c语言实行泛型hashmap
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代码出处：A simple string hashmap in C https://github.com/petewarden/c_hashmap
main.c
(main2是官方源代码，main是博主写的代码，实现了String类型及Char类型的存取，看官可以根据以下代码触类旁通，限于博主的c语言
功底有限，此处的实现仅为poc代码，不保证严谨性以及稳定性，如果使用到生产环境请多斟酌，测试，如果你有更完善的代码分享，将感激不尽）
/* * A unit test and example of how to use the simple C hashmap */ #include <stdlib.h> #include <stdio.h> #include <assert.h> #include "hashmap.h" #define KEY_MAX_LENGTH (256) #define KEY_PREFIX ("somekey") #define KEY_COUNT (1024*1024) typedef struct data_struct_s char key_string[KEY_MAX_LENGTH]; int number; data_struct_t; typedef struct data_struct_String char key_string[KEY_MAX_LENGTH]; char str[20]; ds_String; typedef struct data_struct_Char char key_string[KEY_MAX_LENGTH]; char ch; ds_Char; void hashmap_putString(map_t *map, ds_String *string) hashmap_put(map, string->key_string, string); void hashmap_getStringValue(map_t *map, char* key) ds_String *out; hashmap_get(map, key, (void**)(&out)); printf("key:%s, value:%s\\n", out->key_string, out->str); void hashmap_putChar(map_t *map, ds_Char *ch) hashmap_put(map, ch->key_string, ch); void hashmap_getCharValue(map_t *map, char* key) ds_Char *out; hashmap_get(map, key, (void**)(&out)); printf("key:%s, value:%c\\n", out->key_string, out->ch); int main() map_t mymap; mymap = hashmap_new(); ds_String *str; ds_Char *ch; str = malloc(sizeof(ds_String)); ch = malloc(sizeof(ds_Char)); //写入String值 snprintf(str->key_string, KEY_MAX_LENGTH, "%s%d", "str", 1); strcpy(str->str, "hello World"); hashmap_putString(mymap, str); hashmap_getStringValue(mymap, str->key_string); //写入Char ch->ch = ‘A‘; snprintf(ch->key_string, KEY_COUNT, "%s%d", "ch", 1); hashmap_putChar(mymap, ch); hashmap_getCharValue(mymap, ch->key_string); int main2(char* argv, int argc) int index; int error; map_t mymap; char key_string[KEY_MAX_LENGTH]; data_struct_t* value; mymap = hashmap_new(); /* First, populate the hash map with ascending values */ for (index = 0; index<KEY_COUNT; index += 1) /* Store the key string along side the numerical value so we can free it later */ value = malloc(sizeof(data_struct_t)); snprintf(value->key_string, KEY_MAX_LENGTH, "%s%d", KEY_PREFIX, index); value->number = index; error = hashmap_put(mymap, value->key_string, value); assert(error == MAP_OK); /* Now, check all of the expected values are there */ for (index = 0; index<KEY_COUNT; index += 1) snprintf(key_string, KEY_MAX_LENGTH, "%s%d", KEY_PREFIX, index); error = hashmap_get(mymap, key_string, (void**)(&value)); /* Make sure the value was both found and the correct number */ assert(error == MAP_OK); assert(value->number == index); /* Make sure that a value that wasn‘t in the map can‘t be found */ snprintf(key_string, KEY_MAX_LENGTH, "%s%d", KEY_PREFIX, KEY_COUNT); error = hashmap_get(mymap, key_string, (void**)(&value)); /* Make sure the value was not found */ assert(error == MAP_MISSING); /* Free all of the values we allocated and remove them from the map */ for (index = 0; index<KEY_COUNT; index += 1) snprintf(key_string, KEY_MAX_LENGTH, "%s%d", KEY_PREFIX, index); error = hashmap_get(mymap, key_string, (void**)(&value)); assert(error == MAP_OK); error = hashmap_remove(mymap, key_string); assert(error == MAP_OK); free(value); /* Now, destroy the map */ hashmap_free(mymap); return 1;
输出结果
hashmap.h
/* * Generic hashmap manipulation functions * * Originally by Elliot C Back - http://elliottback.com/wp/hashmap-implementation-in-c/ * * Modified by Pete Warden to fix a serious performance problem, support strings as keys * and removed thread synchronization - http://petewarden.typepad.com */ #ifndef __HASHMAP_H__ #define __HASHMAP_H__ #define MAP_MISSING -3 /* No such element */ #define MAP_FULL -2 /* Hashmap is full */ #define MAP_OMEM -1 /* Out of Memory */ #define MAP_OK 0 /* OK */ /* * any_t is a pointer. This allows you to put arbitrary structures in * the hashmap. */ typedef void *any_t; /* * PFany is a pointer to a function that can take two any_t arguments * and return an integer. Returns status code.. */ typedef int (*PFany)(any_t, any_t); /* * map_t is a pointer to an internally maintained data structure. * Clients of this package do not need to know how hashmaps are * represented. They see and manipulate only