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/* 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.
*
*/
#ifndef KYRA_SCRIPT_H
#define KYRA_SCRIPT_H
#include "common/stream.h"
#include "common/array.h"
#include "common/func.h"
#include "common/iff_container.h"
namespace Kyra {
struct EMCState;
typedef Common::Functor1<EMCState *, int> Opcode;
struct EMCData {
char filename[13];
byte *text;
uint16 *data;
uint16 *ordr;
uint16 dataSize;
const Common::Array<const Opcode *> *sysFuncs;
};
struct EMCState {
enum {
kStackSize = 100,
kStackLastEntry = kStackSize - 1
};
const uint16 *ip;
const EMCData *dataPtr;
int16 retValue;
uint16 bp;
uint16 sp;
int16 regs[30]; // VM registers
int16 stack[kStackSize]; // VM stack
};
#define stackPos(x) (script->stack[script->sp+x])
#define stackPosString(x) ((const char *)&script->dataPtr->text[READ_BE_UINT16(&script->dataPtr->text[stackPos(x)<<1])])
class Resource;
class KyraEngine_v1;
class IFFParser : public Common::IFFParser {
public:
IFFParser(Common::ReadStream &input) : Common::IFFParser(&input) {
// It seems Westwood missunderstood the 'size' field of the FORM chunk.
//
// For EMC scripts (type EMC2) it's filesize instead of filesize - 8,
// means accidently including the 8 bytes used by the chunk header for the FORM
// chunk.
//
// For TIM scripts (type AVFS) it's filesize - 12 instead of filesize - 8,
// means it will not include the size of the 'type' field in the FORM chunk,
// instead of only not including the chunk header size.
//
// Both lead to some problems in our IFF parser, either reading after the end
// of file or producing a "Chunk overread" error message. To work around this
// we need to adjust the size field properly.
// Fix for certain Russian fan translations:
// Westwood's original code completely ignores the FORM chunk and its size
// setting. After opening a TIM or EMC file they just check whether the FORM
// chunk exists (as a kind of file type verification) and then immediately seek
// behind the FORM chunk.
// This means that their parser is immune to weird fan translation scripts
// where the file size doesn't match the form chunk size. In our implemetation
// this would produce "Chunk overread" errors.
// Westwood also always pads all chunk sizes to 2 byte alignment after reading
// them from the file (not with FORM though, since they completely ignore it).
// This seems to do the trick for our FORM chunk size issue with the Russian
// fan translations. Another method which I have tried and which seems to work
// well would be simply setting _formChunk.size to the file size (-12 for TIM).
_formChunk.size = (_formChunk.size + 1) & ~1;
if (_formType == MKTAG('E','M','C','2'))
_formChunk.size -= 8;
else if (_formType == MKTAG('A','V','F','S'))
_formChunk.size += 4;
}
};
class EMCInterpreter {
public:
EMCInterpreter(KyraEngine_v1 *vm);
bool load(const char *filename, EMCData *data, const Common::Array<const Opcode *> *opcodes);
void unload(EMCData *data);
void init(EMCState *scriptState, const EMCData *data);
bool start(EMCState *script, int function);
bool isValid(EMCState *script);
bool run(EMCState *script);
protected:
KyraEngine_v1 *_vm;
int16 _parameter;
const char *_filename;
EMCData *_scriptData;
bool callback(Common::IFFChunk &chunk);
typedef void (EMCInterpreter::*OpcodeProc)(EMCState *);
struct OpcodeEntry {
OpcodeProc proc;
const char *desc;
};
const OpcodeEntry *_opcodes;
private:
void op_jmp(EMCState *);
void op_setRetValue(EMCState *);
void op_pushRetOrPos(EMCState *);
void op_push(EMCState *);
void op_pushReg(EMCState *);
void op_pushBPNeg(EMCState *);
void op_pushBPAdd(EMCState *);
void op_popRetOrPos(EMCState *);
void op_popReg(EMCState *);
void op_popBPNeg(EMCState *);
void op_popBPAdd(EMCState *);
void op_addSP(EMCState *);
void op_subSP(EMCState *);
void op_sysCall(EMCState *);
void op_ifNotJmp(EMCState *);
void op_negate(EMCState *);
void op_eval(EMCState *);
void op_setRetAndJmp(EMCState *);
};
} // End of namespace Kyra
#endif
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