[thirdparty/squid.git] / lib / hash.c


/*
 * $Id: hash.c,v 1.12 2001/03/07 17:57:37 wessels Exp $
 *
 * DEBUG: section 0     Hash Tables
 * AUTHOR: Harvest Derived
 *
 * SQUID Web Proxy Cache          http://www.squid-cache.org/
 * ----------------------------------------------------------
 *
 *  Squid is the result of efforts by numerous individuals from
 *  the Internet community; see the CONTRIBUTORS file for full
 *  details.   Many organizations have provided support for Squid's
 *  development; see the SPONSORS file for full details.  Squid is
 *  Copyrighted (C) 2001 by the Regents of the University of
 *  California; see the COPYRIGHT file for full details.  Squid
 *  incorporates software developed and/or copyrighted by other
 *  sources; see the CREDITS file for full details.
 *
 *  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., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
 *
 */

#include "config.h"

#if HAVE_STDIO_H
#include <stdio.h>
#endif
#if HAVE_STDLIB_H
#include <stdlib.h>
#endif
#if HAVE_STRING_H
#include <string.h>
#endif
#if HAVE_UNISTD_H
#include <unistd.h>
#endif
#if HAVE_GNUMALLLOC_H
#include <gnumalloc.h>
#elif HAVE_MALLOC_H && !defined(_SQUID_FREEBSD_) && !defined(_SQUID_NEXT_)
#include <malloc.h>
#endif
#if HAVE_ASSERT_H
#include <assert.h>
#endif
#if HAVE_MATH_H
#include <math.h>
#endif

#include "hash.h"
#include "util.h"

static void hash_next_bucket(hash_table * hid);

unsigned int
hash_string(const void *data, unsigned int size)
{
    const char *s = data;
    unsigned int n = 0;
    unsigned int j = 0;
    unsigned int i = 0;
    while (*s) {
	j++;
	n ^= 271 * (unsigned) *s++;
    }
    i = n ^ (j * 271);
    return i % size;
}

/* the following function(s) were adapted from
 *    usr/src/lib/libc/db/hash_func.c, 4.4 BSD lite */

/* Hash function from Chris Torek. */
unsigned int
hash4(const void *data, unsigned int size)
{
    const char *key = data;
    size_t loop;
    unsigned int h;
    size_t len;

#define HASH4a   h = (h << 5) - h + *key++;
#define HASH4b   h = (h << 5) + h + *key++;
#define HASH4 HASH4b

    h = 0;
    len = strlen(key);
    loop = len >> 3;
    switch (len & (8 - 1)) {
    case 0:
	break;
    case 7:
	HASH4;
	/* FALLTHROUGH */
    case 6:
	HASH4;
	/* FALLTHROUGH */
    case 5:
	HASH4;
	/* FALLTHROUGH */
    case 4:
	HASH4;
	/* FALLTHROUGH */
    case 3:
	HASH4;
	/* FALLTHROUGH */
    case 2:
	HASH4;
	/* FALLTHROUGH */
    case 1:
	HASH4;
    }
    while (loop--) {
	HASH4;
	HASH4;
	HASH4;
	HASH4;
	HASH4;
	HASH4;
	HASH4;
	HASH4;
    }
    return h % size;
}

/*
 *  hash_create - creates a new hash table, uses the cmp_func
 *  to compare keys.  Returns the identification for the hash table;
 *  otherwise returns a negative number on error.
 */
hash_table *
hash_create(HASHCMP * cmp_func, int hash_sz, HASHHASH * hash_func)
{
    hash_table *hid = xcalloc(1, sizeof(hash_table));
    if (!hash_sz)
	hid->size = (unsigned int) DEFAULT_HASH_SIZE;
    else
	hid->size = (unsigned int) hash_sz;
    /* allocate and null the buckets */
    hid->buckets = xcalloc(hid->size, sizeof(hash_link *));
    hid->cmp = cmp_func;
    hid->hash = hash_func;
    hid->next = NULL;
    hid->current_slot = 0;
    return hid;
}

