#ifndef H_HASH
#define H_HASH

/** \file lib/hash.h
 * Hash table implemenation
 */

typedef struct hashTable_s * hashTable;

#ifdef __cplusplus
extern "C" {
#endif

/** */
typedef unsigned int (*hashFunctionType) (const void * string);
/** */
typedef int (*hashEqualityType) (const void * key1, const void * key2);

/**
 * Return hash value of a string
 * @param string  string on which to calculate hash value
 * @return hash value
 */
unsigned int hashFunctionString(const void * string);

/**
 * Compare two hash table entries for equality.
 * @param key1          entry 1
 * @param key2          entry 2
 * @return 0 if entries are equal
 */
int hashEqualityString(const void * key1, const void * key2);

/**
 * Create hash table.
 * If keySize > 0, the key is duplicated within the table (which costs
 * memory, but may be useful anyway.
 * @param numBuckets    number of hash buckets
 * @param keySize       size of key (0 if unknown)
 * @param freeData      should data be freed when table is destroyed?
 * @param fn            function to generate hash value for key
 * @param eq            function to compare hash keys for equality
 * @return pointer to initialized hash table
 */
hashTable htCreate(int numBuckets, int keySize, int freeData,
		hashFunctionType fn, hashEqualityType eq); 

/**
 * Destroy hash table.
 * @param ht            pointer to hash table
 */
void htFree( /*@only@*/ hashTable ht);

/**
 * Add item to hash table.
 * @param ht            pointer to hash table
 * @param key           pointer to key
 * @param data          pointer to data value
 */
void htAddEntry(hashTable ht, /*@owned@*/ const void * key, /*@owned@*/ const void * data);

/**
 * Retrieve item from hash table.
 * @param ht            pointer to hash table
 * @param key           pointer to key value
 * @retval data         address to store data value from bucket
 * @retval dataCount    address to store data value size from bucket
 * @retval tableKey     address to store key value from bucket (may be NULL)
 * @return 0 on success, 1 if the item is not found.
 */
int htGetEntry(hashTable ht, const void * key, /*@out@*/ const void *** data,
		/*@out@*/ int * dataCount, /*@out@*/const void ** tableKey);

/**
 * Check for key in hash table.
 * @param ht            pointer to hash table
 * @param key           pointer to key value
 * @return 1 if the key is present, 0 otherwise
 */
int htHasEntry(hashTable ht, const void * key);

#ifdef __cplusplus
}
#endif

#endif