/* hash - hashing table processing.

   Copyright (C) 1998-1999, 2001, 2003, 2009-2020 Free Software Foundation,

   Inc.

   Written by Jim Meyering <meyering@ascend.com>, 1998.

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

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

   the Free Software Foundation; either version 2.1 of the License, or

   (at your option) any later version.

   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 Lesser General Public License for more details.

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

   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */

/* A generic hash table package.  */

/* Make sure USE_OBSTACK is defined to 1 if you want the allocator to use

   obstacks instead of malloc, and recompile 'hash.c' with same setting.  */

#ifndef HASH_H_

# define HASH_H_

# include <stdio.h>

# include <stdbool.h>

typedef size_t (*Hash_hasher) (const void *, size_t);

typedef bool (*Hash_comparator) (const void *, const void *);

typedef void (*Hash_data_freer) (void *);

typedef bool (*Hash_processor) (void *, void *);

struct hash_tuning

  {

    /* This structure is mainly used for 'hash_initialize', see the block

       documentation of 'hash_reset_tuning' for more complete comments.  */

    float shrink_threshold;     /* ratio of used buckets to trigger a shrink */

    float shrink_factor;        /* ratio of new smaller size to original size */

    float growth_threshold;     /* ratio of used buckets to trigger a growth */

    float growth_factor;        /* ratio of new bigger size to original size */

    bool is_n_buckets;          /* if CANDIDATE really means table size */

  };

typedef struct hash_tuning Hash_tuning;

struct hash_table;

typedef struct hash_table Hash_table;

/* Information and lookup.  */

size_t hash_get_n_buckets (const Hash_table *) _GL_ATTRIBUTE_PURE;

size_t hash_get_n_buckets_used (const Hash_table *) _GL_ATTRIBUTE_PURE;

size_t hash_get_n_entries (const Hash_table *) _GL_ATTRIBUTE_PURE;

size_t hash_get_max_bucket_length (const Hash_table *) _GL_ATTRIBUTE_PURE;

bool hash_table_ok (const Hash_table *) _GL_ATTRIBUTE_PURE;

void hash_print_statistics (const Hash_table *, FILE *);

void *hash_lookup (const Hash_table *, const void *);

/* Walking.  */

void *hash_get_first (const Hash_table *) _GL_ATTRIBUTE_PURE;

void *hash_get_next (const Hash_table *, const void *);

size_t hash_get_entries (const Hash_table *, void **, size_t);

size_t hash_do_for_each (const Hash_table *, Hash_processor, void *);

/* Allocation and clean-up.  */

size_t hash_string (const char *, size_t) _GL_ATTRIBUTE_PURE;

void hash_reset_tuning (Hash_tuning *);

Hash_table *hash_initialize (size_t, const Hash_tuning *,

                             Hash_hasher, Hash_comparator,

                             Hash_data_freer) _GL_ATTRIBUTE_NODISCARD;

Hash_table *hash_xinitialize (size_t, const Hash_tuning *,

                              Hash_hasher, Hash_comparator,

                              Hash_data_freer) _GL_ATTRIBUTE_NODISCARD;

void hash_clear (Hash_table *);

void hash_free (Hash_table *);

/* Insertion and deletion.  */

bool hash_rehash (Hash_table *, size_t) _GL_ATTRIBUTE_NODISCARD;

void *hash_insert (Hash_table *, const void *) _GL_ATTRIBUTE_NODISCARD;

void *hash_xinsert (Hash_table *, const void *);

int hash_insert_if_absent (Hash_table *table, const void *entry,

                           const void **matched_ent);

void *hash_delete (Hash_table *, const void *);

#endif