/*
 *  hash_join - joins a hash_link under its key lnk->key
 *  into the hash table 'hid'.  
 *
 *  It does not copy any data into the hash table, only links pointers.
 */
void
hash_join(hash_table * hid, hash_link * lnk)
{
    int i;
    i = hid->hash(lnk->key, hid->size);
    lnk->next = hid->buckets[i];
    hid->buckets[i] = lnk;
    hid->count++;
}

/*
 *  hash_lookup - locates the item under the key 'k' in the hash table
 *  'hid'.  Returns a pointer to the hash bucket on success; otherwise
 *  returns NULL.
 */
void *
hash_lookup(hash_table * hid, const void *k)
{
    hash_link *walker;
    int b;
    assert(k != NULL);
    b = hid->hash(k, hid->size);
    for (walker = hid->buckets[b]; walker != NULL; walker = walker->next) {
	if ((hid->cmp) (k, walker->key) == 0)
	    return (walker);
	assert(walker != walker->next);
    }
    return NULL;
}

static void
hash_next_bucket(hash_table * hid)
{
    while (hid->next == NULL && ++hid->current_slot < hid->size)
	hid->next = hid->buckets[hid->current_slot];
}

/*
 *  hash_first - initializes the hash table for the hash_next()
 *  function.
 */
void
hash_first(hash_table * hid)
{
    assert(NULL == hid->next);
    hid->current_slot = 0;
    hid->next = hid->buckets[hid->current_slot];
    if (NULL == hid->next)
	hash_next_bucket(hid);
}

/*
 *  hash_next - returns the next item in the hash table 'hid'.
 *  Otherwise, returns NULL on error or end of list.  
 *
 *  MUST call hash_first() before hash_next().
 */
void *
hash_next(hash_table * hid)
{
    hash_link *this = hid->next;
    if (NULL == this)
	return NULL;
    hid->next = this->next;
    if (NULL == hid->next)
	hash_next_bucket(hid);
    return this;
}

/*
 *  hash_last - resets hash traversal state to NULL
 *
 */
void
hash_last(hash_table * hid)
{
    assert(hid);
    hid->next = NULL;
    hid->current_slot = 0;
}

/*
 *  hash_remove_link - deletes the given hash_link node from the 
 *  hash table 'hid'.  Does not free the item, only removes it
 *  from the list.
 *
 *  An assertion is triggered if the hash_link is not found in the
 *  list.
 */
void
hash_remove_link(hash_table * hid, hash_link * hl)
{
    hash_link **P;
    int i;
    assert(hl != NULL);
    i = hid->hash(hl->key, hid->size);
    for (P = &hid->buckets[i]; *P; P = &(*P)->next) {
	if (*P != hl)
	    continue;
	*P = hl->next;
	if (hid->next == hl) {
	    hid->next = hl->next;
	    if (NULL == hid->next)
		hash_next_bucket(hid);
	}
	hid->count--;
	return;
    }
    assert(0);
}

/*
 *  hash_get_bucket - returns the head item of the bucket 
 *  in the hash table 'hid'. Otherwise, returns NULL on error.
 */
hash_link *
hash_get_bucket(hash_table * hid, unsigned int bucket)
{
    if (bucket >= hid->size)
	return NULL;
    return (hid->buckets[bucket]);
}

void
hashFreeItems(hash_table * hid, HASHFREE * free_func)
{
    hash_link *l;
    hash_link **list;
    int i = 0;
    int j;
    list = xcalloc(hid->count, sizeof(hash_link *));
    hash_first(hid);
    while ((l = hash_next(hid)) && i < hid->count) {
	*(list + i) = l;
	i++;
    }
    for (j = 0; j < i; j++)
	free_func(*(list + j));
    xfree(list);
}

void
hashFreeMemory(hash_table * hid)
{
    assert(hid);
    if (hid->buckets)
	xfree(hid->buckets);
    xfree(hid);
}

static int hash_primes[] =
{
    103,
    229,
    467,
    977,
    1979,
    4019,
    6037,
    7951,
    12149,
    16231,
    33493,
    65357
};

int
hashPrime(int n)
{
    int I = sizeof(hash_primes) / sizeof(int);
    int i;
    int best_prime = hash_primes[0];
    double min = fabs(log((double) n) - log((double) hash_primes[0]));
    double d;
    for (i = 0; i < I; i++) {
	d = fabs(log((double) n) - log((double) hash_primes[i]));
	if (d > min)
	    continue;
	min = d;
	best_prime = hash_primes[i];
    }
    return best_prime;
}

