src/glx/glxhash.c - platform/external/mesa3d - Gitiles

 /* glxhash.c -- Small hash table support for integer -> integer mapping
  * Taken from libdrm.
  *
  * Created: Sun Apr 18 09:35:45 1999 by faith@precisioninsight.com
  *
  * Copyright 1999 Precision Insight, Inc., Cedar Park, Texas.
  * All Rights Reserved.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the "Software"),
  * to deal in the Software without restriction, including without limitation
  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  * and/or sell copies of the Software, and to permit persons to whom the
  * Software is furnished to do so, subject to the following conditions:
  *
  * The above copyright notice and this permission notice (including the next
  * paragraph) shall be included in all copies or substantial portions of the
  * Software.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  * PRECISION INSIGHT AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  * DEALINGS IN THE SOFTWARE.
  *
  * Authors: Rickard E. (Rik) Faith <faith@valinux.com>
  *
  * DESCRIPTION
  *
  * This file contains a straightforward implementation of a fixed-sized
  * hash table using self-organizing linked lists [Knuth73, pp. 398-399] for
  * collision resolution.  There are two potentially interesting things
  * about this implementation:
  *
  * 1) The table is power-of-two sized.  Prime sized tables are more
  * traditional, but do not have a significant advantage over power-of-two
  * sized table, especially when double hashing is not used for collision
  * resolution.
  *
  * 2) The hash computation uses a table of random integers [Hanson97,
  * pp. 39-41].
  *
  * FUTURE ENHANCEMENTS
  *
  * With a table size of 512, the current implementation is sufficient for a
  * few hundred keys.  Since this is well above the expected size of the
  * tables for which this implementation was designed, the implementation of
  * dynamic hash tables was postponed until the need arises.  A common (and
  * naive) approach to dynamic hash table implementation simply creates a
  * new hash table when necessary, rehashes all the data into the new table,
  * and destroys the old table.  The approach in [Larson88] is superior in
  * two ways: 1) only a portion of the table is expanded when needed,
  * distributing the expansion cost over several insertions, and 2) portions
  * of the table can be locked, enabling a scalable thread-safe
  * implementation.
  *
  * REFERENCES
  *
  * [Hanson97] David R. Hanson.  C Interfaces and Implementations:
  * Techniques for Creating Reusable Software.  Reading, Massachusetts:
  * Addison-Wesley, 1997.
  *
  * [Knuth73] Donald E. Knuth. The Art of Computer Programming.  Volume 3:
  * Sorting and Searching.  Reading, Massachusetts: Addison-Wesley, 1973.
  *
  * [Larson88] Per-Ake Larson. "Dynamic Hash Tables".  CACM 31(4), April
  * 1988, pp. 446-457.
  *
  */

 #include "glxhash.h"
 #include <X11/Xfuncproto.h>

 #define HASH_MAIN 0

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

 #define HASH_MAGIC 0xdeadbeef
 #define HASH_DEBUG 0
 #define HASH_SIZE  512          /* Good for about 100 entries */
                                 /* If you change this value, you probably
                                    have to change the HashHash hashing
                                    function! */

 #define HASH_ALLOC malloc
 #define HASH_FREE  free
 #ifndef HAVE_RANDOM_R
 #define HASH_RANDOM_DECL	char *ps, rs[256]
 #define HASH_RANDOM_INIT(seed)	ps = initstate(seed, rs, sizeof(rs))
 #define HASH_RANDOM		random()
 #define HASH_RANDOM_DESTROY	setstate(ps)
 #else
 #define HASH_RANDOM_DECL	struct random_data rd; int32_t rv; char rs[256]
 #define HASH_RANDOM_INIT(seed)					\
    do {								\
       (void) memset(&rd, 0, sizeof(rd));			\
       (void) initstate_r(seed, rs, sizeof(rs), &rd);		\
    } while(0)
 #define HASH_RANDOM             ((void) random_r(&rd, &rv), rv)
 #define HASH_RANDOM_DESTROY
 #endif

 typedef struct __glxHashBucket
 {
    unsigned long key;
    void *value;
    struct __glxHashBucket *next;
 } __glxHashBucket, *__glxHashBucketPtr;

