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4d3a042d YO |
1 | /* hash a key |
2 | *-------------------------------------------------------------------------------------- | |
3 | * The "hash seed" feature was added in Perl 5.8.1 to perturb the results | |
4 | * to avoid "algorithmic complexity attacks". | |
5 | * | |
6 | * If USE_HASH_SEED is defined, hash randomisation is done by default | |
7 | * If USE_HASH_SEED_EXPLICIT is defined, hash randomisation is done | |
8 | * only if the environment variable PERL_HASH_SEED is set. | |
9 | * (see also perl.c:perl_parse() and S_init_tls_and_interp() and util.c:get_hash_seed()) | |
10 | */ | |
11 | ||
12 | #ifndef PERL_SEEN_HV_FUNC_H /* compile once */ | |
13 | #define PERL_SEEN_HV_FUNC_H | |
14 | ||
15 | #if !( 0 \ | |
e6b54db6 | 16 | || defined(PERL_HASH_FUNC_SIPHASH) \ |
4d3a042d YO |
17 | || defined(PERL_HASH_FUNC_SDBM) \ |
18 | || defined(PERL_HASH_FUNC_DJB2) \ | |
19 | || defined(PERL_HASH_FUNC_SUPERFAST) \ | |
20 | || defined(PERL_HASH_FUNC_MURMUR3) \ | |
21 | || defined(PERL_HASH_FUNC_ONE_AT_A_TIME) \ | |
b1300a73 | 22 | || defined(PERL_HASH_FUNC_ONE_AT_A_TIME_HARD) \ |
4d3a042d YO |
23 | || defined(PERL_HASH_FUNC_ONE_AT_A_TIME_OLD) \ |
24 | ) | |
b1300a73 | 25 | #define PERL_HASH_FUNC_ONE_AT_A_TIME_HARD |
4d3a042d | 26 | #endif |
4d3a042d YO |
27 | |
28 | #if defined(PERL_HASH_FUNC_SIPHASH) | |
29 | # define PERL_HASH_FUNC "SIPHASH_2_4" | |
30 | # define PERL_HASH_SEED_BYTES 16 | |
31 | # define PERL_HASH(hash,str,len) (hash)= S_perl_hash_siphash_2_4(PERL_HASH_SEED,(U8*)(str),(len)) | |
32 | #elif defined(PERL_HASH_FUNC_SUPERFAST) | |
33 | # define PERL_HASH_FUNC "SUPERFAST" | |
34 | # define PERL_HASH_SEED_BYTES 4 | |
35 | # define PERL_HASH(hash,str,len) (hash)= S_perl_hash_superfast(PERL_HASH_SEED,(U8*)(str),(len)) | |
36 | #elif defined(PERL_HASH_FUNC_MURMUR3) | |
37 | # define PERL_HASH_FUNC "MURMUR3" | |
38 | # define PERL_HASH_SEED_BYTES 4 | |
39 | # define PERL_HASH(hash,str,len) (hash)= S_perl_hash_murmur3(PERL_HASH_SEED,(U8*)(str),(len)) | |
40 | #elif defined(PERL_HASH_FUNC_DJB2) | |
41 | # define PERL_HASH_FUNC "DJB2" | |
42 | # define PERL_HASH_SEED_BYTES 4 | |
43 | # define PERL_HASH(hash,str,len) (hash)= S_perl_hash_djb2(PERL_HASH_SEED,(U8*)(str),(len)) | |
44 | #elif defined(PERL_HASH_FUNC_SDBM) | |
45 | # define PERL_HASH_FUNC "SDBM" | |
46 | # define PERL_HASH_SEED_BYTES 4 | |
47 | # define PERL_HASH(hash,str,len) (hash)= S_perl_hash_sdbm(PERL_HASH_SEED,(U8*)(str),(len)) | |
b1300a73 YO |
48 | #elif defined(PERL_HASH_FUNC_ONE_AT_A_TIME_HARD) |
49 | # define PERL_HASH_FUNC "ONE_AT_A_TIME_HARD" | |
