331 lines
6.8 KiB
C
331 lines
6.8 KiB
C
/* $OpenBSD: src/lib/libutil/ohash.c,v 1.1 2014/06/02 18:52:03 deraadt Exp $ */
|
|
|
|
/* Copyright (c) 1999, 2004 Marc Espie <espie@openbsd.org>
|
|
*
|
|
* Permission to use, copy, modify, and distribute this software for any
|
|
* purpose with or without fee is hereby granted, provided that the above
|
|
* copyright notice and this permission notice appear in all copies.
|
|
*
|
|
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
|
|
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
|
|
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
|
|
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
|
|
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
|
|
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
|
|
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
|
|
*/
|
|
|
|
#include <sys/cdefs.h>
|
|
__FBSDID("$FreeBSD$");
|
|
|
|
#include <stddef.h>
|
|
#include <stdint.h>
|
|
#include <stdlib.h>
|
|
#include <string.h>
|
|
#include <limits.h>
|
|
#include "ohash.h"
|
|
|
|
struct _ohash_record {
|
|
uint32_t hv;
|
|
const char *p;
|
|
};
|
|
|
|
#define DELETED ((const char *)h)
|
|
#define NONE (h->size)
|
|
|
|
/* Don't bother changing the hash table if the change is small enough. */
|
|
#define MINSIZE (1UL << 4)
|
|
#define MINDELETED 4
|
|
|
|
static void ohash_resize(struct ohash *);
|
|
|
|
|
|
/* This handles the common case of variable length keys, where the
|
|
* key is stored at the end of the record.
|
|
*/
|
|
void *
|
|
ohash_create_entry(struct ohash_info *i, const char *start, const char **end)
|
|
{
|
|
char *p;
|
|
|
|
if (!*end)
|
|
*end = start + strlen(start);
|
|
p = (i->alloc)(i->key_offset + (*end - start) + 1, i->data);
|
|
if (p) {
|
|
memcpy(p+i->key_offset, start, *end-start);
|
|
p[i->key_offset + (*end - start)] = '\0';
|
|
}
|
|
return (void *)p;
|
|
}
|
|
|
|
/* hash_delete only frees the hash structure. Use hash_first/hash_next
|
|
* to free entries as well. */
|
|
void
|
|
ohash_delete(struct ohash *h)
|
|
{
|
|
(h->info.free)(h->t, h->info.data);
|
|
#ifndef NDEBUG
|
|
h->t = NULL;
|
|
#endif
|
|
}
|
|
|
|
static void
|
|
ohash_resize(struct ohash *h)
|
|
{
|
|
struct _ohash_record *n;
|
|
size_t ns;
|
|
unsigned int j;
|
|
unsigned int i, incr;
|
|
|
|
if (4 * h->deleted < h->total) {
|
|
if (h->size >= (UINT_MAX >> 1U))
|
|
ns = UINT_MAX;
|
|
else
|
|
ns = h->size << 1U;
|
|
} else if (3 * h->deleted > 2 * h->total)
|
|
ns = h->size >> 1U;
|
|
else
|
|
ns = h->size;
|
|
if (ns < MINSIZE)
|
|
ns = MINSIZE;
|
|
#ifdef STATS_HASH
|
|
STAT_HASH_EXPAND++;