 typedef struct __glxHashTable *__glxHashTablePtr;
 struct __glxHashTable
 {
    unsigned long magic;
    unsigned long hits;          /* At top of linked list */
    unsigned long partials;      /* Not at top of linked list */
    unsigned long misses;        /* Not in table */
    __glxHashBucketPtr buckets[HASH_SIZE];
    int p0;
    __glxHashBucketPtr p1;
 };

 static unsigned long
 HashHash(unsigned long key)
 {
    unsigned long hash = 0;
    unsigned long tmp = key;
    static int init = 0;
    static unsigned long scatter[256];
    int i;

    if (!init) {
       HASH_RANDOM_DECL;
       HASH_RANDOM_INIT(37);
       for (i = 0; i < 256; i++)
          scatter[i] = HASH_RANDOM;
       HASH_RANDOM_DESTROY;
       ++init;
    }

    while (tmp) {
       hash = (hash << 1) + scatter[tmp & 0xff];
       tmp >>= 8;
    }

    hash %= HASH_SIZE;
 #if HASH_DEBUG
    printf("Hash(%d) = %d\n", key, hash);
 #endif
    return hash;
 }

 _X_HIDDEN __glxHashTable *
 __glxHashCreate(void)
 {
    __glxHashTablePtr table;
    int i;

    table = HASH_ALLOC(sizeof(*table));
    if (!table)
       return NULL;
    table->magic = HASH_MAGIC;
    table->hits = 0;
    table->partials = 0;
    table->misses = 0;

    for (i = 0; i < HASH_SIZE; i++)
       table->buckets[i] = NULL;
    return table;
 }

 _X_HIDDEN int
 __glxHashDestroy(__glxHashTable * t)
 {
    __glxHashTablePtr table = (__glxHashTablePtr) t;
    __glxHashBucketPtr bucket;
    __glxHashBucketPtr next;
    int i;

    if (table->magic != HASH_MAGIC)
       return -1;                /* Bad magic */

    for (i = 0; i < HASH_SIZE; i++) {
       for (bucket = table->buckets[i]; bucket;) {
          next = bucket->next;
          HASH_FREE(bucket);
          bucket = next;
       }
    }
    HASH_FREE(table);
    return 0;
 }

 /* Find the bucket and organize the list so that this bucket is at the
    top. */

 static __glxHashBucketPtr
 HashFind(__glxHashTablePtr table, unsigned long key, unsigned long *h)
 {
    unsigned long hash = HashHash(key);
    __glxHashBucketPtr prev = NULL;
    __glxHashBucketPtr bucket;

    if (h)
       *h = hash;

    for (bucket = table->buckets[hash]; bucket; bucket = bucket->next) {
       if (bucket->key == key) {
          if (prev) {
             /* Organize */
             prev->next = bucket->next;
             bucket->next = table->buckets[hash];
             table->buckets[hash] = bucket;
             ++table->partials;
          }
          else {
             ++table->hits;
          }
          return bucket;
       }
       prev = bucket;
    }
    ++table->misses;
    return NULL;
 }

 _X_HIDDEN int
 __glxHashLookup(__glxHashTable * t, unsigned long key, void **value)
 {
    __glxHashTablePtr table = (__glxHashTablePtr) t;
    __glxHashBucketPtr bucket;

    if (!table || table->magic != HASH_MAGIC)
       return -1;                /* Bad magic */

    bucket = HashFind(table, key, NULL);
    if (!bucket)
       return 1;                 /* Not found */
    *value = bucket->value;
    return 0;                    /* Found */
 }

 _X_HIDDEN int
 __glxHashInsert(__glxHashTable * t, unsigned long key, void *value)
 {
    __glxHashTablePtr table = (__glxHashTablePtr) t;
    __glxHashBucketPtr bucket;
    unsigned long hash;

    if (table->magic != HASH_MAGIC)
       return -1;                /* Bad magic */

    if (HashFind(table, key, &hash))
       return 1;                 /* Already in table */

    bucket = HASH_ALLOC(sizeof(*bucket));
    if (!bucket)
       return -1;                /* Error */
    bucket->key = key;
    bucket->value = value;
    bucket->next = table->buckets[hash];
    table->buckets[hash] = bucket;
 #if HASH_DEBUG
    printf("Inserted %d at %d/%p\n", key, hash, bucket);
 #endif
    return 0;                    /* Added to table */
 }

