xref: /PHP-5.4/ext/hash/hash_fnv.c (revision c0d060f5)
1 /*
2   +----------------------------------------------------------------------+
3   | PHP Version 5                                                        |
4   +----------------------------------------------------------------------+
5   | Copyright (c) 1997-2014 The PHP Group                                |
6   +----------------------------------------------------------------------+
7   | This source file is subject to version 3.01 of the PHP license,      |
8   | that is bundled with this package in the file LICENSE, and is        |
9   | available through the world-wide-web at the following url:           |
10   | http://www.php.net/license/3_01.txt                                  |
11   | If you did not receive a copy of the PHP license and are unable to   |
12   | obtain it through the world-wide-web, please send a note to          |
13   | license@php.net so we can mail you a copy immediately.               |
14   +----------------------------------------------------------------------+
15   | Author: Michael Maclean <mgdm@php.net>                               |
16   +----------------------------------------------------------------------+
17 */
18 
19 /* $Id$ */
20 
21 /*  Based on the public domain algorithm found at
22 	http://www.isthe.com/chongo/tech/comp/fnv/index.html */
23 
24 #include "php_hash.h"
25 #include "php_hash_fnv.h"
26 
27 const php_hash_ops php_hash_fnv132_ops = {
28 	(php_hash_init_func_t) PHP_FNV132Init,
29 	(php_hash_update_func_t) PHP_FNV132Update,
30 	(php_hash_final_func_t) PHP_FNV132Final,
31 	(php_hash_copy_func_t) php_hash_copy,
32 	4,
33 	4,
34 	sizeof(PHP_FNV132_CTX)
35 };
36 
37 	const php_hash_ops php_hash_fnv1a32_ops = {
38 	(php_hash_init_func_t) PHP_FNV132Init,
39 	(php_hash_update_func_t) PHP_FNV1a32Update,
40  	(php_hash_final_func_t) PHP_FNV132Final,
41 	(php_hash_copy_func_t) php_hash_copy,
42 	4,
43 	4,
44 	sizeof(PHP_FNV132_CTX)
45 };
46 
47 const php_hash_ops php_hash_fnv164_ops = {
48 	(php_hash_init_func_t) PHP_FNV164Init,
49 	(php_hash_update_func_t) PHP_FNV164Update,
50 	(php_hash_final_func_t) PHP_FNV164Final,
51 	(php_hash_copy_func_t) php_hash_copy,
52 	8,
53 	4,
54 	sizeof(PHP_FNV164_CTX)
55 };
56 
57 const php_hash_ops php_hash_fnv1a64_ops = {
58 	(php_hash_init_func_t) PHP_FNV164Init,
59 	(php_hash_update_func_t) PHP_FNV1a64Update,
60  	(php_hash_final_func_t) PHP_FNV164Final,
61 	(php_hash_copy_func_t) php_hash_copy,
62 	8,
63 	4,
64 	sizeof(PHP_FNV164_CTX)
65 };
66 
67 /* {{{ PHP_FNV132Init
68  * 32-bit FNV-1 hash initialisation
69  */
PHP_FNV132Init(PHP_FNV132_CTX * context)70 PHP_HASH_API void PHP_FNV132Init(PHP_FNV132_CTX *context)
71 {
72 	context->state = PHP_FNV1_32_INIT;
73 }
74 /* }}} */
75 
PHP_FNV132Update(PHP_FNV132_CTX * context,const unsigned char * input,unsigned int inputLen)76 PHP_HASH_API void PHP_FNV132Update(PHP_FNV132_CTX *context, const unsigned char *input,
77 		unsigned int inputLen)
78 {
79 	context->state = fnv_32_buf((void *)input, inputLen, context->state, 0);
80 }
81 
PHP_FNV1a32Update(PHP_FNV132_CTX * context,const unsigned char * input,unsigned int inputLen)82 PHP_HASH_API void PHP_FNV1a32Update(PHP_FNV132_CTX *context, const unsigned char *input,
83 		unsigned int inputLen)
84 {
85 	context->state = fnv_32_buf((void *)input, inputLen, context->state, 1);
86 }
87 
PHP_FNV132Final(unsigned char digest[4],PHP_FNV132_CTX * context)88 PHP_HASH_API void PHP_FNV132Final(unsigned char digest[4], PHP_FNV132_CTX * context)
89 {
90 #ifdef WORDS_BIGENDIAN
91 	memcpy(digest, &context->state, 4);
92 #else
93 	int i = 0;
94 	unsigned char *c = (unsigned char *) &context->state;
95 
96 	for (i = 0; i < 4; i++) {
97 		digest[i] = c[3 - i];
98 	}
99 #endif
100 }
101 
102 /* {{{ PHP_FNV164Init
103  * 64-bit FNV-1 hash initialisation
104  */
