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Diffstat (limited to 'hash.h')
| -rw-r--r-- | hash.h | 124 |
1 files changed, 124 insertions, 0 deletions
@@ -0,0 +1,124 @@ +/* hash.h -- decls for hash table + Copyright (C) 1986, 1995 Greg McGary + + 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; either version 2, 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 General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; see the file COPYING. If not, write to the + Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. +*/ + +#ifndef _hash_h_ +#define _hash_h_ + +typedef unsigned long (*hash_t) __P((void const *key)); +typedef int (*hash_cmp_t) __P((void const *x, void const *y)); + +struct hash_table +{ + void **ht_vec; + unsigned long ht_size; /* total number of slots (power of 2) */ + unsigned long ht_capacity; /* usable slots, limited by loading-factor */ + unsigned long ht_fill; /* items in table */ + unsigned long ht_probes; /* number of comparisons */ + unsigned long ht_lookups; /* number of queries */ + unsigned int ht_rehashes; /* number of times we've expanded table */ + hash_t ht_hash_1; /* primary hash function */ + hash_t ht_hash_2; /* secondary hash function */ + hash_cmp_t ht_compare; /* comparison function */ +}; + +void hash_init __P((struct hash_table* ht, long size, + hash_t hash_1, hash_t hash_2, hash_cmp_t hash_cmp)); +void rehash __P((struct hash_table* ht)); +void **hash_lookup __P((struct hash_table* ht, void const *key)); + + +/* hash and comparison macros for string keys. */ + +#define STRING_HASH_1(_key_, _result_) { \ + unsigned char const *kk = (unsigned char const *) (_key_) - 1; \ + while (*++kk) \ + (_result_) += (*kk << (kk[1] & 0xf)); \ +} while (0) +#define return_STRING_HASH_1(_key_) { \ + unsigned long result = 0; \ + STRING_HASH_1 ((_key_), result); \ + return result; \ +} while (0) + +#define STRING_HASH_2(_key_, _result_) { \ + unsigned char const *kk = (unsigned char const *) (_key_) - 1; \ + while (*++kk) \ + (_result_) += (*kk << (kk[1] & 0x7)); \ +} while (0) +#define return_STRING_HASH_2(_key_) { \ + unsigned long result = 0; \ + STRING_HASH_2 ((_key_), result); \ + return result; \ +} while (0) + +#define STRING_COMPARE(_x_, _y_, _result_) { \ + unsigned char const *xx = (unsigned char const *) (_x_) - 1; \ + unsigned char const *yy = (unsigned char const *) (_y_) - 1; \ + do { \ + if (*++xx == '\0') { \ + yy++; \ + break; \ + } \ + } while (*xx == *++yy); \ + (_result_) = *xx - *yy; \ +} while (0) +#define return_STRING_COMPARE(_x_, _y_) { \ + int result; \ + STRING_COMPARE (_x_, _y_, result); \ + return result; \ +} while (0) + +/* hash and comparison macros for integer keys. */ + +#define INTEGER_HASH_1(_key_, _result_) { \ + (_result_) = ((unsigned long)(_key_)); \ +} while (0) +#define return_INTEGER_HASH_1(_key_) { \ + unsigned long result = 0; \ + INTEGER_HASH_1 ((_key_), result); \ + return result; \ +} while (0) + +#define INTEGER_HASH_2(_key_, _result_) { \ + (_result_) = ~((unsigned long)(_key_)); \ +} while (0) +#define return_INTEGER_HASH_2(_key_) { \ + unsigned long result = 0; \ + INTEGER_HASH_2 ((_key_), result); \ + return result; \ +} while (0) + +#define INTEGER_COMPARE(_x_, _y_, _result_) { \ + (_result_) = _x_ - _y_; \ +} while (0) +#define return_INTEGER_COMPARE(_x_, _y_) { \ + int result; \ + INTEGER_COMPARE (_x_, _y_, result); \ + return result; \ +} while (0) + +/* hash and comparison macros for address keys. */ + +#define ADDRESS_HASH_1(_key_, _result_) INTEGER_HASH_1 (((unsigned long)(_key_)) >> 3, (_result_)) +#define ADDRESS_HASH_2(_key_, _result_) INTEGER_HASH_2 (((unsigned long)(_key_)) >> 3, (_result_)) +#define ADDRESS_COMPARE(_x_, _y_, _result_) INTEGER_COMPARE ((_x_), (_y_), (_result_)) +#define return_ADDRESS_HASH_1(_key_) return_INTEGER_HASH_1 (((unsigned long)(_key_)) >> 3) +#define return_ADDRESS_HASH_2(_key_) return_INTEGER_HASH_2 (((unsigned long)(_key_)) >> 3) +#define return_ADDRESS_COMPARE(_x_, _y_) return_INTEGER_COMPARE ((_x_), (_y_)) + +#endif /* not _hash_h_ */ |