src/server/ucx/map.c

/*
 *
 */

#include <stdlib.h>
#include <string.h>

#include "map.h"

UcxMap *ucx_map_new(size_t size) {
    UcxMap *map = (UcxMap*)malloc(sizeof(UcxMap));
    if(map == NULL) {
        return NULL;
    }

    map->map = (UcxMapElement**)calloc(size, sizeof(UcxMapElement*));
    if(map->map == NULL) {
        free(map);
        return NULL;
    }
    map->size = size;

    return map;
}

void ucx_map_free(UcxMap *map) {
    for (size_t n = 0 ; n < map->size ; n++) {
        UcxMapElement *elem = map->map[n];
        if (elem != NULL) {
            do {
                UcxMapElement *next = elem->next;
                free(elem->key.data);
                free(elem);
                elem = next;
            } while (elem != NULL);
        }
    }
    free(map->map);
    free(map);
}

int ucx_map_put(UcxMap *map, UcxKey key, void *data) {
    if(key.hash == 0) {
        key.hash = ucx_hash((char*)key.data, key.len);
    }

    size_t slot = key.hash%map->size;
    UcxMapElement *elm = map->map[slot];
    UcxMapElement *prev = NULL;

    while (elm != NULL && elm->key.hash < key.hash) {
        prev = elm;
        elm = elm->next;
    }
    
    if (elm == NULL || elm->key.hash != key.hash) {
        UcxMapElement *e = (UcxMapElement*)malloc(sizeof(UcxMapElement));
        if(e == NULL) {
            return -1;
        }
        e->key.data = NULL;
        if (prev == NULL) {
            map->map[slot] = e;
        } else {
            prev->next = e;
        }
        e->next = elm;
        elm = e;
    }
    
    if(elm->key.data == NULL) {
        void *kd = malloc(key.len);
        if (kd == NULL) {
            return -1;
        }
        memcpy(kd, key.data, key.len);
        key.data = kd;
        elm->key = key;
    }
    elm->data = data;

    return 0;
}

void* ucx_map_get(UcxMap *map, UcxKey key) {
    if(key.hash == 0) {
        key.hash = ucx_hash((char*)key.data, key.len);
    }
    
    UcxMapElement *elm = map->map[key.hash%map->size];
    while (elm != NULL && elm->key.hash <= key.hash) {
        if(elm->key.hash == key.hash) {
            int n = (key.len > elm->key.len) ? elm->key.len : key.len;
            if (memcmp(elm->key.data, key.data, n) == 0) {
                return elm->data;
            }
        }
        elm = elm->next;
    }

    return NULL;
}

UcxKey ucx_key(void *data, size_t len) {
    UcxKey key;
    key.data = data;
    key.len = len;
    key.hash = ucx_hash(data, len);
    return key;
}


int ucx_hash(char *data, size_t len) {
    /* murmur hash 2 */

    int m = 0x5bd1e995;
    int r = 24;

    int h = 25 ^ len;

    int i = 0;
    while (len >= 4) {
        int k = data[i + 0] & 0xFF;
        k |= (data[i + 1] & 0xFF) << 8;
        k |= (data[i + 2] & 0xFF) << 16;
        k |= (data[i + 3] & 0xFF) << 24;

        k *= m;
        k ^= k >> r;
        k *= m;

        h *= m;
        h ^= k;

        i += 4;
        len -= 4;
    }

    switch (len) {
        case 3: h ^= (data[i + 2] & 0xFF) << 16;
        case 2: h ^= (data[i + 1] & 0xFF) << 8;
        case 1: h ^= (data[i + 0] & 0xFF); h *= m;
    }

    h ^= h >> 13;
    h *= m;
    h ^= h >> 15;

    return h;
}

UcxMapIterator ucx_map_iterator(UcxMap *map) {
    UcxMapIterator i;
    i.map = map;
    i.cur = NULL;
    i.index = 0;
    return i;
}

int ucx_map_iter_next(UcxMapIterator *i, void **elm) {
    UcxMapElement *e = i->cur;
    
    if(e == NULL) {
        e = i->map->map[0];
    } else {
        e = e->next;
    }
    
    while(i->index < i->map->size) {
        if(e != NULL) {
            if(e->data != NULL) {
                i->cur = e;
                *elm = e->data;
                return 0;
            }

            e = e->next;
        } else {
            i->index++;
            
            if(i->index < i->map->size) {
                e = i->map->map[i->index];
            }
        }
    }
    
    return 1;
}