/*
 * return the key of a hash_link as a const string
 */
const char *
hashKeyStr(hash_link * hl)
{
    return (const char *) hl->key;
}


#ifdef USE_HASH_DRIVER
/*
 *  hash-driver - Run with a big file as stdin to insert each line into the
 *  hash table, then prints the whole hash table, then deletes a random item,
 *  and prints the table again...
 */
int
main(void)
{
    hash_table *hid;
    int i;
    LOCAL_ARRAY(char, buf, BUFSIZ);
    LOCAL_ARRAY(char, todelete, BUFSIZ);
    hash_link *walker = NULL;

    todelete[0] = '\0';
    printf("init\n");

    printf("creating hash table\n");
    if ((hid = hash_create((HASHCMP *) strcmp, 229, hash4)) < 0) {
	printf("hash_create error.\n");
	exit(1);
    }
    printf("done creating hash table: %d\n", hid);

    while (fgets(buf, BUFSIZ, stdin)) {
	buf[strlen(buf) - 1] = '\0';
	printf("Inserting '%s' for item %p to hash table: %d\n",
	    buf, buf, hid);
	hash_insert(hid, xstrdup(buf), (void *) 0x12345678);
	if (random() % 17 == 0)
	    strcpy(todelete, buf);
    }

    printf("walking hash table...\n");
    for (i = 0, walker = hash_first(hid); walker; walker = hash_next(hid)) {
	printf("item %5d: key: '%s' item: %p\n", i++, walker->key,
	    walker->item);
    }
    printf("done walking hash table...\n");

    if (todelete[0]) {
	printf("deleting %s from %d\n", todelete, hid);
	if (hash_delete(hid, todelete))
	    printf("hash_delete error\n");
    }
    printf("walking hash table...\n");
    for (i = 0, walker = hash_first(hid); walker; walker = hash_next(hid)) {
	printf("item %5d: key: '%s' item: %p\n", i++, walker->key,
	    walker->item);
    }
    printf("done walking hash table...\n");


