bs_hashmap.c

/**
 * file :	bs_hashmap.c
 * author :	bushaofeng
 * create :	2016-07-05 20:14
 * func : 
 * history:
 */

#include "bs_hashmap.h"

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

#define HMAP_INITIAL_SIZE (256)
#define HMAP_CHAIN_LENGTH (8)

typedef enum _hashmap_use_state {
    hashmap_unused_0 = 0, hashmap_used_1 = 1
} hashmap_use_state;

/* A element to keep keys and values */
typedef struct _hashmap_elem_t {
    char *key; /* pointer to actual key storage */
    hashmap_use_state used; /* unused_0, used_1 */
    void_ptr data; /* pointer to value memory allocated by callee */
} hashmap_elem_t;

/* A hashmap has maximum size and current size, as well as the elems to hold */
typedef struct _hashmap_map_t {
    int table_size;
    int size;
    hashmap_elem_t *elems;
} hashmap_map_t;

/**
 * The implementation here was originally done by Gary S. Brown.
 * I have borrowed the tables directly, and made some minor changes.
 *
 * COPYRIGHT (C) 1986 Gary S. Brown.
 *   You may use this program, or code or tables extracted from it,
 *   as desired without restriction.
 */
static unsigned long crc32_tab[] = { 0x00000000L, 0x77073096L, 0xee0e612cL,
    0x990951baL, 0x076dc419L, 0x706af48fL, 0xe963a535L, 0x9e6495a3L,
    0x0edb8832L, 0x79dcb8a4L, 0xe0d5e91eL, 0x97d2d988L, 0x09b64c2bL,
    0x7eb17cbdL, 0xe7b82d07L, 0x90bf1d91L, 0x1db71064L, 0x6ab020f2L,
    0xf3b97148L, 0x84be41deL, 0x1adad47dL, 0x6ddde4ebL, 0xf4d4b551L,
    0x83d385c7L, 0x136c9856L, 0x646ba8c0L, 0xfd62f97aL, 0x8a65c9ecL,
    0x14015c4fL, 0x63066cd9L, 0xfa0f3d63L, 0x8d080df5L, 0x3b6e20c8L,
    0x4c69105eL, 0xd56041e4L, 0xa2677172L, 0x3c03e4d1L, 0x4b04d447L,
    0xd20d85fdL, 0xa50ab56bL, 0x35b5a8faL, 0x42b2986cL, 0xdbbbc9d6L,
    0xacbcf940L, 0x32d86ce3L, 0x45df5c75L, 0xdcd60dcfL, 0xabd13d59L,
    0x26d930acL, 0x51de003aL, 0xc8d75180L, 0xbfd06116L, 0x21b4f4b5L,
    0x56b3c423L, 0xcfba9599L, 0xb8bda50fL, 0x2802b89eL, 0x5f058808L,
    0xc60cd9b2L, 0xb10be924L, 0x2f6f7c87L, 0x58684c11L, 0xc1611dabL,
    0xb6662d3dL, 0x76dc4190L, 0x01db7106L, 0x98d220bcL, 0xefd5102aL,
    0x71b18589L, 0x06b6b51fL, 0x9fbfe4a5L, 0xe8b8d433L, 0x7807c9a2L,
    0x0f00f934L, 0x9609a88eL, 0xe10e9818L, 0x7f6a0dbbL, 0x086d3d2dL,
    0x91646c97L, 0xe6635c01L, 0x6b6b51f4L, 0x1c6c6162L, 0x856530d8L,
    0xf262004eL, 0x6c0695edL, 0x1b01a57bL, 0x8208f4c1L, 0xf50fc457L,
