include/hash.h

   1 /*
   2  * $Id$
   3  */
   4 #ifndef SQUID_HASH_H
   5 #define SQUID_HASH_H
   6
   7 #include "config.h"
   8
   9 typedef void HASHFREE(void *);
  10 typedef int HASHCMP(const void *, const void *);
  11 typedef unsigned int HASHHASH(const void *, unsigned int);
  12 typedef struct _hash_link hash_link;
  13 typedef struct _hash_table hash_table;
  14
  15 struct _hash_link {
  16     void *key;
  17     hash_link *next;
  18 };
  19
  20 struct _hash_table {
  21     hash_link **buckets;
  22     HASHCMP *cmp;
  23     HASHHASH *hash;
  24     unsigned int size;
  25     unsigned int current_slot;
  26     hash_link *next;
  27     int count;
  28 };
  29
  30 SQUIDCEXTERN hash_table *hash_create(HASHCMP *, int, HASHHASH *);
  31 SQUIDCEXTERN void hash_join(hash_table *, hash_link *);
  32 SQUIDCEXTERN void hash_remove_link(hash_table *, hash_link *);
  33 SQUIDCEXTERN int hashPrime(int n);
  34 SQUIDCEXTERN hash_link *hash_lookup(hash_table *, const void *);
  35 SQUIDCEXTERN void hash_first(hash_table *);
  36 SQUIDCEXTERN hash_link *hash_next(hash_table *);
  37 SQUIDCEXTERN void hash_last(hash_table *);
  38 SQUIDCEXTERN hash_link *hash_get_bucket(hash_table *, unsigned int);
  39 SQUIDCEXTERN void hashFreeMemory(hash_table *);
  40 SQUIDCEXTERN void hashFreeItems(hash_table *, HASHFREE *);
  41 SQUIDCEXTERN HASHHASH hash_string;
  42 SQUIDCEXTERN HASHHASH hash4;
  43 SQUIDCEXTERN const char *hashKeyStr(hash_link *);
  44
  45 /*
  46  *  Here are some good prime number choices.  It's important not to
  47  *  choose a prime number that is too close to exact powers of 2.
  48  *
  49  *  HASH_SIZE 103               // prime number < 128
  50  *  HASH_SIZE 229               // prime number < 256
  51  *  HASH_SIZE 467               // prime number < 512
  52  *  HASH_SIZE 977               // prime number < 1024
  53  *  HASH_SIZE 1979              // prime number < 2048
  54  *  HASH_SIZE 4019              // prime number < 4096
  55  *  HASH_SIZE 6037              // prime number < 6144
  56  *  HASH_SIZE 7951              // prime number < 8192
  57  *  HASH_SIZE 12149             // prime number < 12288
  58  *  HASH_SIZE 16231             // prime number < 16384
  59  *  HASH_SIZE 33493             // prime number < 32768
  60  *  HASH_SIZE 65357             // prime number < 65536
  61  */
  62 #define  DEFAULT_HASH_SIZE 7951 /* prime number < 8192 */
  63
  64 #endif /* SQUID_HASH_H */