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110 lines
3.1 KiB
C++
110 lines
3.1 KiB
C++
/* ScummVM - Graphic Adventure Engine
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*
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* ScummVM is the legal property of its developers, whose names
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* are too numerous to list here. Please refer to the COPYRIGHT
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* file distributed with this source distribution.
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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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* 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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* 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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* $URL$
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* $Id$
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*
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*/
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// The hash map (associative array) implementation in this file is
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// based on the PyDict implementation of CPython. The erase() method
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// is based on example code in the Wikipedia article on Hash tables.
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#include "common/hashmap.h"
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namespace Common {
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// Hash function for strings, taken from CPython.
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uint hashit(const char *p) {
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uint hash = *p << 7;
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byte c;
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int size = 0;
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while ((c = *p++)) {
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hash = (1000003 * hash) ^ c;
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size++;
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}
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return hash ^ size;
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}
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// Like hashit, but converts every char to lowercase before hashing.
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uint hashit_lower(const char *p) {
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uint hash = tolower(*p) << 7;
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byte c;
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int size = 0;
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while ((c = *p++)) {
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hash = (1000003 * hash) ^ tolower(c);
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size++;
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}
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return hash ^ size;
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}
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#ifdef DEBUG_HASH_COLLISIONS
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static double
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g_collisions = 0,
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g_lookups = 0,
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g_collPerLook = 0,
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g_capacity = 0,
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g_size = 0;
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static int g_max_capacity = 0, g_max_size = 0;
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static int g_totalHashmaps = 0;
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static int g_stats[4] = {0,0,0,0};
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void updateHashCollisionStats(int collisions, int lookups, int arrsize, int nele) {
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g_collisions += collisions;
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g_lookups += lookups;
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if (lookups)
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g_collPerLook += (double)collisions / (double)lookups;
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g_capacity += arrsize;
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g_size += nele;
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g_totalHashmaps++;
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if (3*nele <= 2*8)
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g_stats[0]++;
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if (3*nele <= 2*16)
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g_stats[1]++;
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if (3*nele <= 2*32)
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g_stats[2]++;
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if (3*nele <= 2*64)
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g_stats[3]++;
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g_max_capacity = MAX(g_max_capacity, arrsize);
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g_max_size = MAX(g_max_size, nele);
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fprintf(stdout, "%d hashmaps: colls %.1f; lookups %.1f; ratio %.3f%%; size %f (max: %d); capacity %f (max: %d)\n",
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g_totalHashmaps,
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g_collisions / g_totalHashmaps,
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g_lookups / g_totalHashmaps,
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100 * g_collPerLook / g_totalHashmaps,
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g_size / g_totalHashmaps, g_max_size,
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g_capacity / g_totalHashmaps, g_max_capacity);
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fprintf(stdout, " %d less than %d; %d less than %d; %d less than %d; %d less than %d\n",
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g_stats[0], 2*8/3,
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g_stats[1],2*16/3,
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g_stats[2],2*32/3,
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g_stats[3],2*64/3);
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// TODO:
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// * Should record the maximal size of the map during its lifetime, not that at its death
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// * Should do some statistics: how many maps are less than 2/3*8, 2/3*16, 2/3*32, ...
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}
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#endif
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} // End of namespace Common
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