    0x65b0d9c6L, 0x12b7e950L, 0x8bbeb8eaL, 0xfcb9887cL, 0x62dd1ddfL,
    0x15da2d49L, 0x8cd37cf3L, 0xfbd44c65L, 0x4db26158L, 0x3ab551ceL,
    0xa3bc0074L, 0xd4bb30e2L, 0x4adfa541L, 0x3dd895d7L, 0xa4d1c46dL,
    0xd3d6f4fbL, 0x4369e96aL, 0x346ed9fcL, 0xad678846L, 0xda60b8d0L,
    0x44042d73L, 0x33031de5L, 0xaa0a4c5fL, 0xdd0d7cc9L, 0x5005713cL,
    0x270241aaL, 0xbe0b1010L, 0xc90c2086L, 0x5768b525L, 0x206f85b3L,
    0xb966d409L, 0xce61e49fL, 0x5edef90eL, 0x29d9c998L, 0xb0d09822L,
    0xc7d7a8b4L, 0x59b33d17L, 0x2eb40d81L, 0xb7bd5c3bL, 0xc0ba6cadL,
    0xedb88320L, 0x9abfb3b6L, 0x03b6e20cL, 0x74b1d29aL, 0xead54739L,
    0x9dd277afL, 0x04db2615L, 0x73dc1683L, 0xe3630b12L, 0x94643b84L,
    0x0d6d6a3eL, 0x7a6a5aa8L, 0xe40ecf0bL, 0x9309ff9dL, 0x0a00ae27L,
    0x7d079eb1L, 0xf00f9344L, 0x8708a3d2L, 0x1e01f268L, 0x6906c2feL,
    0xf762575dL, 0x806567cbL, 0x196c3671L, 0x6e6b06e7L, 0xfed41b76L,
    0x89d32be0L, 0x10da7a5aL, 0x67dd4accL, 0xf9b9df6fL, 0x8ebeeff9L,
    0x17b7be43L, 0x60b08ed5L, 0xd6d6a3e8L, 0xa1d1937eL, 0x38d8c2c4L,
    0x4fdff252L, 0xd1bb67f1L, 0xa6bc5767L, 0x3fb506ddL, 0x48b2364bL,
    0xd80d2bdaL, 0xaf0a1b4cL, 0x36034af6L, 0x41047a60L, 0xdf60efc3L,
    0xa867df55L, 0x316e8eefL, 0x4669be79L, 0xcb61b38cL, 0xbc66831aL,
    0x256fd2a0L, 0x5268e236L, 0xcc0c7795L, 0xbb0b4703L, 0x220216b9L,
    0x5505262fL, 0xc5ba3bbeL, 0xb2bd0b28L, 0x2bb45a92L, 0x5cb36a04L,
    0xc2d7ffa7L, 0xb5d0cf31L, 0x2cd99e8bL, 0x5bdeae1dL, 0x9b64c2b0L,
    0xec63f226L, 0x756aa39cL, 0x026d930aL, 0x9c0906a9L, 0xeb0e363fL,
    0x72076785L, 0x05005713L, 0x95bf4a82L, 0xe2b87a14L, 0x7bb12baeL,
    0x0cb61b38L, 0x92d28e9bL, 0xe5d5be0dL, 0x7cdcefb7L, 0x0bdbdf21L,
    0x86d3d2d4L, 0xf1d4e242L, 0x68ddb3f8L, 0x1fda836eL, 0x81be16cdL,
    0xf6b9265bL, 0x6fb077e1L, 0x18b74777L, 0x88085ae6L, 0xff0f6a70L,
    0x66063bcaL, 0x11010b5cL, 0x8f659effL, 0xf862ae69L, 0x616bffd3L,
    0x166ccf45L, 0xa00ae278L, 0xd70dd2eeL, 0x4e048354L, 0x3903b3c2L,
    0xa7672661L, 0xd06016f7L, 0x4969474dL, 0x3e6e77dbL, 0xaed16a4aL,
    0xd9d65adcL, 0x40df0b66L, 0x37d83bf0L, 0xa9bcae53L, 0xdebb9ec5L,
    0x47b2cf7fL, 0x30b5ffe9L, 0xbdbdf21cL, 0xcabac28aL, 0x53b39330L,
    0x24b4a3a6L, 0xbad03605L, 0xcdd70693L, 0x54de5729L, 0x23d967bfL,
    0xb3667a2eL, 0xc4614ab8L, 0x5d681b02L, 0x2a6f2b94L, 0xb40bbe37L,
    0xc30c8ea1L, 0x5a05df1bL, 0x2d02ef8dL };

