mbpfan/src/strmap.c

/*
 *    strmap version 2.0.0
 *
 *    ANSI C hash table for strings.
 *
 *	  Version history:
 *	  1.0.0 - initial release
 *	  2.0.0 - changed function prefix from strmap to sm to ensure
 *	      ANSI C compatibility
 *
 *    strmap.c
 *
 *    Copyright (c) 2009, 2011 Per Ola Kristensson.
 *
 *    Per Ola Kristensson <pok21@cam.ac.uk>
 *    Inference Group, Department of Physics
 *    University of Cambridge
 *    Cavendish Laboratory
 *    JJ Thomson Avenue
 *    CB3 0HE Cambridge
 *    United Kingdom
 *
 *    strmap is free software: you can redistribute it and/or modify
 *    it under the terms of the GNU Lesser General Public License as published by
 *    the Free Software Foundation, either version 3 of the License, or
 *    (at your option) any later version.
 *
 *    strmap is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    GNU Lesser General Public License for more details.
 *
 *    You should have received a copy of the GNU Lesser General Public License
 *    along with strmap.  If not, see <http://www.gnu.org/licenses/>.
 */
#include "strmap.h"

typedef struct Pair Pair;

typedef struct Bucket Bucket;

struct Pair {
    char *key;
    char *value;
};

struct Bucket {
    unsigned int count;
    Pair *pairs;
};

struct StrMap {
    unsigned int count;
    Bucket *buckets;
};

static Pair * get_pair(Bucket *bucket, const char *key);
static unsigned long hash(const char *str);

StrMap * sm_new(unsigned int capacity)
{
    StrMap *map;

    map = (StrMap*)malloc(sizeof(StrMap));

    if (map == NULL) {
        return NULL;
    }

    map->count = capacity;
    map->buckets = (Bucket*)malloc(map->count * sizeof(Bucket));

    if (map->buckets == NULL) {
        free(map);
        return NULL;
    }

    memset(map->buckets, 0, map->count * sizeof(Bucket));
    return map;
}

void sm_delete(StrMap *map)
{
    unsigned int i, j, n, m;
    Bucket *bucket;
    Pair *pair;

    if (map == NULL) {
        return;
    }

    n = map->count;
    bucket = map->buckets;
    i = 0;

    while (i < n) {
        m = bucket->count;
        pair = bucket->pairs;
        j = 0;

        while(j < m) {
            free(pair->key);
            free(pair->value);
            pair++;
            j++;
        }

        free(bucket->pairs);
        bucket++;
        i++;
    }

    free(map->buckets);
    free(map);
}

int sm_get(const StrMap *map, const char *key, char *out_buf, unsigned int n_out_buf)
{
    unsigned int index;
    Bucket *bucket;
    Pair *pair;

    if (map == NULL) {
        return 0;
    }

    if (key == NULL) {
        return 0;
    }

    index = hash(key) % map->count;
    bucket = &(map->buckets[index]);
    pair = get_pair(bucket, key);

    if (pair == NULL) {
        return 0;
    }

    if (out_buf == NULL && n_out_buf == 0) {
        return strlen(pair->value) + 1;
    }

    if (out_buf == NULL) {
        return 0;
    }

    if (strlen(pair->value) >= n_out_buf) {
        return 0;
    }

    strcpy(out_buf, pair->value);
    return 1;
}

int sm_exists(const StrMap *map, const char *key)
{
    unsigned int index;
    Bucket *bucket;
    Pair *pair;

    if (map == NULL) {
        return 0;
    }

    if (key == NULL) {
        return 0;
    }

    index = hash(key) % map->count;
    bucket = &(map->buckets[index]);
    pair = get_pair(bucket, key);

    if (pair == NULL) {
        return 0;
    }

    return 1;
}

int sm_put(StrMap *map, const char *key, const char *value)
{
    unsigned int key_len, value_len, index;
    Bucket *bucket;
    Pair *tmp_pairs, *pair;
    char *tmp_value;
    char *new_key, *new_value;

    if (map == NULL) {
        return 0;
    }

    if (key == NULL || value == NULL) {
        return 0;
    }

    key_len = strlen(key);
    value_len = strlen(value);
    /* Get a pointer to the bucket the key string hashes to */
    index = hash(key) % map->count;
    bucket = &(map->buckets[index]);

