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4fd56724ad
This is about twice as fast as the current hash, and removes the need for double hashing (improving locality of reference). The hash function is based on Bob Jenkins' design, slightly adapted wherever Make needs to hash NUL-terminated strings. The old hash function is kept for case-insensitive hashing. This saves 8.5% on QEMU's no-op build (from 12.87s to 11.78s). * configure.ac: Check endianness. * hash.c (rol32, jhash_mix, jhash_final, JHASH_INITVAL, sum_get_unaligned_32, jhash): New. * hash.h (STRING_HASH_1, STRING_N_HASH_1): Use jhash. (STRING_HASH_2, STRING_N_HASH_2): Return a dummy value. (STRING_N_COMPARE, return_STRING_N_COMPARE): Prefer memcmp to strncmp.
235 lines
8.3 KiB
C
235 lines
8.3 KiB
C
/* hash.h -- decls for hash table
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Copyright (C) 1995, 1999, 2002, 2010 Free Software Foundation, Inc.
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Written by Greg McGary <gkm@gnu.org> <greg@mcgary.org>
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GNU Make is free software; you can redistribute it and/or modify it under the
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terms of the GNU General Public License as published by the Free Software
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Foundation; either version 3 of the License, or (at your option) any later
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version.
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GNU Make is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
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A PARTICULAR PURPOSE. See the GNU General Public License for more details.
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You should have received a copy of the GNU General Public License along with
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this program. If not, see <http://www.gnu.org/licenses/>. */
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#ifndef _hash_h_
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#define _hash_h_
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#include <stdio.h>
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#include <ctype.h>
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#if defined __cplusplus || (defined __STDC__ && __STDC__) || defined WINDOWS32
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# if !defined __GLIBC__ || !defined __P
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# undef __P
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# define __P(protos) protos
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# endif
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#else /* Not C++ or ANSI C. */
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# undef __P
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# define __P(protos) ()
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/* We can get away without defining 'const' here only because in this file
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it is used only inside the prototype for 'fnmatch', which is elided in
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non-ANSI C where 'const' is problematical. */
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#endif /* C++ or ANSI C. */
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typedef unsigned long (*hash_func_t) __P((void const *key));
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typedef int (*hash_cmp_func_t) __P((void const *x, void const *y));
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typedef void (*hash_map_func_t) __P((void const *item));
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typedef void (*hash_map_arg_func_t) __P((void const *item, void *arg));
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struct hash_table
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{
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void **ht_vec;
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hash_func_t ht_hash_1; /* primary hash function */
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hash_func_t ht_hash_2; /* secondary hash function */
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hash_cmp_func_t ht_compare; /* comparison function */
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unsigned long ht_size; /* total number of slots (power of 2) */
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unsigned long ht_capacity; /* usable slots, limited by loading-factor */
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unsigned long ht_fill; /* items in table */
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unsigned long ht_empty_slots; /* empty slots not including deleted slots */
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unsigned long ht_collisions; /* # of failed calls to comparison function */
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unsigned long ht_lookups; /* # of queries */
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unsigned int ht_rehashes; /* # of times we've expanded table */
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};
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typedef int (*qsort_cmp_t) __P((void const *, void const *));
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void hash_init __P((struct hash_table *ht, unsigned long size,
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hash_func_t hash_1, hash_func_t hash_2, hash_cmp_func_t hash_cmp));
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void hash_load __P((struct hash_table *ht, void *item_table,
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unsigned long cardinality, unsigned long size));
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void **hash_find_slot __P((struct hash_table *ht, void const *key));
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void *hash_find_item __P((struct hash_table *ht, void const *key));
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void *hash_insert __P((struct hash_table *ht, const void *item));
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void *hash_insert_at __P((struct hash_table *ht, const void *item, void const *slot));
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void *hash_delete __P((struct hash_table *ht, void const *item));
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void *hash_delete_at __P((struct hash_table *ht, void const *slot));
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void hash_delete_items __P((struct hash_table *ht));
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void hash_free_items __P((struct hash_table *ht));
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void hash_free __P((struct hash_table *ht, int free_items));
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void hash_map __P((struct hash_table *ht, hash_map_func_t map));
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void hash_map_arg __P((struct hash_table *ht, hash_map_arg_func_t map, void *arg));
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void hash_print_stats __P((struct hash_table *ht, FILE *out_FILE));
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void **hash_dump __P((struct hash_table *ht, void **vector_0, qsort_cmp_t compare));
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extern unsigned jhash(unsigned char const *key, int n);
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extern unsigned jhash_string(unsigned char const *key);
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extern void *hash_deleted_item;
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#define HASH_VACANT(item) ((item) == 0 || (void *) (item) == hash_deleted_item)
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/* hash and comparison macros for case-sensitive string keys. */
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/* Due to the strcache, it's not uncommon for the string pointers to
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be identical. Take advantage of that to short-circuit string compares. */
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#define STRING_HASH_1(KEY, RESULT) do { \
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unsigned char const *_key_ = (unsigned char const *) (KEY); \
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(RESULT) += jhash_string(_key_); \
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} while (0)
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#define return_STRING_HASH_1(KEY) do { \
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unsigned long _result_ = 0; \
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STRING_HASH_1 ((KEY), _result_); \
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return _result_; \
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} while (0)
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/* No need for a second hash because jhash already provides
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pretty good results. However, do evaluate the arguments
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to avoid warnings. */
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#define STRING_HASH_2(KEY, RESULT) do { \
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(void)(KEY); \
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} while (0)
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#define return_STRING_HASH_2(KEY) do { \
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unsigned long _result_ = 0; \