/**
 * Return a 32-bit CRC of the contents of the buffer.
 */
static unsigned long crc32(const unsigned char *s, unsigned int len) {
    unsigned int i;
    unsigned long crc32val = 0;
    for (i = 0; i < len; i++) {
        crc32val = crc32_tab[(crc32val ^ s[i]) & 0xff] ^ (crc32val >> 8);
    }
    return crc32val;
}

/**
 * Hashing function for a string
 */
static unsigned int _find_hash_index(hashmap_map_t * m, const char* keystring) {
    unsigned long key = crc32(keystring, strlen(keystring));
    
    /* Robert Jenkins' 32 bit Mix Function */
    key += (key << 12);
    key ^= (key >> 22);
    key += (key << 4);
    key ^= (key >> 9);
    key += (key << 10);
    key ^= (key >> 2);
    key += (key << 7);
    key ^= (key >> 12);
    
    /* Knuth's Multiplicative Method */
    key = (key >> 3) * 0x9E3779B1;
    
    return key % m->table_size;
}

/**
 * Return the integer of the location in data to store the point to the item,
 *   or HMAP_E_OVERFLOW.
 */
static int _hashmap_hash(hmap_t in, char* key) {
    int curr;
    int i;
    hashmap_elem_t *elem;
    hashmap_map_t *m = (hashmap_map_t *) in;
    
    /* If full, return immediately */
    if (m->size >= (m->table_size / 2)) {
        return HMAP_E_OVERFLOW;
    }
    
    /* Find the best index */
    curr = _find_hash_index(m, key);
    
    /* Linear probing */
    for (i = 0; i < HMAP_CHAIN_LENGTH; i++) {
        elem = m->elems + curr;
        if (elem->used == hashmap_unused_0) {
            return curr;
        }
        
        if (elem->used == hashmap_used_1 && (!strcmp(elem->key, key))) {
            return curr;
        }
        
        curr = (curr + 1) % m->table_size;
    }
    return HMAP_E_OVERFLOW;
}

/**
 * Doubles the size of the hashmap, and rehashes all the elements
 */
static int _hashmap_rehash(hmap_t in) {
    int i;
    int old_size;
    hashmap_elem_t *curr;
    hashmap_elem_t *elem;
    
    /* Setup the new elements */
    hashmap_map_t *m = (hashmap_map_t *) in;
    hashmap_elem_t *temp = (hashmap_elem_t *) calloc(2 * m->table_size,
                                                     sizeof(hashmap_elem_t));
    if (!temp) {
        return HMAP_E_OUTMEM;
    }
    
    /* Update the array */
    curr = m->elems;
    m->elems = temp;
    
    /* Update the size */
    old_size = m->table_size;
    m->table_size = 2 * m->table_size;
    m->size = 0;
    
    /* Rehash the elements */
    for (i = 0; i < old_size; i++) {
        int status;
        elem = curr + i;
        if (elem->used == hashmap_unused_0) {
            continue;
        }
        status = hashmap_put(m, elem->key, elem->data);
        if (status != HMAP_S_OK) {
            return status;
        }
    }
    
    free(curr);
    return HMAP_S_OK;
}

/**
 * Create an empty hashmap
 */
hmap_t hashmap_create() {
    hashmap_map_t* m = (hashmap_map_t*) malloc(sizeof(hashmap_map_t));
    if (!m) {
        exit(HMAP_E_OUTMEM);
    }
    
    m->elems = (hashmap_elem_t*) calloc(HMAP_INITIAL_SIZE,
                                        sizeof(hashmap_elem_t));
    if (!m->elems) {
        free(m);
        exit(HMAP_E_OUTMEM);
    }
    
    m->table_size = HMAP_INITIAL_SIZE;
    m->size = 0;
    
    return m;
}

/**
 * Add a pair of key-value to the hashmap
 */
int hashmap_put(hmap_t in, char* key, void_ptr value) {
    int index;
    hashmap_map_t *m;
    hashmap_elem_t *elem;
    
    m = (hashmap_map_t *) in;
    
    /* Find a place to put our value */
    index = _hashmap_hash(in, key);
    while (index == HMAP_E_OVERFLOW) {
        if (_hashmap_rehash(in) == HMAP_E_OUTMEM) {
            return HMAP_E_OUTMEM;
        }
        index = _hashmap_hash(in, key);
    }
    