    /* Check if we can handle insertion by simply replacing
     * an existing value in a key-value pair in the bucket.
     */
    if ((pair = get_pair(bucket, key)) != NULL) {
        /* The bucket contains a pair that matches the provided key,
         * change the value for that pair to the new value.
         */
        if (strlen(pair->value) < value_len) {
            /* If the new value is larger than the old value, re-allocate
             * space for the new larger value.
             */
            tmp_value = (char*)realloc(pair->value, (value_len + 1) * sizeof(char));

            if (tmp_value == NULL) {
                return 0;
            }

            pair->value = tmp_value;
        }

        /* Copy the new value into the pair that matches the key */
        strcpy(pair->value, value);
        return 1;
    }

    /* Allocate space for a new key and value */
    new_key = (char*)malloc((key_len + 1) * sizeof(char));

    if (new_key == NULL) {
        return 0;
    }

    new_value = (char*)malloc((value_len + 1) * sizeof(char));

    if (new_value == NULL) {
        free(new_key);
        return 0;
    }

    /* Create a key-value pair */
    if (bucket->count == 0) {
        /* The bucket is empty, lazily allocate space for a single
         * key-value pair.
         */
        bucket->pairs = (Pair*)malloc(sizeof(Pair));

        if (bucket->pairs == NULL) {
            free(new_key);
            free(new_value);
            return 0;
        }

        bucket->count = 1;

    } else {
        /* The bucket wasn't empty but no pair existed that matches the provided
         * key, so create a new key-value pair.
         */
        tmp_pairs = (Pair*)realloc(bucket->pairs, (bucket->count + 1) * sizeof(Pair));

        if (tmp_pairs == NULL) {
            free(new_key);
            free(new_value);
            return 0;
        }

        bucket->pairs = tmp_pairs;
        bucket->count++;
    }

    /* Get the last pair in the chain for the bucket */
    pair = &(bucket->pairs[bucket->count - 1]);
    pair->key = new_key;
    pair->value = new_value;
    /* Copy the key and its value into the key-value pair */
    strcpy(pair->key, key);
    strcpy(pair->value, value);
    return 1;
}

int sm_get_count(const StrMap *map)
{
    unsigned int i, j, n, m;
    unsigned int count;
    Bucket *bucket;
    Pair *pair;

    if (map == NULL) {
        return 0;
    }

    bucket = map->buckets;
    n = map->count;
    i = 0;
    count = 0;

    while (i < n) {
        pair = bucket->pairs;
        m = bucket->count;
        j = 0;

        while (j < m) {
            count++;
            pair++;
            j++;
        }

        bucket++;
        i++;
    }

    return count;
}

int sm_enum(const StrMap *map, sm_enum_func enum_func, const void *obj)
{
    unsigned int i, j, n, m;
    Bucket *bucket;
    Pair *pair;

    if (map == NULL) {
        return 0;
    }

    if (enum_func == NULL) {
        return 0;
    }

    bucket = map->buckets;
    n = map->count;
    i = 0;

    while (i < n) {
        pair = bucket->pairs;
        m = bucket->count;
        j = 0;

        while (j < m) {
            enum_func(pair->key, pair->value, obj);
            pair++;
            j++;
        }

        bucket++;
        i++;
    }

    return 1;
}

/*
 * Returns a pair from the bucket that matches the provided key,
 * or null if no such pair exist.
 */
static Pair * get_pair(Bucket *bucket, const char *key)
{
    unsigned int i, n;
    Pair *pair;

    n = bucket->count;

    if (n == 0) {
        return NULL;
    }

    pair = bucket->pairs;
    i = 0;

    while (i < n) {
        if (pair->key != NULL && pair->value != NULL) {
            if (strcmp(pair->key, key) == 0) {
                return pair;
            }
        }

        pair++;
        i++;
    }

    return NULL;
}

/*
 * Returns a hash code for the provided string.
 */
static unsigned long hash(const char *str)
{
    unsigned long hash = 5381;
    int c;

    while ((c = *str++)) {
        hash = ((hash << 5) + hash) + c;
    }

    return hash;
}

/*

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*/