edgehash.c

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/*
 * $Id: edgehash.c 36826 2011-05-23 08:14:29Z campbellbarton $
 *
 * ***** BEGIN GPL LICENSE BLOCK *****
 *
 * 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 Original Code is Copyright (C) 2001-2002 by NaN Holding BV.
 * All rights reserved.
 *
 * The Original Code is: none of this file.
 *
 * Contributor(s): Daniel Dunbar
 *
 * ***** END GPL LICENSE BLOCK *****
 * A general (pointer -> pointer) hash table ADT
 */

#include <stdlib.h>
#include <string.h>

#include "MEM_guardedalloc.h"
#include "BLI_edgehash.h"

/***/

static unsigned int hashsizes[]= {
        1, 3, 5, 11, 17, 37, 67, 131, 257, 521, 1031, 2053, 4099, 8209, 
        16411, 32771, 65537, 131101, 262147, 524309, 1048583, 2097169, 
        4194319, 8388617, 16777259, 33554467, 67108879, 134217757, 
        268435459
};

#define EDGEHASH(v0,v1)         ((v0*39)^(v1*31))

/***/

typedef struct Entry Entry;
struct Entry {
        Entry *next;
        int v0, v1;
        void *val;
};

struct EdgeHash {
        Entry **buckets;
        int nbuckets, nentries, cursize;
};

/***/

EdgeHash *BLI_edgehash_new(void) {
        EdgeHash *eh= MEM_mallocN(sizeof(*eh), "EdgeHash");
        eh->cursize= 0;
        eh->nentries= 0;
        eh->nbuckets= hashsizes[eh->cursize];
        
        eh->buckets= malloc(eh->nbuckets*sizeof(*eh->buckets));
        memset(eh->buckets, 0, eh->nbuckets*sizeof(*eh->buckets));
        
        return eh;
}

void BLI_edgehash_insert(EdgeHash *eh, int v0, int v1, void *val) {
        unsigned int hash;
        Entry *e= malloc(sizeof(*e));

        if (v1<v0) {
                v0 ^= v1;
                v1 ^= v0;
                v0 ^= v1;
        }
         hash = EDGEHASH(v0,v1)%eh->nbuckets;

        e->v0 = v0;
        e->v1 = v1;
        e->val = val;
        e->next= eh->buckets[hash];
        eh->buckets[hash]= e;
        
        if (++eh->nentries>eh->nbuckets*3) {
                Entry **old= eh->buckets;
                int i, nold= eh->nbuckets;
                
                eh->nbuckets= hashsizes[++eh->cursize];
                eh->buckets= malloc(eh->nbuckets*sizeof(*eh->buckets));
                memset(eh->buckets, 0, eh->nbuckets*sizeof(*eh->buckets));
                
                for (i=0; i<nold; i++) {
                        for (e= old[i]; e;) {
                                Entry *n= e->next;
                                
                                hash= EDGEHASH(e->v0,e->v1)%eh->nbuckets;
                                e->next= eh->buckets[hash];
                                eh->buckets[hash]= e;
                                
                                e= n;
                        }
                }
                
                free(old);
        }
}

void** BLI_edgehash_lookup_p(EdgeHash *eh, int v0, int v1) {
        unsigned int hash;
        Entry *e;

        if (v1<v0) {
                v0 ^= v1;
                v1 ^= v0;
                v0 ^= v1;
        }
        hash = EDGEHASH(v0,v1)%eh->nbuckets;
        for (e= eh->buckets[hash]; e; e= e->next)
                if (v0==e->v0 && v1==e->v1)
                        return &e->val;
        
        return NULL;
}

void* BLI_edgehash_lookup(EdgeHash *eh, int v0, int v1) {
        void **value_p = BLI_edgehash_lookup_p(eh,v0,v1);

        return value_p?*value_p:NULL;
}

int BLI_edgehash_haskey(EdgeHash *eh, int v0, int v1) {
        return BLI_edgehash_lookup_p(eh, v0, v1)!=NULL;
}

int BLI_edgehash_size(EdgeHash *eh) {
        return eh->nentries;
}

void BLI_edgehash_clear(EdgeHash *eh, EdgeHashFreeFP valfreefp) {
        int i;
        
        for (i=0; i<eh->nbuckets; i++) {
                Entry *e;
                
                for (e= eh->buckets[i]; e; ) {
                        Entry *n= e->next;
                        
                        if (valfreefp) valfreefp(e->val);
                        free(e);
                        
                        e= n;
                }
                eh->buckets[i]= NULL;
        }

        eh->nentries= 0;
}

void BLI_edgehash_free(EdgeHash *eh, EdgeHashFreeFP valfreefp) {
        BLI_edgehash_clear(eh, valfreefp);
        
        free(eh->buckets);
        MEM_freeN(eh);
}


/***/

struct EdgeHashIterator {
        EdgeHash *eh;
        int curBucket;
        Entry *curEntry;
};

EdgeHashIterator *BLI_edgehashIterator_new(EdgeHash *eh) {
        EdgeHashIterator *ehi= malloc(sizeof(*ehi));
        ehi->eh= eh;
        ehi->curEntry= NULL;
        ehi->curBucket= -1;
        while (!ehi->curEntry) {
                ehi->curBucket++;
                if (ehi->curBucket==ehi->eh->nbuckets)
                        break;
                ehi->curEntry= ehi->eh->buckets[ehi->curBucket];
        }
        return ehi;
}
void BLI_edgehashIterator_free(EdgeHashIterator *ehi) {
        free(ehi);
}

void BLI_edgehashIterator_getKey(EdgeHashIterator *ehi, int *v0_r, int *v1_r) {
        if (ehi->curEntry) {
                *v0_r = ehi->curEntry->v0;
                *v1_r = ehi->curEntry->v1;
        }
}
void *BLI_edgehashIterator_getValue(EdgeHashIterator *ehi) {
        return ehi->curEntry?ehi->curEntry->val:NULL;
}

void BLI_edgehashIterator_setValue(EdgeHashIterator *ehi, void *val) {
        if(ehi->curEntry)
                ehi->curEntry->val= val;
}

void BLI_edgehashIterator_step(EdgeHashIterator *ehi) {
        if (ehi->curEntry) {
                ehi->curEntry= ehi->curEntry->next;
                while (!ehi->curEntry) {
                        ehi->curBucket++;
                        if (ehi->curBucket==ehi->eh->nbuckets)
                                break;
                        ehi->curEntry= ehi->eh->buckets[ehi->curBucket];
                }
        }
}
int BLI_edgehashIterator_isDone(EdgeHashIterator *ehi) {
        return !ehi->curEntry;
}