symtab.c

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/*
 * Portions Copyright (C) 2004, 2005, 2007  Internet Systems Consortium, Inc. ("ISC")
 * Portions Copyright (C) 2001  Internet Software Consortium.
 *
 * Permission to use, copy, modify, and/or 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 ISC AND NOMINUM DISCLAIMS ALL
 * WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC 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.
 *
 * Portions Copyright (C) 2001  Nominum, Inc.
 *
 * Permission to use, copy, modify, and/or 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 ISC AND NOMINUM DISCLAIMS ALL
 * WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC 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.
 */

/* $Id: symtab.c,v 1.11 2007/09/13 04:45:18 each Exp $ */

/*! \file */

#include <config.h>

#include <ctype.h>
#include <stdlib.h>

#include <isc/assertions.h>
#include <isc/magic.h>
#include <isc/string.h>

#include <isccc/result.h>
#include <isccc/symtab.h>
#include <isccc/util.h>

typedef struct elt {
        char *                          key;
        unsigned int                    type;
        isccc_symvalue_t                        value;
        ISC_LINK(struct elt)            link;
} elt_t;

typedef ISC_LIST(elt_t)                 eltlist_t;

#define SYMTAB_MAGIC                    ISC_MAGIC('S', 'y', 'm', 'T')
#define VALID_SYMTAB(st)                ISC_MAGIC_VALID(st, SYMTAB_MAGIC)

struct isccc_symtab {
        unsigned int                    magic;
        unsigned int                    size;
        eltlist_t *                     table;
        isccc_symtabundefaction_t               undefine_action;
        void *                          undefine_arg;
        isc_boolean_t                   case_sensitive;
};

isc_result_t
isccc_symtab_create(unsigned int size,
                  isccc_symtabundefaction_t undefine_action,
                  void *undefine_arg,
                  isc_boolean_t case_sensitive,
                  isccc_symtab_t **symtabp)
{
        isccc_symtab_t *symtab;
        unsigned int i;

        REQUIRE(symtabp != NULL && *symtabp == NULL);
        REQUIRE(size > 0);      /* Should be prime. */

        symtab = malloc(sizeof(*symtab));
        if (symtab == NULL)
                return (ISC_R_NOMEMORY);
        symtab->table = malloc(size * sizeof(eltlist_t));
        if (symtab->table == NULL) {
                free(symtab);
                return (ISC_R_NOMEMORY);
        }
        for (i = 0; i < size; i++)
                ISC_LIST_INIT(symtab->table[i]);
        symtab->size = size;
        symtab->undefine_action = undefine_action;
        symtab->undefine_arg = undefine_arg;
        symtab->case_sensitive = case_sensitive;
        symtab->magic = SYMTAB_MAGIC;

        *symtabp = symtab;

        return (ISC_R_SUCCESS);
}

static inline void
free_elt(isccc_symtab_t *symtab, unsigned int bucket, elt_t *elt) {
        ISC_LIST_UNLINK(symtab->table[bucket], elt, link);
        if (symtab->undefine_action != NULL)
                (symtab->undefine_action)(elt->key, elt->type, elt->value,
                                          symtab->undefine_arg);
        free(elt);
}

void
isccc_symtab_destroy(isccc_symtab_t **symtabp) {
        isccc_symtab_t *symtab;
        unsigned int i;
        elt_t *elt, *nelt;

        REQUIRE(symtabp != NULL);
        symtab = *symtabp;
        REQUIRE(VALID_SYMTAB(symtab));

        for (i = 0; i < symtab->size; i++) {
                for (elt = ISC_LIST_HEAD(symtab->table[i]);
                     elt != NULL;
                     elt = nelt) {
                        nelt = ISC_LIST_NEXT(elt, link);
                        free_elt(symtab, i, elt);
                }
        }
        free(symtab->table);
        symtab->magic = 0;
        free(symtab);

        *symtabp = NULL;
}

static inline unsigned int
hash(const char *key, isc_boolean_t case_sensitive) {
        const char *s;
        unsigned int h = 0;
        unsigned int g;
        int c;