 _X_HIDDEN int
 __glxHashDelete(__glxHashTable * t, unsigned long key)
 {
    __glxHashTablePtr table = (__glxHashTablePtr) t;
    unsigned long hash;
    __glxHashBucketPtr bucket;

    if (table->magic != HASH_MAGIC)
       return -1;                /* Bad magic */

    bucket = HashFind(table, key, &hash);

    if (!bucket)
       return 1;                 /* Not found */

    table->buckets[hash] = bucket->next;
    HASH_FREE(bucket);
    return 0;
 }

 _X_HIDDEN int
 __glxHashNext(__glxHashTable * t, unsigned long *key, void **value)
 {
    __glxHashTablePtr table = (__glxHashTablePtr) t;

    while (table->p0 < HASH_SIZE) {
       if (table->p1) {
          *key = table->p1->key;
          *value = table->p1->value;
          table->p1 = table->p1->next;
          return 1;
       }
       table->p1 = table->buckets[table->p0];
       ++table->p0;
    }
    return 0;
 }

 _X_HIDDEN int
 __glxHashFirst(__glxHashTable * t, unsigned long *key, void **value)
 {
    __glxHashTablePtr table = (__glxHashTablePtr) t;

    if (table->magic != HASH_MAGIC)
       return -1;                /* Bad magic */

    table->p0 = 0;
    table->p1 = table->buckets[0];
    return __glxHashNext(table, key, value);
 }

 #if HASH_MAIN
 #define DIST_LIMIT 10
 static int dist[DIST_LIMIT];

 static void
 clear_dist(void)
 {
    int i;

    for (i = 0; i < DIST_LIMIT; i++)
       dist[i] = 0;
 }

 static int
 count_entries(__glxHashBucketPtr bucket)
 {
    int count = 0;

    for (; bucket; bucket = bucket->next)
       ++count;
    return count;
 }

 static void
 update_dist(int count)
 {
    if (count >= DIST_LIMIT)
       ++dist[DIST_LIMIT - 1];
    else
       ++dist[count];
 }

 static void
 compute_dist(__glxHashTablePtr table)
 {
    int i;
    __glxHashBucketPtr bucket;

    printf("Hits = %ld, partials = %ld, misses = %ld\n",
           table->hits, table->partials, table->misses);
    clear_dist();
    for (i = 0; i < HASH_SIZE; i++) {
       bucket = table->buckets[i];
       update_dist(count_entries(bucket));
    }
    for (i = 0; i < DIST_LIMIT; i++) {
       if (i != DIST_LIMIT - 1)
          printf("%5d %10d\n", i, dist[i]);
       else
          printf("other %10d\n", dist[i]);
    }
 }

 static void
 check_table(__glxHashTablePtr table, unsigned long key, unsigned long value)
 {
    unsigned long retval = 0;
    int retcode = __glxHashLookup(table, key, &retval);

    switch (retcode) {
    case -1:
       printf("Bad magic = 0x%08lx:"
              " key = %lu, expected = %lu, returned = %lu\n",
              table->magic, key, value, retval);
       break;
    case 1:
       printf("Not found: key = %lu, expected = %lu returned = %lu\n",
              key, value, retval);
       break;
    case 0:
       if (value != retval)
          printf("Bad value: key = %lu, expected = %lu, returned = %lu\n",
                 key, value, retval);
       break;
    default:
       printf("Bad retcode = %d: key = %lu, expected = %lu, returned = %lu\n",
              retcode, key, value, retval);
       break;
    }
 }

 int
 main(void)
 {
    __glxHashTablePtr table;
    int i;

    printf("\n***** 256 consecutive integers ****\n");
    table = __glxHashCreate();
    for (i = 0; i < 256; i++)
       __glxHashInsert(table, i, i);
    for (i = 0; i < 256; i++)
       check_table(table, i, i);
    for (i = 256; i >= 0; i--)
       check_table(table, i, i);
    compute_dist(table);
    __glxHashDestroy(table);

