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hash.h revision 1.1.1.1 
      1 /* Copyright (C) 1995, 2000-2003, 2005-2006 Free Software Foundation, Inc.
      2 
      3    The GNU C Library is free software; you can redistribute it and/or
      4    modify it under the terms of the GNU Library General Public License as
      5    published by the Free Software Foundation; either version 2 of the
      6    License, or (at your option) any later version.
      7 
      8    The GNU C Library 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 GNU
     11    Library General Public License for more details.
     12 
     13    You should have received a copy of the GNU Library General Public
     14    License along with the GNU C Library; see the file COPYING.LIB.  If
     15    not, write to the Free Software Foundation, Inc., 51 Franklin Street,
     16    Fifth Floor, Boston, MA 02110-1301, USA.  */
     17 
     18 #ifndef _HASH_H
     19 #define _HASH_H
     20 
     21 #include "obstack.h"
     22 
     23 #ifdef __cplusplus
     24 extern "C" {
     25 #endif
     26 
     27 struct hash_entry;
     28 
     29 typedef struct hash_table
     30 {
     31   unsigned long int size;   /* Number of allocated entries.  */
     32   unsigned long int filled; /* Number of used entries.  */
     33   struct hash_entry *first; /* Pointer to head of list of entries.  */
     34   struct hash_entry *table; /* Pointer to array of entries.  */
     35   struct obstack mem_pool;  /* Memory pool holding the keys.  */
     36 }
     37 hash_table;
     38 
     39 /* Initialize a hash table.  INIT_SIZE > 1 is the initial number of available
     40    entries.
     41    Return 0 upon successful completion, -1 upon memory allocation error.  */
     42 extern int hash_init (hash_table *htab, unsigned long int init_size);
     43 
     44 /* Delete a hash table's contents.
     45    Return 0 always.  */
     46 extern int hash_destroy (hash_table *htab);
     47 
     48 /* Look up the value of a key in the given table.
     49    If found, return 0 and set *RESULT to it.  Otherwise return -1.  */
     50 extern int hash_find_entry (hash_table *htab,
     51 			    const void *key, size_t keylen,
     52 			    void **result);
     53 
     54 /* Try to insert the pair (KEY[0..KEYLEN-1], DATA) in the hash table.
     55    Return non-NULL (more precisely, the address of the KEY inside the table's
     56    memory pool) if successful, or NULL if there is already an entry with the
     57    given key.  */
     58 extern const void * hash_insert_entry (hash_table *htab,
     59 				       const void *key, size_t keylen,
     60 				       void *data);
     61 
     62 /* Insert the pair (KEY[0..KEYLEN-1], DATA) in the hash table.
     63    Return 0.  */
     64 extern int hash_set_value (hash_table *htab,
     65 			   const void *key, size_t keylen,
     66 			   void *data);
     67 
     68 /* Steps *PTR forward to the next used entry in the given hash table.  *PTR
     69    should be initially set to NULL.  Store information about the next entry
     70    in *KEY, *KEYLEN, *DATA.
     71    Return 0 normally, -1 when the whole hash table has been traversed.  */
     72 extern int hash_iterate (hash_table *htab, void **ptr,
     73 			 const void **key, size_t *keylen,
     74 			 void **data);
     75 
     76 /* Steps *PTR forward to the next used entry in the given hash table.  *PTR
     77    should be initially set to NULL.  Store information about the next entry
     78    in *KEY, *KEYLEN, *DATAP.  *DATAP is set to point to the storage of the
     79    value; modifying **DATAP will modify the value of the entry.
     80    Return 0 normally, -1 when the whole hash table has been traversed.  */
     81 extern int hash_iterate_modify (hash_table *htab, void **ptr,
     82 				const void **key, size_t *keylen,
     83 				void ***datap);
     84 
     85 /* Given SEED > 1, return the smallest odd prime number >= SEED.  */
     86 extern unsigned long int next_prime (unsigned long int seed);
     87 
     88 #ifdef __cplusplus
     89 }
     90 #endif
     91 
     92 #endif /* not _HASH_H */
     93