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scummvm/engines/icb/common/ptr_util.cpp
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/* ResidualVM - A 3D game interpreter
*
* ResidualVM is the legal property of its developers, whose names
* are too numerous to list here. Please refer to the AUTHORS
* file distributed with this source distribution.
*
* Additional copyright for this file:
* Copyright (C) 1999-2000 Revolution Software Ltd.
* This code is based on source code created by Revolution Software,
* used with permission.
*
* 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.
*
*/
#include "engines/icb/common/px_common.h"
#include "common/array.h"
namespace ICB {
namespace MemoryUtil {
const int PTR_ARRAY_MAX(1024);
// map pointers to 32-bit references (bottom 32-bits of address)
struct PointerReference {
uint32 ref;
uint8 *ptr;
};
Common::Array<PointerReference> ptrArray;
uint32 encodePtr(uint8 *ptr) {
PointerReference ptrRef;
ptrdiff_t diff = ptr - (uint8 *)0;
ptrRef.ref = (uint32)(diff & 0xFFFFFFFF);
ptrRef.ptr = ptr;
// find free slot
for (Common::Array<PointerReference>::iterator it = ptrArray.begin(); it < ptrArray.end(); it++) {
if (it->ref == 0) {
*it = ptrRef; // store
return ptrRef.ref;
}
}
// append
ptrArray.push_back(ptrRef);
if (ptrArray.size() >= (uint)PTR_ARRAY_MAX) {
error("MemoryUtil::encodePtr(): too many pointers (MAX = %u)\n", PTR_ARRAY_MAX);
}
return ptrRef.ref;
}
uint8 *resolvePtr(uint32 ref) {
if (ref == 0)
return NULL;
// do a linear search
for (Common::Array<PointerReference>::iterator it = ptrArray.begin(); it < ptrArray.end(); it++) {
if (it->ref == ref) {
uint8 *ptr = it->ptr;
// purge
it->ref = 0;
it->ptr = 0;
return ptr;
}
}
error("MemoryUtil::resolvePtr(%08x) COULD NOT RESOLVE POINTER!\n", ref);
return NULL;
}
void clearAllPtrs(void) { ptrArray.clear(); }
}
} // End of namespace ICB