    printf("\n***** 1024 consecutive integers ****\n");
    table = __glxHashCreate();
    for (i = 0; i < 1024; i++)
       __glxHashInsert(table, i, i);
    for (i = 0; i < 1024; i++)
       check_table(table, i, i);
    for (i = 1024; i >= 0; i--)
       check_table(table, i, i);
    compute_dist(table);
    __glxHashDestroy(table);

    printf("\n***** 1024 consecutive page addresses (4k pages) ****\n");
    table = __glxHashCreate();
    for (i = 0; i < 1024; i++)
       __glxHashInsert(table, i * 4096, i);
    for (i = 0; i < 1024; i++)
       check_table(table, i * 4096, i);
    for (i = 1024; i >= 0; i--)
       check_table(table, i * 4096, i);
    compute_dist(table);
    __glxHashDestroy(table);

    printf("\n***** 1024 random integers ****\n");
    table = __glxHashCreate();
    srandom(0xbeefbeef);
    for (i = 0; i < 1024; i++)
       __glxHashInsert(table, random(), i);
    srandom(0xbeefbeef);
    for (i = 0; i < 1024; i++)
       check_table(table, random(), i);
    srandom(0xbeefbeef);
    for (i = 0; i < 1024; i++)
       check_table(table, random(), i);
    compute_dist(table);
    __glxHashDestroy(table);

    printf("\n***** 5000 random integers ****\n");
    table = __glxHashCreate();
    srandom(0xbeefbeef);
    for (i = 0; i < 5000; i++)
       __glxHashInsert(table, random(), i);
    srandom(0xbeefbeef);
    for (i = 0; i < 5000; i++)
       check_table(table, random(), i);
    srandom(0xbeefbeef);
    for (i = 0; i < 5000; i++)
       check_table(table, random(), i);
    compute_dist(table);
    __glxHashDestroy(table);

    return 0;
 }
 #endif
	/* glxhash.c -- Small hash table support for integer -> integer mapping
	* Taken from libdrm.
	*
	* Created: Sun Apr 18 09:35:45 1999 by faith@precisioninsight.com
	*
	* Copyright 1999 Precision Insight, Inc., Cedar Park, Texas.
	* All Rights Reserved.
	*
	* Permission is hereby granted, free of charge, to any person obtaining a
	* copy of this software and associated documentation files (the "Software"),
	* to deal in the Software without restriction, including without limitation
	* the rights to use, copy, modify, merge, publish, distribute, sublicense,
	* and/or sell copies of the Software, and to permit persons to whom the
	* Software is furnished to do so, subject to the following conditions:
	*
	* The above copyright notice and this permission notice (including the next
	* paragraph) shall be included in all copies or substantial portions of the
	* Software.
	*
	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
	* PRECISION INSIGHT AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
	* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
	* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
	* DEALINGS IN THE SOFTWARE.
	*
	* Authors: Rickard E. (Rik) Faith <faith@valinux.com>
	*
	* DESCRIPTION
	*
	* This file contains a straightforward implementation of a fixed-sized
	* hash table using self-organizing linked lists [Knuth73, pp. 398-399] for
	* collision resolution. There are two potentially interesting things
	* about this implementation:
	*
	* 1) The table is power-of-two sized. Prime sized tables are more
	* traditional, but do not have a significant advantage over power-of-two
	* sized table, especially when double hashing is not used for collision
	* resolution.
	*
	* 2) The hash computation uses a table of random integers [Hanson97,
	* pp. 39-41].
	*
	* FUTURE ENHANCEMENTS
	*
	* With a table size of 512, the current implementation is sufficient for a
	* few hundred keys. Since this is well above the expected size of the
	* tables for which this implementation was designed, the implementation of
	* dynamic hash tables was postponed until the need arises. A common (and
	* naive) approach to dynamic hash table implementation simply creates a
	* new hash table when necessary, rehashes all the data into the new table,
	* and destroys the old table. The approach in [Larson88] is superior in
	* two ways: 1) only a portion of the table is expanded when needed,
	* distributing the expansion cost over several insertions, and 2) portions
	* of the table can be locked, enabling a scalable thread-safe
	* implementation.
	*
	* REFERENCES
	*
	* [Hanson97] David R. Hanson. C Interfaces and Implementations:
	* Techniques for Creating Reusable Software. Reading, Massachusetts:
	* Addison-Wesley, 1997.
	*
	* [Knuth73] Donald E. Knuth. The Art of Computer Programming. Volume 3:
	* Sorting and Searching. Reading, Massachusetts: Addison-Wesley, 1973.
	*
	* [Larson88] Per-Ake Larson. "Dynamic Hash Tables". CACM 31(4), April
	* 1988, pp. 446-457.
	*
	*/

