~drizzle-trunk/drizzle/development

/* -*- mode: c++; c-basic-offset: 2; indent-tabs-mode: nil; -*-

 *  vim:expandtab:shiftwidth=2:tabstop=2:smarttab:

 *

 *  Copyright (C) 2008 Sun Microsystems, Inc.

 *

 *  This program is free software; you can redistribute it and/or modify

 *  it under the terms of the GNU General Public License as published by

 *  the Free Software Foundation; version 2 of the License.

 *

 *  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.  See the

 *  GNU General Public License for more details.

 *

 *  You should have received a copy of the GNU General Public License

 *  along with this program; if not, write to the Free Software

 *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

 */

/* Dynamic hashing of record with different key-length */

#pragma once

#include <drizzled/dynamic_array.h>

namespace drizzled {

/*

  Overhead to store an element in hash

  Can be used to approximate memory consumption for a hash

 */

#define HASH_OVERHEAD (sizeof(char*)*2)

/* flags for hash_init */

#define HASH_UNIQUE     1       /* hash_insert fails on duplicate key */

typedef unsigned char *(*hash_get_key)(const unsigned char *,size_t*,bool);

typedef void (*hash_free_key)(void *);

struct HASH_LINK 

{

  /* index to next key */

  uint32_t next;

  /* data for current entry */

  unsigned char *data;

} ;

struct charset_info_st;

struct HASH

{

  // typedef std::vector<HASH_LINK> array_t;

  typedef DYNAMIC_ARRAY array_t;

  /* Length of key if const length */

  size_t key_offset,key_length;

  uint32_t blength;

  uint32_t records;

  uint32_t flags;

  /* Place for hash_keys */

  array_t array;

  hash_get_key get_key;

  hash_free_key free;

  const charset_info_st *charset;

};

/* A search iterator state */

typedef uint32_t HASH_SEARCH_STATE;

void

_hash_init(HASH *hash,uint32_t growth_size, const charset_info_st* const,

           uint32_t size, size_t key_offset, size_t key_length,

           hash_get_key get_key,

           hash_free_key free_element, uint32_t flags);

#define hash_init(A,B,C,D,E,F,G,H) _hash_init(A,0,B,C,D,E,F,G,H)

void hash_free(HASH *tree);

unsigned char *hash_search(const HASH *info, const unsigned char *key,

                           size_t length);

unsigned char *hash_first(const HASH *info, const unsigned char *key, size_t length, HASH_SEARCH_STATE *state);

bool my_hash_insert(HASH *info,const unsigned char *data);

bool hash_delete(HASH *hash,unsigned char *record);

} /* namespace drizzled */