/* $NetBSD: hash.c,v 1.1.1.2 2009/12/02 00:26:11 haad Exp $ */ /* * Copyright (C) 2001-2004 Sistina Software, Inc. All rights reserved. * Copyright (C) 2004-2007 Red Hat, Inc. All rights reserved. * * This file is part of the device-mapper userspace tools. * * This copyrighted material is made available to anyone wishing to use, * modify, copy, or redistribute it subject to the terms and conditions * of the GNU Lesser General Public License v.2.1. * * You should have received a copy of the GNU Lesser General Public License * along with this program; if not, write to the Free Software Foundation, * Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #include "dmlib.h" struct dm_hash_node { struct dm_hash_node *next; void *data; unsigned keylen; char key[0]; }; struct dm_hash_table { unsigned num_nodes; unsigned num_slots; struct dm_hash_node **slots; }; /* Permutation of the Integers 0 through 255 */ static unsigned char _nums[] = { 1, 14, 110, 25, 97, 174, 132, 119, 138, 170, 125, 118, 27, 233, 140, 51, 87, 197, 177, 107, 234, 169, 56, 68, 30, 7, 173, 73, 188, 40, 36, 65, 49, 213, 104, 190, 57, 211, 148, 223, 48, 115, 15, 2, 67, 186, 210, 28, 12, 181, 103, 70, 22, 58, 75, 78, 183, 167, 238, 157, 124, 147, 172, 144, 176, 161, 141, 86, 60, 66, 128, 83, 156, 241, 79, 46, 168, 198, 41, 254, 178, 85, 253, 237, 250, 154, 133, 88, 35, 206, 95, 116, 252, 192, 54, 221, 102, 218, 255, 240, 82, 106, 158, 201, 61, 3, 89, 9, 42, 155, 159, 93, 166, 80, 50, 34, 175, 195, 100, 99, 26, 150, 16, 145, 4, 33, 8, 189, 121, 64, 77, 72, 208, 245, 130, 122, 143, 55, 105, 134, 29, 164, 185, 194, 193, 239, 101, 242, 5, 171, 126, 11, 74, 59, 137, 228, 108, 191, 232, 139, 6, 24, 81, 20, 127, 17, 91, 92, 251, 151, 225, 207, 21, 98, 113, 112, 84, 226, 18, 214, 199, 187, 13, 32, 94, 220, 224, 212, 247, 204, 196, 43, 249, 236, 45, 244, 111, 182, 153, 136, 129, 90, 217, 202, 19, 165, 231, 71, 230, 142, 96, 227, 62, 179, 246, 114, 162, 53, 160, 215, 205, 180, 47, 109, 44, 38, 31, 149, 135, 0, 216, 52, 63, 23, 37, 69, 39, 117, 146, 184, 163, 200, 222, 235, 248, 243, 219, 10, 152, 131, 123, 229, 203, 76, 120, 209 }; static struct dm_hash_node *_create_node(const char *str, unsigned len) { struct dm_hash_node *n = dm_malloc(sizeof(*n) + len); if (n) { memcpy(n->key, str, len); n->keylen = len; } return n; } static unsigned long _hash(const char *str, unsigned len) { unsigned long h = 0, g; unsigned i; for (i = 0; i < len; i++) { h <<= 4; h += _nums[(unsigned char) *str++]; g = h & ((unsigned long) 0xf << 16u); if (g) { h ^= g >> 16u; h ^= g >> 5u; } } return h; } struct dm_hash_table *dm_hash_create(unsigned size_hint) { size_t len; unsigned new_size = 16u; struct dm_hash_table *hc = dm_malloc(sizeof(*hc)); if (!hc) { stack; return 0; } memset(hc, 0, sizeof(*hc)); /* round size hint up to a power of two */ while (new_size < size_hint) new_size = new_size << 1; hc->num_slots = new_size; len = sizeof(*(hc->slots)) * new_size; if (!(hc->slots = dm_malloc(len))) { stack; goto bad; } memset(hc->slots, 0, len); return hc; bad: dm_free(hc->slots); dm_free(hc); return 0; } static void _free_nodes(struct dm_hash_table *t) { struct dm_hash_node *c, *n; unsigned i; for (i = 0; i < t->num_slots; i++) for (c = t->slots[i]; c; c = n) { n = c->next; dm_free(c); } } void dm_hash_destroy(struct dm_hash_table *t) { _free_nodes(t); dm_free(t->slots); dm_free(t); } static struct dm_hash_node **_find(struct dm_hash_table *t, const char *key, uint32_t len) { unsigned h = _hash(key, len) & (t->num_slots - 1); struct dm_hash_node **c; for (c = &t->slots[h]; *c; c = &((*c)->next)) { if ((*c)->keylen != len) continue; if (!memcmp(key, (*c)->key, len)) break; } return c; } void *dm_hash_lookup_binary(struct dm_hash_table *t, const char *key, uint32_t len) { struct dm_hash_node **c = _find(t, key, len); return *c ? (*c)->data : 0; } int dm_hash_insert_binary(struct dm_hash_table *t, const char *key, uint32_t len, void *data) { struct dm_hash_node **c = _find(t, key, len); if (*c) (*c)->data = data; else { struct dm_hash_node *n = _create_node(key, len); if (!n) return 0; n->data = data; n->next = 0; *c = n; t->num_nodes++; } return 1; } void dm_hash_remove_binary(struct dm_hash_table *t, const char *key, uint32_t len) { struct dm_hash_node **c = _find(t, key, len); if (*c) { struct dm_hash_node *old = *c; *c = (*c)->next; dm_free(old); t->num_nodes--; } } void *dm_hash_lookup(struct dm_hash_table *t, const char *key) { return dm_hash_lookup_binary(t, key, strlen(key) + 1); } int dm_hash_insert(struct dm_hash_table *t, const char *key, void *data) { return dm_hash_insert_binary(t, key, strlen(key) + 1, data); } void dm_hash_remove(struct dm_hash_table *t, const char *key) { dm_hash_remove_binary(t, key, strlen(key) + 1); } unsigned dm_hash_get_num_entries(struct dm_hash_table *t) { return t->num_nodes; } void dm_hash_iter(struct dm_hash_table *t, dm_hash_iterate_fn f) { struct dm_hash_node *c, *n; unsigned i; for (i = 0; i < t->num_slots; i++) for (c = t->slots[i]; c; c = n) { n = c->next; f(c->data); } } void dm_hash_wipe(struct dm_hash_table *t) { _free_nodes(t); memset(t->slots, 0, sizeof(struct dm_hash_node *) * t->num_slots); t->num_nodes = 0u; } char *dm_hash_get_key(struct dm_hash_table *t __attribute((unused)), struct dm_hash_node *n) { return n->key; } void *dm_hash_get_data(struct dm_hash_table *t __attribute((unused)), struct dm_hash_node *n) { return n->data; } static struct dm_hash_node *_next_slot(struct dm_hash_table *t, unsigned s) { struct dm_hash_node *c = NULL; unsigned i; for (i = s; i < t->num_slots && !c; i++) c = t->slots[i]; return c; } struct dm_hash_node *dm_hash_get_first(struct dm_hash_table *t) { return _next_slot(t, 0); } struct dm_hash_node *dm_hash_get_next(struct dm_hash_table *t, struct dm_hash_node *n) { unsigned h = _hash(n->key, n->keylen) & (t->num_slots - 1); return n->next ? n->next : _next_slot(t, h + 1); }