hashMap.h

/**
 * 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
 * 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
 * and return an integer. 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 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 */