        /*
         * P. J. Weinberger's hash function, adapted from p. 436 of
         * _Compilers: Principles, Techniques, and Tools_, Aho, Sethi
         * and Ullman, Addison-Wesley, 1986, ISBN 0-201-10088-6.
         */

        if (case_sensitive) {
                for (s = key; *s != '\0'; s++) {
                        h = ( h << 4 ) + *s;
                        if ((g = ( h & 0xf0000000 )) != 0) {
                                h = h ^ (g >> 24);
                                h = h ^ g;
                        }
                }
        } else {
                for (s = key; *s != '\0'; s++) {
                        c = *s;
                        c = tolower((unsigned char)c);
                        h = ( h << 4 ) + c;
                        if ((g = ( h & 0xf0000000 )) != 0) {
                                h = h ^ (g >> 24);
                                h = h ^ g;
                        }
                }
        }

        return (h);
}

#define FIND(s, k, t, b, e) \
        b = hash((k), (s)->case_sensitive) % (s)->size; \
        if ((s)->case_sensitive) { \
                for (e = ISC_LIST_HEAD((s)->table[b]); \
                     e != NULL; \
                     e = ISC_LIST_NEXT(e, link)) { \
                        if (((t) == 0 || e->type == (t)) && \
                            strcmp(e->key, (k)) == 0) \
                                break; \
                } \
        } else { \
                for (e = ISC_LIST_HEAD((s)->table[b]); \
                     e != NULL; \
                     e = ISC_LIST_NEXT(e, link)) { \
                        if (((t) == 0 || e->type == (t)) && \
                            strcasecmp(e->key, (k)) == 0) \
                                break; \
                } \
        }

isc_result_t
isccc_symtab_lookup(isccc_symtab_t *symtab, const char *key, unsigned int type,
                  isccc_symvalue_t *value)
{
        unsigned int bucket;
        elt_t *elt;

        REQUIRE(VALID_SYMTAB(symtab));
        REQUIRE(key != NULL);

        FIND(symtab, key, type, bucket, elt);

        if (elt == NULL)
                return (ISC_R_NOTFOUND);

        if (value != NULL)
                *value = elt->value;

        return (ISC_R_SUCCESS);
}

isc_result_t
isccc_symtab_define(isccc_symtab_t *symtab, char *key, unsigned int type,
                  isccc_symvalue_t value, isccc_symexists_t exists_policy)
{
        unsigned int bucket;
        elt_t *elt;

        REQUIRE(VALID_SYMTAB(symtab));
        REQUIRE(key != NULL);
        REQUIRE(type != 0);

        FIND(symtab, key, type, bucket, elt);

        if (exists_policy != isccc_symexists_add && elt != NULL) {
                if (exists_policy == isccc_symexists_reject)
                        return (ISC_R_EXISTS);
                INSIST(exists_policy == isccc_symexists_replace);
                ISC_LIST_UNLINK(symtab->table[bucket], elt, link);
                if (symtab->undefine_action != NULL)
                        (symtab->undefine_action)(elt->key, elt->type,
                                                  elt->value,
                                                  symtab->undefine_arg);
        } else {
                elt = malloc(sizeof(*elt));
                if (elt == NULL)
                        return (ISC_R_NOMEMORY);
                ISC_LINK_INIT(elt, link);
        }

        elt->key = key;
        elt->type = type;
        elt->value = value;

        /*
         * We prepend so that the most recent definition will be found.
         */
        ISC_LIST_PREPEND(symtab->table[bucket], elt, link);

        return (ISC_R_SUCCESS);
}

isc_result_t
isccc_symtab_undefine(isccc_symtab_t *symtab, const char *key, unsigned int type) {
        unsigned int bucket;
        elt_t *elt;

        REQUIRE(VALID_SYMTAB(symtab));
        REQUIRE(key != NULL);

        FIND(symtab, key, type, bucket, elt);

        if (elt == NULL)
                return (ISC_R_NOTFOUND);

        free_elt(symtab, bucket, elt);

        return (ISC_R_SUCCESS);
}

void
isccc_symtab_foreach(isccc_symtab_t *symtab, isccc_symtabforeachaction_t action,
                   void *arg)
{
        unsigned int i;
        elt_t *elt, *nelt;

        REQUIRE(VALID_SYMTAB(symtab));
        REQUIRE(action != NULL);

        for (i = 0; i < symtab->size; i++) {
                for (elt = ISC_LIST_HEAD(symtab->table[i]);
                     elt != NULL;
                     elt = nelt) {
                        nelt = ISC_LIST_NEXT(elt, link);
                        if ((action)(elt->key, elt->type, elt->value, arg))
                                free_elt(symtab, i, elt);
                }
        }
}

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