	#include "glxhash.h"
	#include <X11/Xfuncproto.h>

	#define HASH_MAIN 0

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

	#define HASH_MAGIC 0xdeadbeef
	#define HASH_DEBUG 0
	#define HASH_SIZE 512 /* Good for about 100 entries */
	/* If you change this value, you probably
	have to change the HashHash hashing
	function! */

	#define HASH_ALLOC malloc
	#define HASH_FREE free
	#ifndef HAVE_RANDOM_R
	#define HASH_RANDOM_DECL char *ps, rs[256]
	#define HASH_RANDOM_INIT(seed) ps = initstate(seed, rs, sizeof(rs))
	#define HASH_RANDOM random()
	#define HASH_RANDOM_DESTROY setstate(ps)
	#else
	#define HASH_RANDOM_DECL struct random_data rd; int32_t rv; char rs[256]
	#define HASH_RANDOM_INIT(seed) \
	do { \
	(void) memset(&rd, 0, sizeof(rd)); \
	(void) initstate_r(seed, rs, sizeof(rs), &rd); \
	} while(0)
	#define HASH_RANDOM ((void) random_r(&rd, &rv), rv)
	#define HASH_RANDOM_DESTROY
	#endif

	typedef struct __glxHashBucket
	{
	unsigned long key;
	void *value;
	struct __glxHashBucket *next;
	} __glxHashBucket, *__glxHashBucketPtr;

	typedef struct __glxHashTable *__glxHashTablePtr;
	struct __glxHashTable
	{
	unsigned long magic;
	unsigned long hits; /* At top of linked list */
	unsigned long partials; /* Not at top of linked list */
	unsigned long misses; /* Not in table */
	__glxHashBucketPtr buckets[HASH_SIZE];
	int p0;
	__glxHashBucketPtr p1;
	};

	static unsigned long
	HashHash(unsigned long key)
	{
	unsigned long hash = 0;
	unsigned long tmp = key;
	static int init = 0;
	static unsigned long scatter[256];
	int i;

	if (!init) {
	HASH_RANDOM_DECL;
	HASH_RANDOM_INIT(37);
	for (i = 0; i < 256; i++)
	scatter[i] = HASH_RANDOM;
	HASH_RANDOM_DESTROY;
	++init;
	}

	while (tmp) {
	hash = (hash << 1) + scatter[tmp & 0xff];
	tmp >>= 8;
	}

	hash %= HASH_SIZE;
	#if HASH_DEBUG
	printf("Hash(%d) = %d\n", key, hash);
	#endif
	return hash;
	}

	_X_HIDDEN __glxHashTable *
	__glxHashCreate(void)
	{
	__glxHashTablePtr table;
	int i;

	table = HASH_ALLOC(sizeof(*table));
	if (!table)
	return NULL;
	table->magic = HASH_MAGIC;
	table->hits = 0;
	table->partials = 0;
	table->misses = 0;

	for (i = 0; i < HASH_SIZE; i++)
	table->buckets[i] = NULL;
	return table;
	}

	_X_HIDDEN int
	__glxHashDestroy(__glxHashTable * t)
	{
	__glxHashTablePtr table = (__glxHashTablePtr) t;
	__glxHashBucketPtr bucket;
	__glxHashBucketPtr next;
	int i;

	if (table->magic != HASH_MAGIC)
	return -1; /* Bad magic */

	for (i = 0; i < HASH_SIZE; i++) {
	for (bucket = table->buckets[i]; bucket;) {
	next = bucket->next;
	HASH_FREE(bucket);
	bucket = next;
	}
	}
	HASH_FREE(table);
	return 0;
	}

