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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.
*
*/
// The hash map (associative array) implementation in this file is
// based on the PyDict implementation of CPython. The erase() method
// is based on example code in the Wikipedia article on Hash tables.
#include "common/hashmap.h"
namespace Common {
// Hash function for strings, taken from CPython.
uint hashit(const char *p) {
uint hash = *p << 7;
byte c;
int size = 0;
while ((c = *p++)) {
hash = (1000003 * hash) ^ c;
size++;
}
return hash ^ size;
}
// Like hashit, but converts every char to lowercase before hashing.
uint hashit_lower(const char *p) {
uint hash = tolower(*p) << 7;
byte c;
int size = 0;
while ((c = *p++)) {
hash = (1000003 * hash) ^ tolower(c);
size++;
}
return hash ^ size;
}
#ifdef DEBUG_HASH_COLLISIONS
static double
g_collisions = 0,
g_dummyHits = 0,
g_lookups = 0,
g_collPerLook = 0,
g_capacity = 0,
g_size = 0;
static int g_max_capacity = 0, g_max_size = 0;
static int g_totalHashmaps = 0;
static int g_stats[4] = {0,0,0,0};
void updateHashCollisionStats(int collisions, int dummyHits, int lookups, int arrsize, int nele) {
g_collisions += collisions;
g_lookups += lookups;
g_dummyHits += dummyHits;
if (lookups)
g_collPerLook += (double)collisions / (double)lookups;
g_capacity += arrsize;
g_size += nele;
g_totalHashmaps++;
if (3*nele <= 2*8)
g_stats[0]++;
if (3*nele <= 2*16)
g_stats[1]++;
if (3*nele <= 2*32)
g_stats[2]++;
if (3*nele <= 2*64)
g_stats[3]++;
g_max_capacity = MAX(g_max_capacity, arrsize);
g_max_size = MAX(g_max_size, nele);
debug("%d hashmaps: colls %.1f; dummies hit %.1f, lookups %.1f; ratio %.3f%%; size %f (max: %d); capacity %f (max: %d)",
g_totalHashmaps,
g_collisions / g_totalHashmaps,
g_dummyHits / g_totalHashmaps,
g_lookups / g_totalHashmaps,
100 * g_collPerLook / g_totalHashmaps,
g_size / g_totalHashmaps, g_max_size,
g_capacity / g_totalHashmaps, g_max_capacity);
debug(" %d less than %d; %d less than %d; %d less than %d; %d less than %d",
g_stats[0], 2 * 8 / 3,
g_stats[1], 2 * 16 / 3,
g_stats[2], 2 * 32 / 3,
g_stats[3], 2 * 64 / 3);
// TODO:
// * Should record the maximal size of the map during its lifetime, not that at its death
// * Should do some statistics: how many maps are less than 2/3*8, 2/3*16, 2/3*32, ...
}
#endif
} // End of namespace Common
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