Files @ r15577:a61e44bed2f3
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Location: cpp/openttd-patchpack/source/src/saveload/oldloader.h

rubidium
(svn r20247) -Fix: when it is known the loading an old savegame is going to fail, bail out immediately (using an exception) instead of going on until e.g. the expected number of byte is read
/* $Id$ */

/*
 * This file is part of OpenTTD.
 * OpenTTD 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, version 2.
 * OpenTTD 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 OpenTTD. If not, see <http://www.gnu.org/licenses/>.
 */

/** @file oldloader.h Declarations of strctures and function used in loader of old savegames */

#ifndef OLDLOADER_H
#define OLDLOADER_H

#include "saveload.h"
#include "../tile_type.h"

static const uint BUFFER_SIZE = 4096;
static const uint OLD_MAP_SIZE = 256 * 256;

struct LoadgameState {
	FILE *file;

	uint chunk_size;

	bool decoding;
	byte decode_char;

	uint buffer_count;
	uint buffer_cur;
	byte buffer[BUFFER_SIZE];

	uint total_read;
};

/* OldChunk-Type */
enum OldChunkType {
	OC_SIMPLE    = 0,
	OC_NULL      = 1,
	OC_CHUNK     = 2,
	OC_ASSERT    = 3,
	/* 4 bits allocated (16 max) */

	OC_TTD       = 1 << 4, ///< chunk is valid ONLY for TTD savegames
	OC_TTO       = 1 << 5, ///< -//- TTO (default is neither of these)
	/* 4 bits allocated */

	OC_VAR_I8    = 1 << 8,
	OC_VAR_U8    = 2 << 8,
	OC_VAR_I16   = 3 << 8,
	OC_VAR_U16   = 4 << 8,
	OC_VAR_I32   = 5 << 8,
	OC_VAR_U32   = 6 << 8,
	OC_VAR_I64   = 7 << 8,
	OC_VAR_U64   = 8 << 8,
	/* 8 bits allocated (256 max) */

	OC_FILE_I8   = 1 << 16,
	OC_FILE_U8   = 2 << 16,
	OC_FILE_I16  = 3 << 16,
	OC_FILE_U16  = 4 << 16,
	OC_FILE_I32  = 5 << 16,
	OC_FILE_U32  = 6 << 16,
	/* 8 bits allocated (256 max) */

	OC_INT8      = OC_VAR_I8   | OC_FILE_I8,
	OC_UINT8     = OC_VAR_U8   | OC_FILE_U8,
	OC_INT16     = OC_VAR_I16  | OC_FILE_I16,
	OC_UINT16    = OC_VAR_U16  | OC_FILE_U16,
	OC_INT32     = OC_VAR_I32  | OC_FILE_I32,
	OC_UINT32    = OC_VAR_U32  | OC_FILE_U32,

	OC_TILE      = OC_VAR_U32  | OC_FILE_U16,

	/**
	 * Dereference the pointer once before writing to it,
	 * so we do not have to use big static arrays.
	 */
	OC_DEREFERENCE_POINTER = 1 << 31,

	OC_END       = 0 ///< End of the whole chunk, all 32 bits set to zero
};

DECLARE_ENUM_AS_BIT_SET(OldChunkType)

typedef bool OldChunkProc(LoadgameState *ls, int num);

struct OldChunks {
	OldChunkType type;   ///< Type of field
	uint32 amount;       ///< Amount of fields

	void *ptr;           ///< Pointer where to save the data (may only be set if offset is 0)
	uint offset;         ///< Offset from basepointer (may only be set if ptr is NULL)
	OldChunkProc *proc;  ///< Pointer to function that is called with OC_CHUNK
};

/* If it fails, check lines above.. */
assert_compile(sizeof(TileIndex) == 4);

extern uint _bump_assert_value;
byte ReadByte(LoadgameState *ls);
bool LoadChunk(LoadgameState *ls, void *base, const OldChunks *chunks);

bool LoadTTDMain(LoadgameState *ls);
bool LoadTTOMain(LoadgameState *ls);

static inline uint16 ReadUint16(LoadgameState *ls)
{
	byte x = ReadByte(ls);
	return x | ReadByte(ls) << 8;
}

static inline uint32 ReadUint32(LoadgameState *ls)
{
	uint16 x = ReadUint16(ls);
	return x | ReadUint16(ls) << 16;
}

/* Help:
 *  - OCL_SVAR: load 'type' to offset 'offset' in a struct of type 'base', which must also
 *       be given via base in LoadChunk() as real pointer
 *  - OCL_VAR: load 'type' to a global var
 *  - OCL_END: every struct must end with this
 *  - OCL_NULL: read 'amount' of bytes and send them to /dev/null or something
 *  - OCL_CHUNK: load another proc to load a part of the savegame, 'amount' times
 *  - OCL_ASSERT: to check if we are really at the place we expect to be.. because old savegames are too binary to be sure ;)
 */
#define OCL_SVAR(type, base, offset)         { type,                 1,    NULL, (uint)cpp_offsetof(base, offset), NULL }
#define OCL_VAR(type, amount, pointer)       { type,            amount, pointer,    0,                             NULL }
#define OCL_END()                            { OC_END,               0,    NULL,    0,                             NULL }
#define OCL_CNULL(type, amount)              { OC_NULL | type,  amount,    NULL,    0,                             NULL }
#define OCL_CCHUNK(type, amount, proc)       { OC_CHUNK | type, amount,    NULL,    0,                             proc }
#define OCL_ASSERT(type, size)               { OC_ASSERT | type,     1,    NULL, size,                             NULL }
#define OCL_NULL(amount)        OCL_CNULL((OldChunkType)0, amount)
#define OCL_CHUNK(amount, proc) OCL_CCHUNK((OldChunkType)0, amount, proc)

#endif /* OLDLOADER_H */