|
|
STAT_HASH_SIZE += ns - h->size;
|
|
#endif
|
|
|
|
n = (h->info.calloc)(ns, sizeof(struct _ohash_record), h->info.data);
|
|
if (!n)
|
|
return;
|
|
|
|
for (j = 0; j < h->size; j++) {
|
|
if (h->t[j].p != NULL && h->t[j].p != DELETED) {
|
|
i = h->t[j].hv % ns;
|
|
incr = ((h->t[j].hv % (ns - 2)) & ~1) + 1;
|
|
while (n[i].p != NULL) {
|
|
i += incr;
|
|
if (i >= ns)
|
|
i -= ns;
|
|
}
|
|
n[i].hv = h->t[j].hv;
|
|
n[i].p = h->t[j].p;
|
|
}
|
|
}
|
|
(h->info.free)(h->t, h->info.data);
|
|
h->t = n;
|
|
h->size = ns;
|
|
h->total -= h->deleted;
|
|
h->deleted = 0;
|
|
}
|
|
|
|
void *
|
|
ohash_remove(struct ohash *h, unsigned int i)
|
|
{
|
|
void *result = (void *)h->t[i].p;
|
|
|
|
if (result == NULL || result == DELETED)
|
|
return NULL;
|
|
|
|
#ifdef STATS_HASH
|
|
STAT_HASH_ENTRIES--;
|
|
#endif
|
|
h->t[i].p = DELETED;
|
|
h->deleted++;
|
|
if (h->deleted >= MINDELETED && 4 * h->deleted > h->total)
|
|
ohash_resize(h);
|
|
return result;
|
|
}
|
|
|
|
void *
|
|
ohash_find(struct ohash *h, unsigned int i)
|
|
{
|
|
if (h->t[i].p == DELETED)
|
|
return NULL;
|
|
else
|
|
return (void *)h->t[i].p;
|
|
}
|
|
|
|
void *
|
|
ohash_insert(struct ohash *h, unsigned int i, void *p)
|
|
{
|
|
#ifdef STATS_HASH
|
|
STAT_HASH_ENTRIES++;
|
|
#endif
|
|
if (h->t[i].p == DELETED) {
|
|
h->deleted--;
|
|
h->t[i].p = p;
|
|
} else {
|
|
h->t[i].p = p;
|
|
/* Arbitrary resize boundary. Tweak if not efficient enough. */
|
|
if (++h->total * 4 > h->size * 3)
|
|
ohash_resize(h);
|
|
}
|
|
return p;
|
|
}
|
|
|
|
unsigned int
|
|
ohash_entries(struct ohash *h)
|
|
{
|
|
return h->total - h->deleted;
|
|
}
|
|
|
|
void *
|
|
ohash_first(struct ohash *h, unsigned int *pos)
|
|
{
|
|
*pos = 0;
|
|
return ohash_next(h, pos);
|
|
}
|
|
|
|
void *
|
|
ohash_next(struct ohash *h, unsigned int *pos)
|
|
{
|
|
for (; *pos < h->size; (*pos)++)
|
|
if (h->t[*pos].p != DELETED && h->t[*pos].p != NULL)
|
|
return (void *)h->t[(*pos)++].p;
|
|
return NULL;
|
|
}
|
|
|
|
void
|
|
ohash_init(struct ohash *h, unsigned int size, struct ohash_info *info)
|
|
{
|
|
h->size = 1UL << size;
|
|
if (h->size < MINSIZE)
|
|
h->size = MINSIZE;
|
|
#ifdef STATS_HASH
|
|
STAT_HASH_CREATION++;
|
|
STAT_HASH_SIZE += h->size;
|
|
#endif
|
|
/* Copy info so that caller may free it. */
|
|
h->info.key_offset = info->key_offset;
|
|
h->info.calloc = info->calloc;
|
|
h->info.free = info->free;
|
|
h->info.alloc = info->alloc;
|
|
h->info.data = info->data;
|
|
h->t = (h->info.calloc)(h->size, sizeof(struct _ohash_record),
|
|
h->info.data);
|
|
h->total = h->deleted = 0;
|
|
}
|
|
|
|
