ハッシュマップC実装

チョンマイン

ソースコード（Linux版、Windows版）が含まれます。

    hashmap.c

    hashmap.h

MSVCのテストファイルです。

    main.c

以下はソースコードで、元々はgithubにあったものですが、数カ所を書き直し、テストコードも全て書き直しました。メモリリークはありませんので、ご自由にお使いください。

/**
 * hashmap.h
 */
#ifndef _HASHMAP_H_INCLUDED
#define _HASHMAP_H_INCLUDED

#if defined(__cplusplus)
extern "C" {
#endif

#define HMAP_E_KEYUSED (-5) /* Key already existed */
#define HMAP_E_OUTMEM (-4) /* Out of Memory */
#define HMAP_E_NOTFOUND (-3) /* No such element */
#define HMAP_E_OVERFLOW (-2) /* Hashmap is full */
#define HMAP_E_FAIL (-1) /* Hashmap api fail */
#define HMAP_S_OK (0) /* Success */

/**
 ** void_ptr is a pointer. This allows you to put arbitrary structures in the hashmap.
 */
typedef void* void_ptr;

/**
 * hmap_t is a pointer to an internally maintained data structure.
 * Clients of this package do not need to know how hashmaps are
 They see and manipulate only hmap_t's. */ /* Clients of this package do not need to know how hashmaps are represented.
 They see and manipulate only hmap_t's. */
typedef void_ptr hmap_t;

/**
 * hmap_callback_func is a pointer to a function that can take two void_ptr arguments
 * Returns status code.
 */
typedef int (*hmap_callback_func)(void_ptr, void_ptr);

/**
 * prototype for map element type
 */
typedef struct _hmap_pair_t {
  char *key;
  void_ptr data;
} hmap_pair_t;

/**
 * Return an empty hashmap. returns NULL if empty.
 */
extern hmap_t hashmap_create();

/**
 * Iteratively call fn with argument (value, arg) for each element data * in the hashmap.
 * The function returns anything other than HMAP_S_OK 
 The function returns anything other than HMAP_S_OK. * the traversal is terminated. fn must not modify any hashmap functions.
 */
extern int hashmap_iterate(hmap_t in, hmap_callback_func fnIterValue, void_ptr arg);

/**
 * Add an element to the hashmap.
 * Return HMAP_S_OK, HMAP_E_KEYUSED or HMAP_E_OUTMEM.
 */
extern int hashmap_put(hmap_t in, char* key, void_ptr elem);

/**
 * Get an element from the hashmap. return HMAP_S_OK or HMAP_E_NOTFOUND.
 */
extern int hashmap_get(hmap_t in, const char* key, void_ptr *elem);

/**
 * Remove an element from the hashmap. return HMAP_S_OK or HMAP_E_NOTFOUND.
 */
extern int hashmap_remove(hmap_t in, char* key, void_ptr *outValue);

/**
 * Free the hashmap
 */
extern void hashmap_destroy(hmap_t in, hmap_callback_func fnFreeValue, void_ptr arg);

/**
 * Get the current size of a hashmap
 */
extern int hashmap_size(hmap_t in);

#if defined(__cplusplus)
}
#endif

#endif /* _HASHMAP_H_INCLUDED */

/**
 * hashmap.c
 * Generic hash map implementation.
 */
#include "hashmap.h"

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

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

typedef enum _use_state {
  unused_0 = 0,
  used_1 = 1
} use_state;

/* A element to keep keys and values */
typedef struct _hashmap_elem_t{
  char *key; /* pointer to actual key storage */
  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.
 *I have borrowed the tables directly, and made some minor changes.
 * COPYRIGHT (C) 1986 Gary S. Brow
  /* 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 == unused_0) {
      return curr;
    }

    if(elem->used == 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 == 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) { 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 == used_1) {
    /* Find a repeated key */
    return HMAP_E_KEYUSED;
  }
  elem->data = value;
  elem->key = key; /* only set to a reference */
  elem->used = 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 == 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 eleme

/**
 * main.c
 *
 * Detecting memory leaks only for windows .  
 * Place the following snippet where leak to be tested: 
 * #if defined(_CRTDBG_MAP_ALLOC) 
 * _CrtDumpMemoryLeaks(); 
 * #endif 
 */  
#if defined(WIN32) && defined(_DEBUG)  
  #ifndef _CRTDBG_MAP_ALLOC  
    #pragma message( __FILE__": _CRTDBG_MAP_ALLOC defined only for DEBUG on Win32." )   
    #define _CRTDBG_MAP_ALLOC  
    #include<stdlib.h>   
    #include<crtdbg.h>  
  #endif  
#endif  

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

#include "hashmap.h"

typedef struct userelem_t {
  char key[20];
  char *value;
} userelem;

typedef struct userdata_t {
  char name[20];
  hmap_t map; /* userelem map */
} userdata;

static int iter_elem(void* elem, void *arg) {
  userelem *el = (userelem *) elem;
  printf("key=%s; value=%s\n", el->key, el->value);
  return 0;
}

static int free_elem(void* elem, void *arg) {
  userelem *el = (userelem *) elem;
  free(el-> value);
  free(el);
  return 0;
}

static int free_data(void* data, void *arg) {
  userdata *dat = (userdata *) data;
  /* delete the entire submap */
  hashmap_destroy(dat-> map, free_elem, 0);
  free(dat);
  return 0;
}

int main(int argc, char* argv[])
{
  hmap_t map;
  userdata *dat;
  userelem *el;
  int ret, i, j;