	/* Find the bucket and organize the list so that this bucket is at the
	top. */

	static __glxHashBucketPtr
	HashFind(__glxHashTablePtr table, unsigned long key, unsigned long *h)
	{
	unsigned long hash = HashHash(key);
	__glxHashBucketPtr prev = NULL;
	__glxHashBucketPtr bucket;

	if (h)
	*h = hash;

	for (bucket = table->buckets[hash]; bucket; bucket = bucket->next) {
	if (bucket->key == key) {
	if (prev) {
	/* Organize */
	prev->next = bucket->next;
	bucket->next = table->buckets[hash];
	table->buckets[hash] = bucket;
	++table->partials;
	}
	else {
	++table->hits;
	}
	return bucket;
	}
	prev = bucket;
	}
	++table->misses;
	return NULL;
	}

	_X_HIDDEN int
	__glxHashLookup(__glxHashTable * t, unsigned long key, void **value)
	{
	__glxHashTablePtr table = (__glxHashTablePtr) t;
	__glxHashBucketPtr bucket;

	if (!table \|\| table->magic != HASH_MAGIC)
	return -1; /* Bad magic */

	bucket = HashFind(table, key, NULL);
	if (!bucket)
	return 1; /* Not found */
	*value = bucket->value;
	return 0; /* Found */
	}

	_X_HIDDEN int
	__glxHashInsert(__glxHashTable * t, unsigned long key, void *value)
	{
	__glxHashTablePtr table = (__glxHashTablePtr) t;
	__glxHashBucketPtr bucket;
	unsigned long hash;

	if (table->magic != HASH_MAGIC)
	return -1; /* Bad magic */

	if (HashFind(table, key, &hash))
	return 1; /* Already in table */

	bucket = HASH_ALLOC(sizeof(*bucket));
	if (!bucket)
	return -1; /* Error */
	bucket->key = key;
	bucket->value = value;
	bucket->next = table->buckets[hash];
	table->buckets[hash] = bucket;
	#if HASH_DEBUG
	printf("Inserted %d at %d/%p\n", key, hash, bucket);
	#endif
	return 0; /* Added to table */
	}

	_X_HIDDEN int
	__glxHashDelete(__glxHashTable * t, unsigned long key)
	{
	__glxHashTablePtr table = (__glxHashTablePtr) t;
	unsigned long hash;
	__glxHashBucketPtr bucket;

	if (table->magic != HASH_MAGIC)
	return -1; /* Bad magic */

	bucket = HashFind(table, key, &hash);

	if (!bucket)
	return 1; /* Not found */

	table->buckets[hash] = bucket->next;
	HASH_FREE(bucket);
	return 0;
	}

	_X_HIDDEN int
	__glxHashNext(__glxHashTable * t, unsigned long key, void *value)
	{
	__glxHashTablePtr table = (__glxHashTablePtr) t;

	while (table->p0 < HASH_SIZE) {
	if (table->p1) {
	*key = table->p1->key;
	*value = table->p1->value;
	table->p1 = table->p1->next;
	return 1;
	}
	table->p1 = table->buckets[table->p0];
	++table->p0;
	}
	return 0;
	}

	_X_HIDDEN int
	__glxHashFirst(__glxHashTable * t, unsigned long key, void *value)
	{
	__glxHashTablePtr table = (__glxHashTablePtr) t;

	if (table->magic != HASH_MAGIC)
	return -1; /* Bad magic */

	table->p0 = 0;
	table->p1 = table->buckets[0];
	return __glxHashNext(table, key, value);
	}