uint32_t
|
|
ohash_interval(const char *s, const char **e)
|
|
{
|
|
uint32_t k;
|
|
|
|
if (!*e)
|
|
*e = s + strlen(s);
|
|
if (s == *e)
|
|
k = 0;
|
|
else
|
|
k = *s++;
|
|
while (s != *e)
|
|
k = ((k << 2) | (k >> 30)) ^ *s++;
|
|
return k;
|
|
}
|
|
|
|
unsigned int
|
|
ohash_lookup_interval(struct ohash *h, const char *start, const char *end,
|
|
uint32_t hv)
|
|
{
|
|
unsigned int i, incr;
|
|
unsigned int empty;
|
|
|
|
#ifdef STATS_HASH
|
|
STAT_HASH_LOOKUP++;
|
|
#endif
|
|
empty = NONE;
|
|
i = hv % h->size;
|
|
incr = ((hv % (h->size-2)) & ~1) + 1;
|
|
while (h->t[i].p != NULL) {
|
|
#ifdef STATS_HASH
|
|
STAT_HASH_LENGTH++;
|
|
#endif
|
|
if (h->t[i].p == DELETED) {
|
|
if (empty == NONE)
|
|
empty = i;
|
|
} else if (h->t[i].hv == hv &&
|
|
strncmp(h->t[i].p+h->info.key_offset, start,
|
|
end - start) == 0 &&
|
|
(h->t[i].p+h->info.key_offset)[end-start] == '\0') {
|
|
if (empty != NONE) {
|
|
h->t[empty].hv = hv;
|
|
h->t[empty].p = h->t[i].p;
|
|
h->t[i].p = DELETED;
|
|
return empty;
|
|
} else {
|
|
#ifdef STATS_HASH
|
|
STAT_HASH_POSITIVE++;
|
|
#endif
|
|
return i;
|
|
}
|
|
}
|
|
i += incr;
|
|
if (i >= h->size)
|
|
i -= h->size;
|
|
}
|
|
|
|
/* Found an empty position. */
|
|
if (empty != NONE)
|
|
i = empty;
|
|
h->t[i].hv = hv;
|
|
return i;
|
|
}
|
|
|
|
unsigned int
|
|
ohash_lookup_memory(struct ohash *h, const char *k, size_t size, uint32_t hv)
|
|
{
|
|
unsigned int i, incr;
|
|
unsigned int empty;
|
|
|
|
#ifdef STATS_HASH
|
|
STAT_HASH_LOOKUP++;
|
|
#endif
|
|
empty = NONE;
|
|
i = hv % h->size;
|
|
incr = ((hv % (h->size-2)) & ~1) + 1;
|
|
while (h->t[i].p != NULL) {
|
|
#ifdef STATS_HASH
|
|
STAT_HASH_LENGTH++;
|
|
#endif
|
|
if (h->t[i].p == DELETED) {
|
|
if (empty == NONE)
|
|
empty = i;
|
|
} else if (h->t[i].hv == hv &&
|
|
memcmp(h->t[i].p+h->info.key_offset, k, size) == 0) {
|
|
if (empty != NONE) {
|
|
h->t[empty].hv = hv;
|
|
h->t[empty].p = h->t[i].p;
|
|
h->t[i].p = DELETED;
|
|
return empty;
|
|
} else {
|
|
#ifdef STATS_HASH
|
|
STAT_HASH_POSITIVE++;
|
|
#endif
|
|
} return i;
|
|
}
|
|
i += incr;
|
|
if (i >= h->size)
|
|
i -= h->size;
|
|
}
|
|
|
|
/* Found an empty position. */
|
|
if (empty != NONE)
|
|
i = empty;
|
|
h->t[i].hv = hv;
|
|
return i;
|
|
}
|
|
|
|
unsigned int
|
|
ohash_qlookup(struct ohash *h, const char *s)
|
|
{
|
|
const char *e = NULL;
|
|
return ohash_qlookupi(h, s, &e);
|
|
}
|
|
|
|
unsigned int
|
|
ohash_qlookupi(struct ohash *h, const char *s, const char **e)
|
|
{
|
|
uint32_t hv;
|
|
|
|
hv = ohash_interval(s, e);
|
|
return ohash_lookup_interval(h, s, *e, hv);
|
|
}
|