scummvm/engines/sword25/kernel/persistenceblock.h
2011-05-12 01:16:22 +02:00

121 lines
3.1 KiB
C++

/* 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.
*
*/
/*
* This code is based on Broken Sword 2.5 engine
*
* Copyright (c) Malte Thiesen, Daniel Queteschiner and Michael Elsdoerfer
*
* Licensed under GNU GPL v2
*
*/
#ifndef SWORD25_PERSISTENCEBLOCK_H
#define SWORD25_PERSISTENCEBLOCK_H
#include "sword25/kernel/common.h"
namespace Sword25 {
class PersistenceBlock {
public:
static uint getSInt32Size() {
return sizeof(signed int) + sizeof(byte);
}
static uint getUInt32Size() {
return sizeof(uint) + sizeof(byte);
}
static uint getFloat32Size() {
return sizeof(float) + sizeof(byte);
}
static uint getBoolSize() {
return sizeof(byte) + sizeof(byte);
}
static uint getStringSize(const Common::String &string) {
return static_cast<uint>(sizeof(uint) + string.size() + sizeof(byte));
}
protected:
enum {
SINT_MARKER,
UINT_MARKER,
FLOAT_MARKER,
STRING_MARKER,
BOOL_MARKER,
BLOCK_MARKER
};
// -----------------------------------------------------------------------------
// Endianess Conversions
// -----------------------------------------------------------------------------
//
// Everything is stored in Little Endian
// Big Endian Systems will need to be byte swapped during both saving and reading of saved values
//
template<typename T>
static T convertEndianessFromSystemToStorage(T value) {
if (isBigEndian())
reverseByteOrder(&value);
return value;
}
template<typename T>
static T convertEndianessFromStorageToSystem(T value) {
if (isBigEndian())
reverseByteOrder(&value);
return value;
}
private:
static bool isBigEndian() {
uint dummy = 1;
byte *dummyPtr = reinterpret_cast<byte *>(&dummy);
return dummyPtr[0] == 0;
}
template<typename T>
static void swap(T &one, T &two) {
T temp = one;
one = two;
two = temp;
}
static void reverseByteOrder(void *ptr) {
// Reverses the byte order of the 32-bit word pointed to by Ptr
byte *charPtr = static_cast<byte *>(ptr);
swap(charPtr[0], charPtr[3]);
swap(charPtr[1], charPtr[2]);
}
};
#define CTASSERT(ex) typedef char ctassert_type[(ex) ? 1 : -1]
CTASSERT(sizeof(byte) == 1);
CTASSERT(sizeof(signed int) == 4);
CTASSERT(sizeof(uint) == 4);
CTASSERT(sizeof(float) == 4);
#undef CTASSERT
} // End of namespace Sword25
#endif