  /* create hashmap */
  map = hashmap_create();

  /* insert hashmap element */
  for (i=0; i<100; i++) {
    dat = (userdata *)malloc(sizeof(userdata));

    /* create sub hashmap */
    dat->map = hashmap_create();

    /* insert sub hashmap elements */
    for (j=0; j<10; j++) {
      el = (userelem *)malloc(sizeof(userelem));
      sprintf(el->key, "%d", j);

      el->value = (char*) malloc(30);
      sprintf(el->value, "%d", j+1000);
      ret = hashmap_put(date-> map, el-> key, el);
      assert(ret==HMAP_S_OK);
    }

    sprintf(dat->name, "%d", i);
    ret = hashmap_put(map, dat->name, dat);
    assert(ret==HMAP_S_OK);
  }

  printf("hashmap_size: %d\n", hashmap_size(map));

  /* Remove the specified element: key="10" */
  ret = hashmap_remove(map, "10", &dat);
  assert(ret==HMAP_S_OK);
  printf("hashmap_remove: name=%s. size=%d\n", dat->name, hashmap_size(map));
  hashmap_iterate(dat->map, iter_elem, 0);
  free_data(dat, 0);

  /* Remove the specified element: key="11" */
  ret = hashmap_remove(map, "11", &dat);
  assert(ret==HMAP_S_OK);
  printf("hashmap_remove: name=%s. size=%d\n", dat->name, hashmap_size(map));
  hashmap_iterate(dat->map, iter_elem, 0);
  free_data(dat, 0);

  /* Query element: key="99" */
  ret = hashmap_get(map, "99", &dat);
  assert(ret==HMAP_S_OK);
  printf("hashmap_get: name=%s. size=%d\n", dat->name, hashmap_size(map));
  hashmap_iterate(date->map, iter_elem, 0);

  /* delete the entire map */
  hashmap_destroy(map, free_data, 0);

  _CrtDumpMemoryLeaks();
  return 0;
}

/**
 * main.c
 *
 * Detecting memory leaks only for windows .  
 * Place the following snippet where leak to be tested: 
 * #if defined(_CRTDBG_MAP_ALLOC) 
 * _CrtDumpMemoryLeaks(); 
 * #endif 
 */  
#if defined(WIN32) && defined(_DEBUG)  
  #ifndef _CRTDBG_MAP_ALLOC  
    #pragma message( __FILE__": _CRTDBG_MAP_ALLOC defined only for DEBUG on Win32." )   
    #define _CRTDBG_MAP_ALLOC  
    #include<stdlib.h>   
    #include<crtdbg.h>  
  #endif  
#endif  

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

#include "hashmap.h"

typedef struct userelem_t {
  char key[20];
  char *value;
} userelem;

typedef struct userdata_t {
  char name[20];
  hmap_t map; /* userelem map */
} userdata;

static int iter_elem(void* elem, void *arg) {
  userelem *el = (userelem *) elem;
  printf("key=%s; value=%s\n", el->key, el->value);
  return 0;
}

static int free_elem(void* elem, void *arg) {
  userelem *el = (userelem *) elem;
  free(el-> value);
  free(el);
  return 0;
}

static int free_data(void* data, void *arg) {
  userdata *dat = (userdata *) data;
  /* delete the entire submap */
  hashmap_destroy(dat-> map, free_elem, 0);
  free(dat);
  return 0;
}

int main(int argc, char* argv[])
{
  hmap_t map;
  userdata *dat;
  userelem *el;
  int ret, i, j;

  /* create hashmap */
  map = hashmap_create();

  /* insert hashmap element */
  for (i=0; i<100; i++) {
    dat = (userdata *)malloc(sizeof(userdata));

    /* create sub hashmap */
    dat->map = hashmap_create();

    /* insert sub hashmap elements */
    for (j=0; j<10; j++) {
      el = (userelem *)malloc(sizeof(userelem));
      sprintf(el->key, "%d", j);

      el->value = (char*) malloc(30);
      sprintf(el->value, "%d", j+1000);
      ret = hashmap_put(date-> map, el-> key, el);
      assert(ret==HMAP_S_OK);
    }

    sprintf(dat->name, "%d", i);
    ret = hashmap_put(map, dat->name, dat);
    assert(ret==HMAP_S_OK);
  }

  printf("hashmap_size: %d\n", hashmap_size(map));

  /* Remove the specified element: key="10" */
  ret = hashmap_remove(map, "10", &dat);
  assert(ret==HMAP_S_OK);
  printf("hashmap_remove: name=%s. size=%d\n", dat->name, hashmap_size(map));
  hashmap_iterate(dat->map, iter_elem, 0);
  free_data(dat, 0);

  /* Remove the specified element: key="11" */
  ret = hashmap_remove(map, "11", &dat);
  assert(ret==HMAP_S_OK);
  printf("hashmap_remove: name=%s. size=%d\n", dat->name, hashmap_size(map));
  hashmap_iterate(dat->map, iter_elem, 0);
  free_data(dat, 0);

  /* Query element: key="99" */
  ret = hashmap_get(map, "99", &dat);
  assert(ret==HMAP_S_OK);
  printf("hashmap_get: name=%s. size=%d\n", dat->name, hashmap_size(map));
  hashmap_iterate(date->map, iter_elem, 0);

  /* delete the entire map */
  hashmap_destroy(map, free_data, 0);

  _CrtDumpMemoryLeaks();
  return 0;
}