    printf("driver finished.\n");
    exit(0);
}
#endif
Commit	Line	Data
f52a7d75	1
f52a7d75	2	/*
4fba1a24	3	* $Id: hash.c,v 1.12 2001/03/07 17:57:37 wessels Exp $
f52a7d75	4	*
	5	* DEBUG: section 0 Hash Tables
	6	* AUTHOR: Harvest Derived
	7	*
2b6662ba	8	* SQUID Web Proxy Cache http://www.squid-cache.org/
f52a7d75	9	* ----------------------------------------------------------
f52a7d75	10	*
2b6662ba	11	* Squid is the result of efforts by numerous individuals from
	12	* the Internet community; see the CONTRIBUTORS file for full
	13	* details. Many organizations have provided support for Squid's
	14	* development; see the SPONSORS file for full details. Squid is
	15	* Copyrighted (C) 2001 by the Regents of the University of
	16	* California; see the COPYRIGHT file for full details. Squid
	17	* incorporates software developed and/or copyrighted by other
	18	* sources; see the CREDITS file for full details.
f52a7d75	19	*
	20	* This program is free software; you can redistribute it and/or modify
	21	* it under the terms of the GNU General Public License as published by
	22	* the Free Software Foundation; either version 2 of the License, or
	23	* (at your option) any later version.
	24	*
	25	* This program is distributed in the hope that it will be useful,
	26	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	27	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	28	* GNU General Public License for more details.
	29	*
	30	* You should have received a copy of the GNU General Public License
	31	* along with this program; if not, write to the Free Software
	32	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
	33	*
	34	*/
	35
	36	#include "config.h"
	37
	38	#if HAVE_STDIO_H
	39	#include <stdio.h>
	40	#endif
	41	#if HAVE_STDLIB_H
	42	#include <stdlib.h>
	43	#endif
	44	#if HAVE_STRING_H
	45	#include <string.h>
	46	#endif
	47	#if HAVE_UNISTD_H
	48	#include <unistd.h>
	49	#endif
	50	#if HAVE_GNUMALLLOC_H
	51	#include <gnumalloc.h>
	52	#elif HAVE_MALLOC_H && !defined(_SQUID_FREEBSD_) && !defined(_SQUID_NEXT_)
	53	#include <malloc.h>
	54	#endif
	55	#if HAVE_ASSERT_H
	56	#include <assert.h>
	57	#endif
e880cefa	58	#if HAVE_MATH_H
	59	#include <math.h>
	60	#endif
f52a7d75	61
	62	#include "hash.h"
	63	#include "util.h"
	64
	65	static void hash_next_bucket(hash_table * hid);
	66
	67	unsigned int
	68	hash_string(const void *data, unsigned int size)
	69	{
	70	const char *s = data;
	71	unsigned int n = 0;
	72	unsigned int j = 0;
	73	unsigned int i = 0;
	74	while (*s) {
	75	j++;
	76	n ^= 271 * (unsigned) *s++;
	77	}
	78	i = n ^ (j * 271);
	79	return i % size;
	80	}
	81
	82	/* the following function(s) were adapted from
	83	* usr/src/lib/libc/db/hash_func.c, 4.4 BSD lite */
	84
	85	/* Hash function from Chris Torek. */
	86	unsigned int
	87	hash4(const void *data, unsigned int size)
	88	{
	89	const char *key = data;
	90	size_t loop;
	91	unsigned int h;
	92	size_t len;
	93
	94	#define HASH4a h = (h << 5) - h + *key++;
	95	#define HASH4b h = (h << 5) + h + *key++;
	96	#define HASH4 HASH4b
	97
	98	h = 0;
	99	len = strlen(key);
	100	loop = len >> 3;
	101	switch (len & (8 - 1)) {
	102	case 0:
	103	break;
	104	case 7:
	105	HASH4;
	106	/* FALLTHROUGH */
	107	case 6:
	108	HASH4;
	109	/* FALLTHROUGH */
	110	case 5:
	111	HASH4;
	112	/* FALLTHROUGH */
	113	case 4:
	114	HASH4;
	115	/* FALLTHROUGH */
	116	case 3:
	117	HASH4;
	118	/* FALLTHROUGH */
	119	case 2:
	120	HASH4;
	121	/* FALLTHROUGH */
	122	case 1:
	123	HASH4;
	124	}
125	while (loop--) {
126	HASH4;
127	HASH4;
128	HASH4;
129	HASH4;
130	HASH4;
131	HASH4;
