/*
 * Copyright (c) 2019 TAOS Data, Inc. <jhtao@taosdata.com>
 *
 * This program is free software: you can use, redistribute, and/or modify
 * it under the terms of the GNU Affero General Public License, version 3
 * or later ("AGPL"), as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */

#ifndef TDENGINE_TSIMPLEHASH_H
#define TDENGINE_TSIMPLEHASH_H

#include "tarray.h"

#ifdef __cplusplus
extern "C" {
#endif

typedef uint32_t (*_hash_fn_t)(const char *, uint32_t);
typedef int32_t (*_equal_fn_t)(const void *, const void *, size_t len);
typedef void (*_hash_free_fn_t)(void *);

/**
 * @brief single thread hash
 *
 */
typedef struct SSHashObj SSHashObj;

/**
 * init the hash table
 *
 * @param capacity    initial capacity of the hash table
 * @param fn          hash function to generate the hash value
 * @return
 */
SSHashObj *tSimpleHashInit(size_t capacity, _hash_fn_t fn);

/**
 * return the size of hash table
 * @param pHashObj
 * @return
 */
int32_t tSimpleHashGetSize(const SSHashObj *pHashObj);

int32_t tSimpleHashPrint(const SSHashObj *pHashObj);

/**
 * @brief put element into hash table, if the element with the same key exists, update it
 *
 * @param pHashObj
 * @param key
 * @param keyLen
 * @param data
 * @param dataLen
 * @return int32_t
 */
int32_t tSimpleHashPut(SSHashObj *pHashObj, const void *key, size_t keyLen, const void *data, size_t dataLen);

/**
 * return the payload data with the specified key
 *
 * @param pHashObj
 * @param key
 * @param keyLen
 * @return
 */
void *tSimpleHashGet(SSHashObj *pHashObj, const void *key, size_t keyLen);

/**
 * remove item with the specified key
 * @param pHashObj
 * @param key
 * @param keyLen
 */
int32_t tSimpleHashRemove(SSHashObj *pHashObj, const void *key, size_t keyLen);

/**
 * remove item with the specified key during hash iterate
 *
 * @param pHashObj
 * @param key
 * @param keyLen
 * @param pIter
 * @param iter
 * @return int32_t
 */
int32_t tSimpleHashIterateRemove(SSHashObj *pHashObj, const void *key, size_t keyLen, void **pIter, int32_t *iter);

/**
 * Clear the hash table.
 * @param pHashObj
 */
void tSimpleHashClear(SSHashObj *pHashObj);

/**
 * Clean up hash table and release all allocated resources.
 * @param handle
 */
void tSimpleHashCleanup(SSHashObj *pHashObj);

/**
 * Get the hash table size
 * @param pHashObj
 * @return
 */
size_t tSimpleHashGetMemSize(const SSHashObj *pHashObj);

#pragma pack(push, 4)
typedef struct SHNode {
  struct SHNode *next;
  uint32_t       keyLen : 20;
  uint32_t       dataLen : 12;
  uint32_t       hashVal;
  char           data[];
} SHNode;
#pragma pack(pop)

/**
 * Get the corresponding key information for a given data in hash table
 * @param data
 * @param keyLen
 * @return
 */
static FORCE_INLINE void *tSimpleHashGetKey(void *data, size_t *keyLen) {
  SHNode *node = (SHNode *)((char *)data - offsetof(SHNode, data));
  if (keyLen) *keyLen = node->keyLen;

  return POINTER_SHIFT(data, node->dataLen);
}

/**
 * Create the hash table iterator
 * @param pHashObj
 * @param data
 * @param iter
 * @return void*
 */
void *tSimpleHashIterate(const SSHashObj *pHashObj, void *data, int32_t *iter);

#ifdef __cplusplus
}
#endif
#endif  // TDENGINE_TSIMPLEHASH_H