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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 SCI_ENGINE_SCRIPT_PATCHES_H
#define SCI_ENGINE_SCRIPT_PATCHES_H
#include "sci/sci.h"
namespace Sci {
// Please do not use the #defines, that are called SIG_CODE_* / PATCH_CODE_* inside signature/patch-tables
#define SIG_END 0xFFFF
#define SIG_MISMATCH 0xFFFE
#define SIG_COMMANDMASK 0xF000
#define SIG_VALUEMASK 0x0FFF
#define SIG_BYTEMASK 0x00FF
#define SIG_MAGICDWORD 0xF000
#define SIG_CODE_ADDTOOFFSET 0xE000
#define SIG_ADDTOOFFSET(_offset_) SIG_CODE_ADDTOOFFSET | (_offset_)
#define SIG_CODE_SELECTOR16 0x9000
#define SIG_SELECTOR16(_selectorID_) SIG_CODE_SELECTOR16 | SELECTOR_##_selectorID_
#define SIG_CODE_SELECTOR8 0x8000
#define SIG_SELECTOR8(_selectorID_) SIG_CODE_SELECTOR8 | SELECTOR_##_selectorID_
#define SIG_CODE_UINT16 0x1000
#define SIG_UINT16(_value_) SIG_CODE_UINT16 | ((_value_) & 0xFF), ((_value_) >> 8)
#define SIG_CODE_BYTE 0x0000
#define PATCH_END SIG_END
#define PATCH_COMMANDMASK SIG_COMMANDMASK
#define PATCH_VALUEMASK SIG_VALUEMASK
#define PATCH_BYTEMASK SIG_BYTEMASK
#define PATCH_CODE_ADDTOOFFSET SIG_CODE_ADDTOOFFSET
#define PATCH_ADDTOOFFSET(_offset_) SIG_CODE_ADDTOOFFSET | (_offset_)
#define PATCH_CODE_GETORIGINALBYTE 0xD000
#define PATCH_GETORIGINALBYTE(_offset_) PATCH_CODE_GETORIGINALBYTE | (_offset_)
#define PATCH_CODE_GETORIGINALBYTEADJUST 0xC000
#define PATCH_GETORIGINALBYTEADJUST(_offset_, _adjustValue_) PATCH_CODE_GETORIGINALBYTEADJUST | (_offset_), (uint16)(_adjustValue_)
#define PATCH_CODE_SELECTOR16 SIG_CODE_SELECTOR16
#define PATCH_SELECTOR16(_selectorID_) SIG_CODE_SELECTOR16 | SELECTOR_##_selectorID_
#define PATCH_CODE_SELECTOR8 SIG_CODE_SELECTOR8
#define PATCH_SELECTOR8(_selectorID_) SIG_CODE_SELECTOR8 | SELECTOR_##_selectorID_
#define PATCH_CODE_UINT16 SIG_CODE_UINT16
#define PATCH_UINT16(_value_) SIG_CODE_UINT16 | ((_value_) & 0xFF), ((_value_) >> 8)
#define PATCH_CODE_BYTE SIG_CODE_BYTE
// defines maximum scratch area for getting original bytes from unpatched script data
#define PATCH_VALUELIMIT 4096
struct SciScriptPatcherEntry {
bool defaultActive;
uint16 scriptNr;
const char *description;
int16 applyCount;
const uint16 *signatureData;
const uint16 *patchData;
};
#define SCI_SIGNATUREENTRY_TERMINATOR { false, 0, NULL, 0, NULL, NULL }
struct SciScriptPatcherRuntimeEntry {
bool active;
uint32 magicDWord;
int magicOffset;
};
/**
* ScriptPatcher class, handles on-the-fly patching of script data
*/
class ScriptPatcher {
public:
ScriptPatcher();
~ScriptPatcher();
// Calculates the magic DWord for fast search and verifies signature/patch data
// Returns the magic DWord in platform-specific byte-order. This is done on purpose for performance.
void calculateMagicDWordAndVerify(const char *signatureDescription, const uint16 *signatureData, bool magicDWordIncluded, uint32 &calculatedMagicDWord, int &calculatedMagicDWordOffset);
// Called when a script is loaded to check for signature matches and apply patches in such cases
void processScript(uint16 scriptNr, byte *scriptData, const uint32 scriptSize);
// Verifies, if a given signature matches the given script data (pointed to by additional byte offset)
bool verifySignature(uint32 byteOffset, const uint16 *signatureData, const char *signatureDescription, const byte *scriptData, const uint32 scriptSize);
// searches for a given signature inside script data
// returns -1 in case it was not found or an offset to the matching data
int32 findSignature(uint32 magicDWord, int magicOffset, const uint16 *signatureData, const char *patchDescription, const byte *scriptData, const uint32 scriptSize);
private:
// Initializes a patch table and creates run time information for it (for enabling/disabling), also calculates magic DWORD)
void initSignature(const SciScriptPatcherEntry *patchTable);
// Enables a patch inside the patch table (used for optional patches like CD+Text support for KQ6 & LB2)
void enablePatch(const SciScriptPatcherEntry *patchTable, const char *searchDescription);
// Searches for a given signature entry inside script data
// returns -1 in case it was not found or an offset to the matching data
int32 findSignature(const SciScriptPatcherEntry *patchEntry, const SciScriptPatcherRuntimeEntry *runtimeEntry, const byte *scriptData, const uint32 scriptSize);
// Applies a patch to a given script + offset (overwrites parts)
void applyPatch(const SciScriptPatcherEntry *patchEntry, byte *scriptData, const uint32 scriptSize, int32 signatureOffset);
Selector *_selectorIdTable;
SciScriptPatcherRuntimeEntry *_runtimeTable;
bool _isMacSci11;
};
} // End of namespace Sci
#endif // SCI_ENGINE_WORKAROUNDS_H
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