50 | # define PERL_HASH_SEED_BYTES 8 | |
51 | # define PERL_HASH(hash,str,len) (hash)= S_perl_hash_one_at_a_time_hard(PERL_HASH_SEED,(U8*)(str),(len)) | |
4d3a042d YO |
52 | #elif defined(PERL_HASH_FUNC_ONE_AT_A_TIME) |
53 | # define PERL_HASH_FUNC "ONE_AT_A_TIME" | |
54 | # define PERL_HASH_SEED_BYTES 4 | |
55 | # define PERL_HASH(hash,str,len) (hash)= S_perl_hash_one_at_a_time(PERL_HASH_SEED,(U8*)(str),(len)) | |
56 | #elif defined(PERL_HASH_FUNC_ONE_AT_A_TIME_OLD) | |
57 | # define PERL_HASH_FUNC "ONE_AT_A_TIME_OLD" | |
58 | # define PERL_HASH_SEED_BYTES 4 | |
59 | # define PERL_HASH(hash,str,len) (hash)= S_perl_hash_old_one_at_a_time(PERL_HASH_SEED,(U8*)(str),(len)) | |
60 | #endif | |
61 | ||
62 | #ifndef PERL_HASH | |
63 | #error "No hash function defined!" | |
64 | #endif | |
65 | #ifndef PERL_HASH_SEED_BYTES | |
66 | #error "PERL_HASH_SEED_BYTES not defined" | |
67 | #endif | |
68 | #ifndef PERL_HASH_FUNC | |
69 | #error "PERL_HASH_FUNC not defined" | |
70 | #endif | |
71 | ||
72 | #ifndef PERL_HASH_SEED | |
73 | # if defined(USE_HASH_SEED) || defined(USE_HASH_SEED_EXPLICIT) | |
74 | # define PERL_HASH_SEED PL_hash_seed | |
75 | # elif PERL_HASH_SEED_BYTES == 4 | |
76 | # define PERL_HASH_SEED "PeRl" | |
77 | # elif PERL_HASH_SEED_BYTES == 16 | |
78 | # define PERL_HASH_SEED "PeRlHaShhAcKpErl" | |
79 | # else | |
80 | # error "No PERL_HASH_SEED definition for " PERL_HASH_FUNC | |
81 | # endif | |
82 | #endif | |
83 | ||
84 | /*----------------------------------------------------------------------------- | |
85 | * Endianess, misalignment capabilities and util macros | |
86 | * | |
87 | * The following 3 macros are defined in this section. The other macros defined | |
88 | * are only needed to help derive these 3. | |
89 | * | |
90 | * U8TO32_LE(x) Read a little endian unsigned 32-bit int | |
91 | * UNALIGNED_SAFE Defined if READ_UINT32 works on non-word boundaries | |
92 | * ROTL32(x,r) Rotate x left by r bits | |
93 | */ | |
94 | ||
95 | #if (defined(__GNUC__) && defined(__i386__)) || defined(__WATCOMC__) \ | |
96 | || defined(_MSC_VER) || defined (__BORLANDC__) || defined (__TURBOC__) | |
97 | #define U8TO16_LE(d) (*((const U16 *) (d))) | |
98 | #endif | |
99 | ||
100 | #if !defined (U8TO16_LE) | |
101 | #define U8TO16_LE(d) ((((const U8 *)(d))[1] << 8)\ | |
102 | +((const U8 *)(d))[0]) | |
103 | #endif | |
104 | ||
105 | ||
106 | /* Now find best way we can to READ_UINT32 */ | |
107 | #if (BYTEORDER == 0x1234 || BYTEORDER == 0x12345678) && U32SIZE == 4 | |
108 | /* CPU endian matches murmurhash algorithm, so read 32-bit word directly */ | |