PHP_FNV164Init(PHP_FNV164_CTX * context)105 PHP_HASH_API void PHP_FNV164Init(PHP_FNV164_CTX *context)
106 {
107 	context->state = PHP_FNV1_64_INIT;
108 }
109 /* }}} */
110 
PHP_FNV164Update(PHP_FNV164_CTX * context,const unsigned char * input,unsigned int inputLen)111 PHP_HASH_API void PHP_FNV164Update(PHP_FNV164_CTX *context, const unsigned char *input,
112 		unsigned int inputLen)
113 {
114 	context->state = fnv_64_buf((void *)input, inputLen, context->state, 0);
115 }
116 
PHP_FNV1a64Update(PHP_FNV164_CTX * context,const unsigned char * input,unsigned int inputLen)117 PHP_HASH_API void PHP_FNV1a64Update(PHP_FNV164_CTX *context, const unsigned char *input,
118 		unsigned int inputLen)
119 {
120 	context->state = fnv_64_buf((void *)input, inputLen, context->state, 1);
121 }
122 
PHP_FNV164Final(unsigned char digest[8],PHP_FNV164_CTX * context)123 PHP_HASH_API void PHP_FNV164Final(unsigned char digest[8], PHP_FNV164_CTX * context)
124 {
125 #ifdef WORDS_BIGENDIAN
126 	memcpy(digest, &context->state, 8);
127 #else
128 	int i = 0;
129 	unsigned char *c = (unsigned char *) &context->state;
130 
131 	for (i = 0; i < 8; i++) {
132 		digest[i] = c[7 - i];
133 	}
134 #endif
135 }
136 
137 
138 /*
139  * fnv_32_buf - perform a 32 bit Fowler/Noll/Vo hash on a buffer
140  *
141  * input:
142  *  buf - start of buffer to hash
143  *  len - length of buffer in octets
144  *  hval	- previous hash value or 0 if first call
145  *  alternate - if > 0 use the alternate version
146  *
147  * returns:
148  *  32 bit hash as a static hash type
149  */
150 static php_hash_uint32
fnv_32_buf(void * buf,size_t len,php_hash_uint32 hval,int alternate)151 fnv_32_buf(void *buf, size_t len, php_hash_uint32 hval, int alternate)
152 {
153 	unsigned char *bp = (unsigned char *)buf;   /* start of buffer */
154 	unsigned char *be = bp + len;	   /* beyond end of buffer */
155 
156 	/*
157 	 * FNV-1 hash each octet in the buffer
158 	 */
159 	while (bp < be) {
160 
161 		if (alternate == 0) {
162 			/* multiply by the 32 bit FNV magic prime mod 2^32 */
163 			hval *= PHP_FNV_32_PRIME;
164 
165 			/* xor the bottom with the current octet */
166 			hval ^= (php_hash_uint32)*bp++;
167 		} else {
168 			/* xor the bottom with the current octet */
169 			hval ^= (php_hash_uint32)*bp++;
170 
171 			/* multiply by the 32 bit FNV magic prime mod 2^32 */
172 			hval *= PHP_FNV_32_PRIME;
173 		}
174 	}
175 
176 	/* return our new hash value */
177 	return hval;
178 }
179 
180 /*
181  * fnv_64_buf - perform a 64 bit Fowler/Noll/Vo hash on a buffer
182  *
183  * input:
184  *  buf - start of buffer to hash
185  *  len - length of buffer in octets
186  *  hval	- previous hash value or 0 if first call
187  *  alternate - if > 0 use the alternate version
188  *
189  * returns:
190  *  64 bit hash as a static hash type
191  */
192 static php_hash_uint64
fnv_64_buf(void * buf,size_t len,php_hash_uint64 hval,int alternate)193 fnv_64_buf(void *buf, size_t len, php_hash_uint64 hval, int alternate)
194 {
195 	unsigned char *bp = (unsigned char *)buf;   /* start of buffer */
196 	unsigned char *be = bp + len;	   /* beyond end of buffer */
197 
198 	/*
199 	 * FNV-1 hash each octet of the buffer
200 	 */
201 	while (bp < be) {
202 
203 		if (alternate == 0) {
204 			/* multiply by the 64 bit FNV magic prime mod 2^64 */
205 			hval *= PHP_FNV_64_PRIME;
206 
207 			/* xor the bottom with the current octet */
208 			hval ^= (php_hash_uint64)*bp++;
209 		 } else {
210 			/* xor the bottom with the current octet */
211 			hval ^= (php_hash_uint64)*bp++;
212 
213 			/* multiply by the 64 bit FNV magic prime mod 2^64 */
214 			hval *= PHP_FNV_64_PRIME;
215 		 }
216 	}
217 
218 	/* return our new hash value */
219 	return hval;
220 }
221 
222 /*
223  * Local variables:
224  * tab-width: 4
225  * c-basic-offset: 4
226  * End:
227  * vim600: noet sw=4 ts=4 fdm=marker
228  * vim<600: noet sw=4 ts=4
229  */
230