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-rw-r--r--lib/libutil/ohash.c328
1 files changed, 328 insertions, 0 deletions
diff --git a/lib/libutil/ohash.c b/lib/libutil/ohash.c
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--- /dev/null
+++ b/lib/libutil/ohash.c
@@ -0,0 +1,328 @@
+/* $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 <sys/cdefs.h>
+#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);
+}
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