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author | Christian Neukirchen <chneukirchen@gmail.com> | 2014-07-31 16:09:53 +0200 |
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committer | Christian Neukirchen <chneukirchen@gmail.com> | 2014-07-31 16:09:53 +0200 |
commit | 879d51525932a2ba2841744ed302c170b5dc8270 (patch) | |
tree | 003d31fb6c5e7e8e1654ef07247215be93dfa960 /src/liboutils/ohash.c | |
parent | 92f91930172eec04f302898d2957e32f1d773348 (diff) | |
download | outils-879d51525932a2ba2841744ed302c170b5dc8270.tar.gz outils-879d51525932a2ba2841744ed302c170b5dc8270.tar.xz outils-879d51525932a2ba2841744ed302c170b5dc8270.zip |
add liboutils (from OpenBSD, libressl-portable, obase)
Diffstat (limited to 'src/liboutils/ohash.c')
-rw-r--r-- | src/liboutils/ohash.c | 327 |
1 files changed, 327 insertions, 0 deletions
diff --git a/src/liboutils/ohash.c b/src/liboutils/ohash.c new file mode 100644 index 0000000..74ca4fa --- /dev/null +++ b/src/liboutils/ohash.c @@ -0,0 +1,327 @@ +/* $OpenBSD: 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 <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); +} |