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 function for pointers
23 * @author Michael Beck, Sebastian Hack
25 #ifndef FIRM_ADT_HASHPTR_H
26 #define FIRM_ADT_HASHPTR_H
31 #define _FIRM_FNV_OFFSET_BASIS 2166136261U
32 #define _FIRM_FNV_FNV_PRIME 16777619U
34 /* Computing x * _FIRM_FNV_FNV_PRIME */
35 #define _FIRM_FNV_TIMES_PRIME(x) ((x) * _FIRM_FNV_FNV_PRIME)
37 static inline unsigned hash_data(const unsigned char *data, size_t bytes)
40 unsigned hash = _FIRM_FNV_OFFSET_BASIS;
42 for(i = 0; i < bytes; ++i) {
43 hash = _FIRM_FNV_TIMES_PRIME(hash);
51 * Returns a hash value for a string.
52 * @param str The string (can be const).
53 * @param len The length of the string.
54 * @return A hash value for the string.
56 static inline unsigned hash_str(const char *data)
59 unsigned hash = _FIRM_FNV_OFFSET_BASIS;
61 for(i = 0; data[i] != '\0'; ++i) {
62 hash = _FIRM_FNV_TIMES_PRIME(hash);
70 * Returns a hash value for a pointer.
71 * Pointer addresses are mostly aligned to 4 or 8 bytes. So we remove the
74 static inline unsigned hash_ptr(const void *ptr)
76 return ((unsigned)(((char *) (ptr) - (char *)0) >> 3));
80 * Combines 2 hash values.
81 * @param a One hash value.
82 * @param b Another hash value.
83 * @return A hash value computed from both.
85 static inline unsigned hash_combine(unsigned x, unsigned y)
87 unsigned hash = _FIRM_FNV_TIMES_PRIME(_FIRM_FNV_OFFSET_BASIS);
89 hash = _FIRM_FNV_TIMES_PRIME(hash);