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STRING_HASH_2 ((KEY), _result_); \
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return _result_; \
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} while (0)
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#define STRING_COMPARE(X, Y, RESULT) do { \
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RESULT = (X) == (Y) ? 0 : strcmp ((X), (Y)); \
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} while (0)
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#define return_STRING_COMPARE(X, Y) do { \
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return (X) == (Y) ? 0 : strcmp ((X), (Y)); \
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} while (0)
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#define STRING_N_HASH_1(KEY, N, RESULT) do { \
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unsigned char const *_key_ = (unsigned char const *) (KEY); \
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(RESULT) += jhash(_key_, N); \
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} while (0)
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#define return_STRING_N_HASH_1(KEY, N) do { \
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unsigned long _result_ = 0; \
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STRING_N_HASH_1 ((KEY), (N), _result_); \
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return _result_; \
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} while (0)
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/* No need for a second hash because jhash already provides
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pretty good results. However, do evaluate the arguments
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to avoid warnings. */
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#define STRING_N_HASH_2(KEY, N, RESULT) do { \
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(void)(KEY); \
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(void)(N); \
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} while (0)
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#define return_STRING_N_HASH_2(KEY, N) do { \
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unsigned long _result_ = 0; \
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STRING_N_HASH_2 ((KEY), (N), _result_); \
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return _result_; \
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} while (0)
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#define STRING_N_COMPARE(X, Y, N, RESULT) do { \
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RESULT = (X) == (Y) ? 0 : memcmp ((X), (Y), (N)); \
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} while (0)
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#define return_STRING_N_COMPARE(X, Y, N) do { \
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return (X) == (Y) ? 0 : memcmp ((X), (Y), (N)); \
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} while (0)
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#ifdef HAVE_CASE_INSENSITIVE_FS
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/* hash and comparison macros for case-insensitive string _key_s. */
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#define ISTRING_HASH_1(KEY, RESULT) do { \
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unsigned char const *_key_ = (unsigned char const *) (KEY) - 1; \
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while (*++_key_) \
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(RESULT) += ((isupper (*_key_) ? tolower (*_key_) : *_key_) << (_key_[1] & 0xf)); \
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} while (0)
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#define return_ISTRING_HASH_1(KEY) do { \
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unsigned long _result_ = 0; \
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ISTRING_HASH_1 ((KEY), _result_); \
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return _result_; \
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} while (0)
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#define ISTRING_HASH_2(KEY, RESULT) do { \
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unsigned char const *_key_ = (unsigned char const *) (KEY) - 1; \
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while (*++_key_) \
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(RESULT) += ((isupper (*_key_) ? tolower (*_key_) : *_key_) << (_key_[1] & 0x7)); \
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} while (0)
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#define return_ISTRING_HASH_2(KEY) do { \
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unsigned long _result_ = 0; \
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ISTRING_HASH_2 ((KEY), _result_); \
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return _result_; \
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} while (0)
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#define ISTRING_COMPARE(X, Y, RESULT) do { \
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RESULT = (X) == (Y) ? 0 : strcasecmp ((X), (Y)); \
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} while (0)
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#define return_ISTRING_COMPARE(X, Y) do { \
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return (X) == (Y) ? 0 : strcasecmp ((X), (Y)); \
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} while (0)
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#else
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#define ISTRING_HASH_1(KEY, RESULT) STRING_HASH_1 ((KEY), (RESULT))
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#define return_ISTRING_HASH_1(KEY) return_STRING_HASH_1 (KEY)
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#define ISTRING_HASH_2(KEY, RESULT) STRING_HASH_2 ((KEY), (RESULT))
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#define return_ISTRING_HASH_2(KEY) return_STRING_HASH_2 (KEY)
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#define ISTRING_COMPARE(X, Y, RESULT) STRING_COMPARE ((X), (Y), (RESULT))
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#define return_ISTRING_COMPARE(X, Y) return_STRING_COMPARE ((X), (Y))
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#endif
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/* hash and comparison macros for integer _key_s. */
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#define INTEGER_HASH_1(KEY, RESULT) do { \
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(RESULT) += ((unsigned long)(KEY)); \
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} while (0)
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#define return_INTEGER_HASH_1(KEY) do { \
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unsigned long _result_ = 0; \
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INTEGER_HASH_1 ((KEY), _result_); \
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return _result_; \
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} while (0)
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#define INTEGER_HASH_2(KEY, RESULT) do { \
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(RESULT) += ~((unsigned long)(KEY)); \
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} while (0)
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#define return_INTEGER_HASH_2(KEY) do { \
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unsigned long _result_ = 0; \
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INTEGER_HASH_2 ((KEY), _result_); \
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return _result_; \
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} while (0)
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#define INTEGER_COMPARE(X, Y, RESULT) do { \
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(RESULT) = X - Y; \
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} while (0)
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#define return_INTEGER_COMPARE(X, Y) do { \
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int _result_; \
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INTEGER_COMPARE (X, Y, _result_); \
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return _result_; \
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} while (0)
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/* hash and comparison macros for address keys. */
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#define ADDRESS_HASH_1(KEY, RESULT) INTEGER_HASH_1 (((unsigned long)(KEY)) >> 3, (RESULT))
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#define ADDRESS_HASH_2(KEY, RESULT) INTEGER_HASH_2 (((unsigned long)(KEY)) >> 3, (RESULT))
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#define ADDRESS_COMPARE(X, Y, RESULT) INTEGER_COMPARE ((X), (Y), (RESULT))
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#define return_ADDRESS_HASH_1(KEY) return_INTEGER_HASH_1 (((unsigned long)(KEY)) >> 3)
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#define return_ADDRESS_HASH_2(KEY) return_INTEGER_HASH_2 (((unsigned long)(KEY)) >> 3)
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#define return_ADDRESS_COMPARE(X, Y) return_INTEGER_COMPARE ((X), (Y))
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#endif /* not _hash_h_ */
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