map_t‘s. */ typedef any_t map_t; /* * Return an empty hashmap. Returns NULL if empty. */ extern map_t hashmap_new(); /* * Iteratively call f with argument (item, data) for * each element data in the hashmap. The function must * return a map status code. If it returns anything other * than MAP_OK the traversal is terminated. f must * not reenter any hashmap functions, or deadlock may arise. */ extern int hashmap_iterate(map_t in, PFany f, any_t item); /* * Add an element to the hashmap. Return MAP_OK or MAP_OMEM. */ extern int hashmap_put(map_t in, char* key, any_t value); /* * Get an element from the hashmap. Return MAP_OK or MAP_MISSING. */ extern int hashmap_get(map_t in, char* key, any_t *arg); /* * Remove an element from the hashmap. Return MAP_OK or MAP_MISSING. */ extern int hashmap_remove(map_t in, char* key); /* * Get any element. Return MAP_OK or MAP_MISSING. * remove - should the element be removed from the hashmap */ extern int hashmap_get_one(map_t in, any_t *arg, int remove); /* * Free the hashmap */ extern void hashmap_free(map_t in); /* * Get the current size of a hashmap */ extern int hashmap_length(map_t in); #endif __HASHMAP_H__
hashmap.c
/* * Generic map implementation. */ #include "hashmap.h" #include <stdlib.h> #include <stdio.h> #include <string.h> #define INITIAL_SIZE (256) #define MAX_CHAIN_LENGTH (8) /* We need to keep keys and values */ typedef struct _hashmap_element char* key; int in_use; any_t data; hashmap_element; /* A hashmap has some maximum size and current size, * as well as the data to hold. */ typedef struct _hashmap_map int table_size; int size; hashmap_element *data; hashmap_map; /* * Return an empty hashmap, or NULL on failure. */ map_t hashmap_new() hashmap_map* m = (hashmap_map*) malloc(sizeof(hashmap_map)); if(!m) goto err; m->data = (hashmap_element*) calloc(INITIAL_SIZE, sizeof(hashmap_element)); if(!m->data) goto err; m->table_size = INITIAL_SIZE; m->size = 0; return m; err: if (m) hashmap_free(m); return NULL; /* The implementation here was originally done by Gary S. Brown. I have borrowed the tables directly, and made some minor changes to the crc32-function (including changing the interface). //ylo */ /* ============================================================= */ /* COPYRIGHT (C) 1986 Gary S. Brown. You may use this program, or */ /* code or tables extracted from it, as desired without restriction. */ /* */ /* First, the polynomial itself and its table of feedback terms. The */ /* polynomial is */ /* X^32+X^26+X^23+X^22+X^16+X^12+X^11+X^10+X^8+X^7+X^5+X^4+X^2+X^1+X^0 */ /* */ /* Note that we take it "backwards" and put the highest-order term in */ /* the lowest-order bit. The X^32 term is "implied"; the LSB is the */ /* X^31 term, etc. The X^0 term (usually shown as "+1") results in */ /* the MSB being 1. */ /* */ /* Note that the usual hardware shift register implementation, which */ /* is what we‘re using (we‘re merely optimizing it by doing eight-bit */ /* chunks at a time) shifts bits into the lowest-order term. In our */ /* implementation, that means shifting towards the right. Why do we */ /* do it this way? Because the calculated CRC must be transmitted in */ /* order from highest-order term to lowest-order term. UARTs transmit */ /* characters in order from LSB to MSB. By storing the CRC this way, */ /* we hand it to the UART in the order low-byte to high-byte; the UART */ /* sends each low-bit to hight-bit; and the result is transmission bit */ /* by bit from highest- to lowest-order term without requiring any bit */ /* shuffling on our part. Reception works similarly. */ /* */ /* The feedback terms table consists of 256, 32-bit entries. Notes: */ /* */ /* The table can be generated at runtime if desired; code to do so */ /* is shown later. It might not be obvious, but the feedback */ /* terms simply represent the results of eight shift/xor opera- */ /* tions for all combinations of data and CRC register values. */ /* */ /* The values must be right-shifted by eight bits by the "updcrc" */ /* logic; the shift must be unsigned (bring in zeroes). On some */ /* hardware you could probably optimize the shift in assembler by */ /* using byte-swap instructions. */ /* polynomial $edb88320 */ /* */ /* -------------------------------------------------------------------- */ 