    /* Set the elems */
    elem = m->elems + index;
    if (elem->used == hashmap_used_1) {
        /* Find a repeated key */
        return HMAP_E_KEYUSED;
    }
    elem->data = value;
    elem->key = key; /* only set to a reference */
    elem->used = hashmap_used_1;
    m->size++;
    
    return HMAP_S_OK;
}

/**
 * Get your pointer out of the hashmap with a key
 */
int hashmap_get(hmap_t in, const char* key, void_ptr *value) {
    int curr;
    int i;
    hashmap_map_t *m;
    hashmap_elem_t *elem;
    
    m = (hashmap_map_t *) in;
    
    /* Find element location */
    curr = _find_hash_index(m, key);
    
    /* Linear probing, if necessary */
    for (i = 0; i < HMAP_CHAIN_LENGTH; i++) {
        elem = m->elems + curr;
        if (elem->used == hashmap_used_1) {
            if (!strcmp(elem->key, key)) {
                *value = (elem->data);
                return HMAP_S_OK;
            }
        }
        curr = (curr + 1) % m->table_size;
    }
    
    *value = NULL;
    return HMAP_E_NOTFOUND;
}

/**
 * Iterate the function parameter over each element in the hashmap. The
 * additional void_ptr argument is passed to the function as its first
 * argument and the hashmap element is the second.
 */
int hashmap_iterate(hmap_t in, hmap_callback_func fnIterValue, void_ptr arg) {
    int i;
    hashmap_elem_t *elem;
    hashmap_map_t *m = (hashmap_map_t*) in;
    
    if (hashmap_size(m) <= 0) {
        return HMAP_E_NOTFOUND;
    }
    
    for (i = 0; i < m->table_size; i++) {
        elem = m->elems + i;
        if (elem->used == hashmap_used_1) {
            int status = fnIterValue(elem->data, arg);
            if (status != HMAP_S_OK) {
                return status;
            }
        }
    }
    return HMAP_S_OK;
}

/**
 * Remove an element with that key from the map
 */
int hashmap_remove(hmap_t in, char* key, void_ptr *outValue) {
    int i, curr;
    hashmap_map_t* m;
    hashmap_elem_t *elem;
    
    /* Cast the hashmap */
    m = (hashmap_map_t *) in;
    
    if (outValue) {
        *outValue = NULL;
    }
    
    /* Find key */
    curr = _find_hash_index(m, key);
    
    /* Linear probing, if necessary */
    for (i = 0; i < HMAP_CHAIN_LENGTH; i++) {
        elem = m->elems + curr;
        if (elem->used == hashmap_used_1) {
            if (!strcmp(elem->key, key)) {
                /* Blank out the fields */
                elem->used = hashmap_unused_0;
                elem->key = NULL;
                if (outValue) {
                    *outValue = elem->data;
                }
                elem->data = NULL;
                
                /* Reduce the size */
                m->size--;
                return HMAP_S_OK;
            }
        }
        curr = (curr + 1) % m->table_size;
    }
    /* Data not found */
    return HMAP_E_NOTFOUND;
}

/**
 * Deallocate the hashmap
 */
void hashmap_destroy(hmap_t in, hmap_callback_func fnFreeValue, void_ptr arg) {
    hashmap_elem_t *elem;
    void_ptr data;
    hashmap_map_t* m = (hashmap_map_t*) in;
    
    while (m->table_size-- > 0) {
        elem = m->elems + (m->table_size);
        if (elem->used == hashmap_used_1) {
            elem->used = hashmap_unused_0;
            elem->key = NULL;
            data = elem->data;
            elem->data = NULL;
            
            if (fnFreeValue) {
                fnFreeValue(data, arg);
            }
        }
    }
    
    free(m->elems);
    free(m);
}

/**
 * Return the length of the hashmap
 */
int hashmap_size(hmap_t in) {
    hashmap_map_t* m = (hashmap_map_t *) in;
    if (m) {
        return m->size;
    } else {
        return 0;
    }
}