;
+		_ptr += size;
+		return size;
+	}
+};
+
+}	// End of namespace Common
+
+#endif