1  /* Copyright (C) 1995, 2000-2003, 2005-2006, 2023 Free Software Foundation, Inc.
       2  
       3     This program is free software: you can redistribute it and/or modify
       4     it under the terms of the GNU Lesser General Public License as published by
       5     the Free Software Foundation; either version 2.1 of the License, or
       6     (at your option) any later version.
       7  
       8     This program is distributed in the hope that it will be useful,
       9     but WITHOUT ANY WARRANTY; without even the implied warranty of
      10     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      11     GNU Lesser General Public License for more details.
      12  
      13     You should have received a copy of the GNU Lesser General Public License
      14     along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
      15  
      16  #ifndef _HASH_H
      17  #define _HASH_H
      18  
      19  #include "obstack.h"
      20  
      21  #ifdef __cplusplus
      22  extern "C" {
      23  #endif
      24  
      25  struct hash_entry;
      26  
      27  typedef struct hash_table
      28  {
      29    unsigned long int size;   /* Number of allocated entries.  */
      30    unsigned long int filled; /* Number of used entries.  */
      31    struct hash_entry *first; /* Pointer to head of list of entries.  */
      32    struct hash_entry *table; /* Pointer to array of entries.  */
      33    struct obstack mem_pool;  /* Memory pool holding the keys.  */
      34  }
      35  hash_table;
      36  
      37  /* Initialize a hash table.  INIT_SIZE > 1 is the initial number of available
      38     entries.
      39     Return 0 always.  */
      40  extern int hash_init (hash_table *htab, unsigned long int init_size);
      41  
      42  /* Delete a hash table's contents.
      43     Return 0 always.  */
      44  extern int hash_destroy (hash_table *htab);
      45  
      46  /* Look up the value of a key in the given table.
      47     If found, return 0 and set *RESULT to it.  Otherwise return -1.  */
      48  extern int hash_find_entry (hash_table *htab,
      49                              const void *key, size_t keylen,
      50                              void **result);
      51  
      52  /* Try to insert the pair (KEY[0..KEYLEN-1], DATA) in the hash table.
      53     Return non-NULL (more precisely, the address of the KEY inside the table's
      54     memory pool) if successful, or NULL if there is already an entry with the
      55     given key.  */
      56  extern const void * hash_insert_entry (hash_table *htab,
      57                                         const void *key, size_t keylen,
      58                                         void *data);
      59  
      60  /* Insert the pair (KEY[0..KEYLEN-1], DATA) in the hash table.
      61     Return 0.  */
      62  extern int hash_set_value (hash_table *htab,
      63                             const void *key, size_t keylen,
      64                             void *data);
      65  
      66  /* Steps *PTR forward to the next used entry in the given hash table.  *PTR
      67     should be initially set to NULL.  Store information about the next entry
      68     in *KEY, *KEYLEN, *DATA.
      69     Return 0 normally, -1 when the whole hash table has been traversed.  */
      70  extern int hash_iterate (hash_table *htab, void **ptr,
      71                           const void **key, size_t *keylen,
      72                           void **data);
      73  
      74  /* Steps *PTR forward to the next used entry in the given hash table.  *PTR
      75     should be initially set to NULL.  Store information about the next entry
      76     in *KEY, *KEYLEN, *DATAP.  *DATAP is set to point to the storage of the
      77     value; modifying **DATAP will modify the value of the entry.
      78     Return 0 normally, -1 when the whole hash table has been traversed.  */
      79  extern int hash_iterate_modify (hash_table *htab, void **ptr,
      80                                  const void **key, size_t *keylen,
      81                                  void ***datap);
      82  
      83  /* Given SEED > 1, return the smallest odd prime number >= SEED.  */
      84  extern unsigned long int next_prime (unsigned long int seed);
      85  
      86  #ifdef __cplusplus
      87  }
      88  #endif
      89  
      90  #endif /* not _HASH_H */