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. */ unsigned long crc32(const unsigned char *s, unsigned int len) unsigned int i; unsigned long crc32val; crc32val = 0; for (i = 0; i < len; i ++) crc32val = crc32_tab[(crc32val ^ s[i]) & 0xff] ^ (crc32val >> 8); return crc32val; /* * Hashing function for a string */ unsigned int hashmap_hash_int(hashmap_map * m, char* keystring) unsigned long key = crc32((unsigned char*)(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) * 2654435761; return key % m->table_size; /* * Return the integer of the location in data * to store the point to the item, or MAP_FULL. */ int hashmap_hash(map_t in, char* key) int curr; int i; /* Cast the hashmap */ hashmap_map* m = (hashmap_map *) in; /* If full, return immediately */ if(m->size >= (m->table_size/2)) return MAP_FULL; /* Find the best index */ curr = hashmap_hash_int(m, key); /* Linear probing */ for(i = 0; i< MAX_CHAIN_LENGTH; i++) if(m->data[curr].in_use == 0) return curr; if(m->data[curr].in_use == 1 && (strcmp(m->data[curr].key,key)==0)) return curr; curr = (curr + 1) % m->table_size; return MAP_FULL; /* * Doubles the size of the hashmap, and rehashes all the elements */ int hashmap_rehash(map_t in) int i; int old_size; hashmap_element* curr; /* Setup the new elements */ hashmap_map *m = (hashmap_map *) in; hashmap_element* temp = (hashmap_element *) calloc(2 * m->table_size, sizeof(hashmap_element)); if(!temp) return MAP_OMEM; /* Update the array */ curr = m->data; m->data = 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; if (curr[i].in_use == 0) continue; status = hashmap_put(m, curr[i].key, curr[i].data); if (status != MAP_OK) return status; free(curr); return MAP_OK; /* * Add a pointer to the hashmap with some key */ int hashmap_put(map_t in, char* key, any_t value) int index; hashmap_map* m; /* Cast the hashmap */ m = (hashmap_map *) in; /* Find a place to put our value */ index = hashmap_hash(in, key); while(index == MAP_FULL) if (hashmap_rehash(in) == MAP_OMEM) return MAP_OMEM; index = hashmap_hash(in, key); /* Set the data */ m->data[index].data = value; m->data[index].key = key; m->data[index].in_use = 1; m->size++; return MAP_OK; /* * Get your pointer out of the hashmap with a key */ int hashmap_get(map_t in, char* key, any_t *arg) int curr; int i; hashmap_map* m; /* Cast the hashmap */ m = (hashmap_map *) in; /* Find data location */ curr = hashmap_hash_int(m, key); /* Linear probing, if necessary */ for(i = 0; i<MAX_CHAIN_LENGTH; i++) int in_use = m->data[curr].in_use; if (in_use == 1) if (strcmp(m->data[curr].key,key)==0) *arg = (m->data[curr].data); return MAP_OK; curr = (curr + 1) % m->table_size; *arg = NULL; /* Not found */ return MAP_MISSING; /* * Iterate the function parameter over each element in the hashmap. The * additional any_t argument is passed to the function as its first * argument and the hashmap element is the second. */ int hashmap_iterate(map_t in, PFany f, any_t item) int i; /* Cast the hashmap */ hashmap_map* m = (hashmap_map*) in; /* On empty hashmap, return immediately */ if (hashmap_length(m) <= 0) return MAP_MISSING; /* Linear probing */ for(i = 0; i< m->table_size; i++) if(m->data[i].in_use != 0) any_t data = (any_t) (m->data[i].data); int status = f(item, data); if (status != MAP_OK) return status; return MAP_OK; /* * Remove an element with that key from the map */ int hashmap_remove(map_t in, char* key) int i; int curr; hashmap_map* m; /* Cast the hashmap */ m = (hashmap_map *) in; /* Find key */ curr = hashmap_hash_int(m, key); /* Linear probing, if necessary */ for(i = 0; i<MAX_CHAIN_LENGTH; i++) int in_use = m->data[curr].in_use; if (in_use == 1) if (strcmp(m->data[curr].key,key)==0) /* Blank out the fields */ m->data[curr].in_use = 0; m->data[curr].data = NULL; m->data[curr].key = NULL; /* Reduce the size */ m->size--; return MAP_OK; curr = (curr + 1) % m->table_size; /* Data not found */ return MAP_MISSING; /* Deallocate the hashmap */ void hashmap_free(map_t in) hashmap_map* m = (hashmap_map*) in; free(m->data); free(m); /* Return the length of the hashmap */ int hashmap_length(map_t in) hashmap_map* m = (hashmap_map *) in; if(m != NULL) return m->size; else return 0;
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