109 | #define U8TO32_LE(ptr) (*((U32*)(ptr))) | |
110 | #elif BYTEORDER == 0x4321 || BYTEORDER == 0x87654321 | |
111 | /* TODO: Add additional cases below where a compiler provided bswap32 is available */ | |
112 | #if defined(__GNUC__) && (__GNUC__>4 || (__GNUC__==4 && __GNUC_MINOR__>=3)) | |
113 | #define U8TO32_LE(ptr) (__builtin_bswap32(*((U32*)(ptr)))) | |
114 | #else | |
115 | /* Without a known fast bswap32 we're just as well off doing this */ | |
116 | #define U8TO32_LE(ptr) (ptr[0]|ptr[1]<<8|ptr[2]<<16|ptr[3]<<24) | |
117 | #define UNALIGNED_SAFE | |
118 | #endif | |
119 | #else | |
120 | /* Unknown endianess so last resort is to read individual bytes */ | |
121 | #define U8TO32_LE(ptr) (ptr[0]|ptr[1]<<8|ptr[2]<<16|ptr[3]<<24) | |
122 | /* Since we're not doing word-reads we can skip the messing about with realignment */ | |
123 | #define UNALIGNED_SAFE | |
124 | #endif | |
125 | ||
b716320d YO |
126 | #ifdef HAS_QUAD |
127 | #ifndef U64TYPE | |
128 | /* This probably isn't going to work, but failing with a compiler error due to | |
129 | lack of uint64_t is no worse than failing right now with an #error. */ | |
130 | #define U64TYPE uint64_t | |
131 | #endif | |
132 | #endif | |
133 | ||
134 | /* Find best way to ROTL32/ROTL64 */ | |
4d3a042d YO |
135 | #if defined(_MSC_VER) |
136 | #include <stdlib.h> /* Microsoft put _rotl declaration in here */ | |
137 | #define ROTL32(x,r) _rotl(x,r) | |
b716320d YO |
138 | #ifdef HAS_QUAD |
139 | #define ROTL64(x,r) _rotl64(x,r) | |
140 | #endif | |
4d3a042d YO |
141 | #else |
142 | /* gcc recognises this code and generates a rotate instruction for CPUs with one */ | |
143 | #define ROTL32(x,r) (((U32)x << r) | ((U32)x >> (32 - r))) | |
b716320d YO |
144 | #ifdef HAS_QUAD |
145 | #define ROTL64(x,r) (((U64TYPE)x << r) | ((U64TYPE)x >> (64 - r))) | |
146 | #endif | |
4d3a042d YO |
147 | #endif |
148 | ||
149 | ||
b716320d YO |
150 | #ifdef UV_IS_QUAD |
151 | #define ROTL_UV(x,r) ROTL64(x,r) | |
152 | #else | |
153 | #define ROTL_UV(x,r) ROTL32(x,r) | |
154 | #endif | |
155 | ||
4d3a042d YO |
156 | /* This is SipHash by Jean-Philippe Aumasson and Daniel J. Bernstein. |
157 | * The authors claim it is relatively secure compared to the alternatives | |
158 | * and that performance wise it is a suitable hash for languages like Perl. | |
159 | * See: | |
160 | * | |
161 | * https://www.131002.net/siphash/ | |
162 | * | |
163 | * This implementation seems to perform slightly slower than one-at-a-time for | |
164 | * short keys, but degrades slower for longer keys. Murmur Hash outperforms it | |
165 | * regardless of keys size. | |
166 | * | |
