scummvm/engines/icb/common/px_linkeddatafile.cpp
2022-07-30 15:14:30 +02:00

63 lines
2 KiB
C++

/* 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.
*
* 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 3 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, see <http://www.gnu.org/licenses/>.
*
*/
#include "engines/icb/common/px_rcutypes.h"
#include "engines/icb/common/px_string.h"
#include "engines/icb/common/px_common.h"
#include "engines/icb/common/px_clu_api.h"
#include "engines/icb/common/px_linkeddatafile.h"
namespace ICB {
// get NUMBER given HASH (does the search) - hashs must be ordered for this binary search to succeed.
uint32 LinkedDataObject::Fetch_item_number_by_hash(LinkedDataFile *file, const uint32 hash) {
int32 top, bottom;
int32 i;
uint32 current;
if (!FROM_LE_32(file->number_of_items))
return PX_LINKED_DATA_FILE_ERROR;
top = FROM_LE_32(file->number_of_items) - 1;
i = top >> 1;
bottom = 0;
for (;;) {
current = FROM_LE_32(file->list[i].name_hash_value);
if (hash == current)
return i;
else if (top == bottom)
return PX_LINKED_DATA_FILE_ERROR;
else if (hash > current) {
bottom = i + 1;
i = (top + bottom) >> 1;
} else {
top = i;
i = (top + bottom) >> 1;
}
}
}
} // End of namespace ICB