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Annotation of src/usr.bin/cvs/hash.c, Revision 1.1

1.1     ! joris       1: /*     $OpenBSD$       */
        !             2: /*
        !             3:  * Copyright (c) 2008 Joris Vink <joris@openbsd.org>
        !             4:  *
        !             5:  * Permission to use, copy, modify, and distribute this software for any
        !             6:  * purpose with or without fee is hereby granted, provided that the above
        !             7:  * copyright notice and this permission notice appear in all copies.
        !             8:  *
        !             9:  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
        !            10:  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
        !            11:  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
        !            12:  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
        !            13:  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
        !            14:  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
        !            15:  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
        !            16:  */
        !            17:
        !            18: #include <sys/param.h>
        !            19: #include <sys/queue.h>
        !            20:
        !            21: #include <stdio.h>
        !            22: #include <stdlib.h>
        !            23: #include <string.h>
        !            24:
        !            25: #include "cvs.h"
        !            26: #include "hash.h"
        !            27: #include "xmalloc.h"
        !            28:
        !            29: void
        !            30: hash_table_init(struct hash_table *htable, size_t hsize)
        !            31: {
        !            32:        size_t i;
        !            33:        u_int power;
        !            34:
        !            35:        if (hsize < MIN_HASH_SIZE)
        !            36:                hsize = MIN_HASH_SIZE;
        !            37:
        !            38:        if (hsize > MAX_HASH_SIZE)
        !            39:                hsize = MAX_HASH_SIZE;
        !            40:
        !            41:        if ((hsize & (hsize - 1)) != 0) {
        !            42:                for (power = 0; hsize != 0; power++)
        !            43:                        hsize >>= 1;
        !            44:                hsize = 1 << power;
        !            45:        }
        !            46:
        !            47:        htable->h_table = xcalloc(hsize, sizeof(struct hash_head *));
        !            48:        htable->h_size = hsize;
        !            49:
        !            50:        for (i = 0; i < htable->h_size; i++)
        !            51:                SLIST_INIT(&(htable->h_table[i]));
        !            52: }
        !            53:
        !            54: void
        !            55: hash_table_enter(struct hash_table *htable, struct hash_data *e)
        !            56: {
        !            57:        uint32_t hashv;
        !            58:        struct hash_head *tableh;
        !            59:        struct hash_table_entry *entry;
        !            60:
        !            61:        hashv = hash4(e->h_key, strlen(e->h_key));
        !            62:        tableh = &(htable->h_table[(hashv & (htable->h_size - 1))]);
        !            63:
        !            64:        entry = xmalloc(sizeof(*entry));
        !            65:        entry->h_data.h_key = e->h_key;
        !            66:        entry->h_data.h_data = e->h_data;
        !            67:        SLIST_INSERT_HEAD(tableh, entry, h_list);
        !            68: }
        !            69:
        !            70: struct hash_data *
        !            71: hash_table_find(struct hash_table *htable, const char *key, size_t len)
        !            72: {
        !            73:        uint32_t hashv;
        !            74:        struct hash_head *tableh;
        !            75:        struct hash_table_entry *entry;
        !            76:
        !            77:        hashv = hash4(key, len);
        !            78:        tableh = &(htable->h_table[(hashv & (htable->h_size - 1))]);
        !            79:
        !            80:        SLIST_FOREACH(entry, tableh, h_list) {
        !            81:                if (!strcmp(entry->h_data.h_key, key))
        !            82:                        return (&(entry->h_data));
        !            83:        }
        !            84:
        !            85:        return (NULL);
        !            86: }