132	HASH4;
133	HASH4;
134	}
135	return h % size;
136	}
137
138	/*
139	* hash_create - creates a new hash table, uses the cmp_func
140	* to compare keys. Returns the identification for the hash table;
141	* otherwise returns a negative number on error.
142	*/
143	hash_table *
144	hash_create(HASHCMP * cmp_func, int hash_sz, HASHHASH * hash_func)
145	{
146	hash_table *hid = xcalloc(1, sizeof(hash_table));
147	if (!hash_sz)
148	hid->size = (unsigned int) DEFAULT_HASH_SIZE;
149	else
150	hid->size = (unsigned int) hash_sz;
151	/* allocate and null the buckets */
152	hid->buckets = xcalloc(hid->size, sizeof(hash_link *));
153	hid->cmp = cmp_func;
154	hid->hash = hash_func;
155	hid->next = NULL;
156	hid->current_slot = 0;
157	return hid;
158	}
159
160	/*
161	* hash_join - joins a hash_link under its key lnk->key
162	* into the hash table 'hid'.
163	*
164	* It does not copy any data into the hash table, only links pointers.
165	*/
166	void
167	hash_join(hash_table * hid, hash_link * lnk)
168	{
169	int i;
170	i = hid->hash(lnk->key, hid->size);
171	lnk->next = hid->buckets[i];
172	hid->buckets[i] = lnk;
173	hid->count++;
174	}
175
176	/*
177	* hash_lookup - locates the item under the key 'k' in the hash table
178	* 'hid'. Returns a pointer to the hash bucket on success; otherwise
179	* returns NULL.
180	*/
181	void *
182	hash_lookup(hash_table * hid, const void *k)
183	{
184	hash_link *walker;
185	int b;
186	assert(k != NULL);
187	b = hid->hash(k, hid->size);
188	for (walker = hid->buckets[b]; walker != NULL; walker = walker->next) {
189	if ((hid->cmp) (k, walker->key) == 0)
190	return (walker);
191	assert(walker != walker->next);
192	}
193	return NULL;
194	}
195
196	static void
197	hash_next_bucket(hash_table * hid)
198	{
199	while (hid->next == NULL && ++hid->current_slot < hid->size)
200	hid->next = hid->buckets[hid->current_slot];
201	}
202
203	/*
204	* hash_first - initializes the hash table for the hash_next()
205	* function.
206	*/
207	void
208	hash_first(hash_table * hid)
209	{
210	assert(NULL == hid->next);
211	hid->current_slot = 0;
212	hid->next = hid->buckets[hid->current_slot];
213	if (NULL == hid->next)
214	hash_next_bucket(hid);
215	}
216
217	/*
218	* hash_next - returns the next item in the hash table 'hid'.
219	* Otherwise, returns NULL on error or end of list.
220	*
221	* MUST call hash_first() before hash_next().
222	*/
223	void *
224	hash_next(hash_table * hid)
225	{
226	hash_link *this = hid->next;
227	if (NULL == this)
228	return NULL;
229	hid->next = this->next;
230	if (NULL == hid->next)
231	hash_next_bucket(hid);
232	return this;
233	}
234
2c4f7ab2	235	/*
	236	* hash_last - resets hash traversal state to NULL
	237	*
	238	*/
	239	void
ab96e65c	240	hash_last(hash_table * hid)
2c4f7ab2	241	{
	242	assert(hid);
	243	hid->next = NULL;
	244	hid->current_slot = 0;
	245	}
	246
f52a7d75	247	/*
	248	* hash_remove_link - deletes the given hash_link node from the
	249	* hash table 'hid'. Does not free the item, only removes it
	250	* from the list.
	251	*
4fba1a24	252	* An assertion is triggered if the hash_link is not found in the
4fba1a24	253	* list.
f52a7d75	254	*/
	255	void
	256	hash_remove_link(hash_table * hid, hash_link * hl)
	257	{
	258	hash_link **P;
	259	int i;
	260	assert(hl != NULL);
	261	i = hid->hash(hl->key, hid->size);
	262	for (P = &hid->buckets[i]; P; P = &(P)->next) {
	263	if (*P != hl)
	264	continue;
	265	*P = hl->next;
	266	if (hid->next == hl) {
	267	hid->next = hl->next;
	268	if (NULL == hid->next)
	269	hash_next_bucket(hid);
	270	}
	271	hid->count--;