	#if HASH_MAIN
	#define DIST_LIMIT 10
	static int dist[DIST_LIMIT];

	static void
	clear_dist(void)
	{
	int i;

	for (i = 0; i < DIST_LIMIT; i++)
	dist[i] = 0;
	}

	static int
	count_entries(__glxHashBucketPtr bucket)
	{
	int count = 0;

	for (; bucket; bucket = bucket->next)
	++count;
	return count;
	}

	static void
	update_dist(int count)
	{
	if (count >= DIST_LIMIT)
	++dist[DIST_LIMIT - 1];
	else
	++dist[count];
	}

	static void
	compute_dist(__glxHashTablePtr table)
	{
	int i;
	__glxHashBucketPtr bucket;

	printf("Hits = %ld, partials = %ld, misses = %ld\n",
	table->hits, table->partials, table->misses);
	clear_dist();
	for (i = 0; i < HASH_SIZE; i++) {
	bucket = table->buckets[i];
	update_dist(count_entries(bucket));
	}
	for (i = 0; i < DIST_LIMIT; i++) {
	if (i != DIST_LIMIT - 1)
	printf("%5d %10d\n", i, dist[i]);
	else
	printf("other %10d\n", dist[i]);
	}
	}

	static void
	check_table(__glxHashTablePtr table, unsigned long key, unsigned long value)
	{
	unsigned long retval = 0;
	int retcode = __glxHashLookup(table, key, &retval);

	switch (retcode) {
	case -1:
	printf("Bad magic = 0x%08lx:"
	" key = %lu, expected = %lu, returned = %lu\n",
	table->magic, key, value, retval);
	break;
	case 1:
	printf("Not found: key = %lu, expected = %lu returned = %lu\n",
	key, value, retval);
	break;
	case 0:
	if (value != retval)
	printf("Bad value: key = %lu, expected = %lu, returned = %lu\n",
	key, value, retval);
	break;
	default:
	printf("Bad retcode = %d: key = %lu, expected = %lu, returned = %lu\n",
	retcode, key, value, retval);
	break;
	}
	}

	int
	main(void)
	{
	__glxHashTablePtr table;
	int i;

	printf("\n*** 256 consecutive integers **\n");
	table = __glxHashCreate();
	for (i = 0; i < 256; i++)
	__glxHashInsert(table, i, i);
	for (i = 0; i < 256; i++)
	check_table(table, i, i);
	for (i = 256; i >= 0; i--)
	check_table(table, i, i);
	compute_dist(table);
	__glxHashDestroy(table);

	printf("\n*** 1024 consecutive integers **\n");
	table = __glxHashCreate();
	for (i = 0; i < 1024; i++)
	__glxHashInsert(table, i, i);
	for (i = 0; i < 1024; i++)
	check_table(table, i, i);
	for (i = 1024; i >= 0; i--)
	check_table(table, i, i);
	compute_dist(table);
	__glxHashDestroy(table);

	printf("\n*** 1024 consecutive page addresses (4k pages) **\n");
	table = __glxHashCreate();
	for (i = 0; i < 1024; i++)
	__glxHashInsert(table, i * 4096, i);
	for (i = 0; i < 1024; i++)
	check_table(table, i * 4096, i);
	for (i = 1024; i >= 0; i--)
	check_table(table, i * 4096, i);
	compute_dist(table);
	__glxHashDestroy(table);

	printf("\n*** 1024 random integers **\n");
	table = __glxHashCreate();
	srandom(0xbeefbeef);
	for (i = 0; i < 1024; i++)
	__glxHashInsert(table, random(), i);
	srandom(0xbeefbeef);
	for (i = 0; i < 1024; i++)
	check_table(table, random(), i);
	srandom(0xbeefbeef);
	for (i = 0; i < 1024; i++)
	check_table(table, random(), i);
	compute_dist(table);
	__glxHashDestroy(table);

	printf("\n*** 5000 random integers **\n");
	table = __glxHashCreate();
	srandom(0xbeefbeef);
	for (i = 0; i < 5000; i++)
	__glxHashInsert(table, random(), i);
	srandom(0xbeefbeef);
	for (i = 0; i < 5000; i++)
	check_table(table, random(), i);
	srandom(0xbeefbeef);
	for (i = 0; i < 5000; i++)
	check_table(table, random(), i);
	compute_dist(table);
	__glxHashDestroy(table);

	return 0;
	}
	#endif