2 * Copyright (C) 1995-2011 University of Karlsruhe. All right reserved.
4 * This file is part of libFirm.
6 * This file may be distributed and/or modified under the terms of the
7 * GNU General Public License version 2 as published by the Free Software
8 * Foundation and appearing in the file LICENSE.GPL included in the
9 * packaging of this file.
11 * Licensees holding valid libFirm Professional Edition licenses may use
12 * this file in accordance with the libFirm Commercial License.
13 * Agreement provided with the Software.
15 * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
16 * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * @brief Hash functions
23 * @author Michael Beck, Sebastian Hack
25 #ifndef FIRM_ADT_HASHPTR_H
26 #define FIRM_ADT_HASHPTR_H
33 * @defgroup hashptr Hash Functions
39 #define _FIRM_FNV_OFFSET_BASIS 2166136261U
40 #define _FIRM_FNV_FNV_PRIME 16777619U
42 /* Computing x * _FIRM_FNV_FNV_PRIME */
43 #define _FIRM_FNV_TIMES_PRIME(x) ((x) * _FIRM_FNV_FNV_PRIME)
48 * Returns a hash value for a block of data.
50 static inline unsigned hash_data(const unsigned char *data, size_t bytes)
53 unsigned hash = _FIRM_FNV_OFFSET_BASIS;
55 for(i = 0; i < bytes; ++i) {
56 hash = _FIRM_FNV_TIMES_PRIME(hash);
64 * Returns a hash value for a string.
65 * @param str The string (can be const).
66 * @return A hash value for the string.
68 static inline unsigned hash_str(const char *str)
71 unsigned hash = _FIRM_FNV_OFFSET_BASIS;
73 for(i = 0; str[i] != '\0'; ++i) {
74 hash = _FIRM_FNV_TIMES_PRIME(hash);
82 * Returns a hash value for a pointer.
83 * Pointer addresses are mostly aligned to 4 or 8 bytes. So we remove the
86 static inline unsigned hash_ptr(const void *ptr)
88 return ((unsigned)(((char *) (ptr) - (char *)0) >> 3));
92 * Combines 2 hash values.
93 * @param x One hash value.
94 * @param y Another hash value.
95 * @return A hash value computed from both.
97 static inline unsigned hash_combine(unsigned x, unsigned y)
99 unsigned hash = _FIRM_FNV_TIMES_PRIME(_FIRM_FNV_OFFSET_BASIS);
101 hash = _FIRM_FNV_TIMES_PRIME(hash);