	272	return;
	273	}
e530de6c	274	assert(0);
f52a7d75	275	}
	276
	277	/*
	278	* hash_get_bucket - returns the head item of the bucket
	279	* in the hash table 'hid'. Otherwise, returns NULL on error.
	280	*/
	281	hash_link *
	282	hash_get_bucket(hash_table * hid, unsigned int bucket)
	283	{
	284	if (bucket >= hid->size)
	285	return NULL;
	286	return (hid->buckets[bucket]);
	287	}
	288
	289	void
	290	hashFreeItems(hash_table * hid, HASHFREE * free_func)
	291	{
	292	hash_link *l;
	293	hash_link **list;
	294	int i = 0;
	295	int j;
	296	list = xcalloc(hid->count, sizeof(hash_link *));
	297	hash_first(hid);
	298	while ((l = hash_next(hid)) && i < hid->count) {
	299	*(list + i) = l;
	300	i++;
	301	}
	302	for (j = 0; j < i; j++)
	303	free_func(*(list + j));
	304	xfree(list);
	305	}
	306
	307	void
	308	hashFreeMemory(hash_table * hid)
	309	{
	310	assert(hid);
efacbef0	311	if (hid->buckets)
461eef68	312	xfree(hid->buckets);
f52a7d75	313	xfree(hid);
	314	}
	315
	316	static int hash_primes[] =
	317	{
	318	103,
	319	229,
	320	467,
	321	977,
	322	1979,
	323	4019,
	324	6037,
	325	7951,
	326	12149,
	327	16231,
	328	33493,
	329	65357
	330	};
	331
	332	int
	333	hashPrime(int n)
	334	{
	335	int I = sizeof(hash_primes) / sizeof(int);
	336	int i;
	337	int best_prime = hash_primes[0];
d87ebd78	338	double min = fabs(log((double) n) - log((double) hash_primes[0]));
f52a7d75	339	double d;
f52a7d75	340	for (i = 0; i < I; i++) {
d87ebd78	341	d = fabs(log((double) n) - log((double) hash_primes[i]));
f52a7d75	342	if (d > min)
	343	continue;
	344	min = d;
	345	best_prime = hash_primes[i];
	346	}
	347	return best_prime;
	348	}
	349
186477c1	350	/*
	351	* return the key of a hash_link as a const string
	352	*/
	353	const char *
	354	hashKeyStr(hash_link * hl)
	355	{
	356	return (const char *) hl->key;
	357	}
	358
f52a7d75	359
	360	#ifdef USE_HASH_DRIVER
	361	/*
	362	* hash-driver - Run with a big file as stdin to insert each line into the
	363	* hash table, then prints the whole hash table, then deletes a random item,
	364	* and prints the table again...
	365	*/
	366	int
	367	main(void)
	368	{
	369	hash_table *hid;
	370	int i;
	371	LOCAL_ARRAY(char, buf, BUFSIZ);
	372	LOCAL_ARRAY(char, todelete, BUFSIZ);
	373	hash_link *walker = NULL;
	374
	375	todelete[0] = '\0';
	376	printf("init\n");
	377
	378	printf("creating hash table\n");
	379	if ((hid = hash_create((HASHCMP *) strcmp, 229, hash4)) < 0) {
	380	printf("hash_create error.\n");
	381	exit(1);
	382	}
	383	printf("done creating hash table: %d\n", hid);
	384
	385	while (fgets(buf, BUFSIZ, stdin)) {
	386	buf[strlen(buf) - 1] = '\0';
	387	printf("Inserting '%s' for item %p to hash table: %d\n",
	388	buf, buf, hid);
	389	hash_insert(hid, xstrdup(buf), (void *) 0x12345678);
	390	if (random() % 17 == 0)
	391	strcpy(todelete, buf);
	392	}
	393
	394	printf("walking hash table...\n");
	395	for (i = 0, walker = hash_first(hid); walker; walker = hash_next(hid)) {
	396	printf("item %5d: key: '%s' item: %p\n", i++, walker->key,
	397	walker->item);
	398	}
	399	printf("done walking hash table...\n");
	400
	401	if (todelete[0]) {
	402	printf("deleting %s from %d\n", todelete, hid);
	403	if (hash_delete(hid, todelete))
	404	printf("hash_delete error\n");
	405	}
	406	printf("walking hash table...\n");
	407	for (i = 0, walker = hash_first(hid); walker; walker = hash_next(hid)) {
	408	printf("item %5d: key: '%s' item: %p\n", i++, walker->key,
	409	walker->item);
	410	}
	411	printf("done walking hash table...\n");
	412
	413
	414	printf("driver finished.\n");
	415	exit(0);
	416	}
	417	#endif