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84 lines
2.6 KiB
C++
84 lines
2.6 KiB
C++
/* ResidualVM - A 3D game interpreter
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*
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* ResidualVM is the legal property of its developers, whose names
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* are too numerous to list here. Please refer to the AUTHORS
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* file distributed with this source distribution.
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*
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* Additional copyright for this file:
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* Copyright (C) 1999-2000 Revolution Software Ltd.
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* This code is based on source code created by Revolution Software,
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* used with permission.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*
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*/
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#include "engines/icb/common/px_common.h"
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#include "common/system.h"
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namespace ICB {
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const char *hashTable = "ABCDEFGHIJKLMNOPQRSTUVWXYZ012345";
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uint32 EngineHashString(const char *fn) {
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if (fn == NULL)
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return 0;
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char *f;
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char c;
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uint32 n;
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n = 0;
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f = const_cast<char *>(fn);
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while ((c = *f) != 0) {
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n = (n << 7) + (n << 1) + n + c; // n=128n+2n+n+c -> n=131n+c
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// n=131*n+c; // n=131n+c
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f++;
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}
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return n;
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}
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// Take a filename, path whatever,
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// convert to hash value, then convert that hash value to
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// 7 character filename
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uint32 EngineHashFile(const char *fn, char *output) {
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uint32 hash = EngineHashString(fn);
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output[0] = hashTable[(hash >> 27) & 0x1F];
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output[1] = hashTable[(hash >> 22) & 0x1F];
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output[2] = hashTable[(hash >> 17) & 0x1F];
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output[3] = hashTable[(hash >> 12) & 0x1F];
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output[4] = hashTable[(hash >> 7) & 0x1F];
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output[5] = hashTable[(hash >> 2) & 0x1F];
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output[6] = hashTable[hash & 0x3];
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output[7] = '\0';
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return hash;
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}
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// Take a hash
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// convert that hash value to
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// 7 character filename
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uint32 EngineHashToFile(uint32 hash, char *output) {
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output[0] = hashTable[(hash >> 27) & 0x1F];
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output[1] = hashTable[(hash >> 22) & 0x1F];
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output[2] = hashTable[(hash >> 17) & 0x1F];
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output[3] = hashTable[(hash >> 12) & 0x1F];
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output[4] = hashTable[(hash >> 7) & 0x1F];
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output[5] = hashTable[(hash >> 2) & 0x1F];
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output[6] = hashTable[hash & 0x3];
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output[7] = '\0';
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return hash;
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}
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} // End of namespace ICB
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