167 | * It is 64 bit only. | |
168 | */ | |
169 | ||
170 | #ifdef HAS_QUAD | |
171 | ||
4d3a042d YO |
172 | #define U8TO64_LE(p) \ |
173 | (((U64TYPE)((p)[0]) ) | \ | |
174 | ((U64TYPE)((p)[1]) << 8) | \ | |
175 | ((U64TYPE)((p)[2]) << 16) | \ | |
176 | ((U64TYPE)((p)[3]) << 24) | \ | |
177 | ((U64TYPE)((p)[4]) << 32) | \ | |
178 | ((U64TYPE)((p)[5]) << 40) | \ | |
179 | ((U64TYPE)((p)[6]) << 48) | \ | |
180 | ((U64TYPE)((p)[7]) << 56)) | |
181 | ||
182 | #define SIPROUND \ | |
183 | do { \ | |
184 | v0 += v1; v1=ROTL64(v1,13); v1 ^= v0; v0=ROTL64(v0,32); \ | |
185 | v2 += v3; v3=ROTL64(v3,16); v3 ^= v2; \ | |
186 | v0 += v3; v3=ROTL64(v3,21); v3 ^= v0; \ | |
187 | v2 += v1; v1=ROTL64(v1,17); v1 ^= v2; v2=ROTL64(v2,32); \ | |
188 | } while(0) | |
189 | ||
190 | /* SipHash-2-4 */ | |
191 | ||
192 | PERL_STATIC_INLINE U32 | |
193 | S_perl_hash_siphash_2_4(const unsigned char * const seed, const unsigned char *in, const STRLEN inlen) { | |
194 | /* "somepseudorandomlygeneratedbytes" */ | |
195 | U64TYPE v0 = 0x736f6d6570736575ULL; | |
196 | U64TYPE v1 = 0x646f72616e646f6dULL; | |
197 | U64TYPE v2 = 0x6c7967656e657261ULL; | |
198 | U64TYPE v3 = 0x7465646279746573ULL; | |
199 | ||
200 | U64TYPE b; | |
201 | U64TYPE k0 = ((U64TYPE*)seed)[0]; | |
202 | U64TYPE k1 = ((U64TYPE*)seed)[1]; | |
203 | U64TYPE m; | |
204 | const int left = inlen & 7; | |
205 | const U8 *end = in + inlen - left; | |
206 | ||
207 | b = ( ( U64TYPE )(inlen) ) << 56; | |
208 | v3 ^= k1; | |
209 | v2 ^= k0; | |
210 | v1 ^= k1; | |
211 | v0 ^= k0; | |
212 | ||
213 | for ( ; in != end; in += 8 ) | |
214 | { | |
215 | m = U8TO64_LE( in ); | |
216 | v3 ^= m; | |
217 | SIPROUND; | |
218 | SIPROUND; | |
219 | v0 ^= m; | |
220 | } | |
221 | ||
222 | switch( left ) | |
223 | { | |
224 | case 7: b |= ( ( U64TYPE )in[ 6] ) << 48; | |
225 | case 6: b |= ( ( U64TYPE )in[ 5] ) << 40; | |
226 | case 5: b |= ( ( U64TYPE )in[ 4] ) << 32; | |
227 | case 4: b |= ( ( U64TYPE )in[ 3] ) << 24; | |
228 | case 3: b |= ( ( U64TYPE )in[ 2] ) << 16; | |
229 | case 2: b |= ( ( U64TYPE )in[ 1] ) << 8; | |
230 | case 1: b |= ( ( U64TYPE )in[ 0] ); break; | |
231 | case 0: break; | |
232 | } | |
233 | ||
234 | v3 ^= b; | |
235 | SIPROUND; | |
236 | SIPROUND; | |
237 | v0 ^= b; | |
238 | ||
239 | v2 ^= 0xff; | |
240 | SIPROUND; | |
241 | SIPROUND; | |
242 | SIPROUND; | |
243 | SIPROUND; | |
244 | b = v0 ^ v1 ^ v2 ^ v3; | |
245 | return (U32)(b & U32_MAX); | |
246 | } | |
247 | #endif /* defined(HAS_QUAD) */ | |
248 | ||
249 | /* FYI: This is the "Super-Fast" algorithm mentioned by Bob Jenkins in | |
250 | * (http://burtleburtle.net/bob/hash/doobs.html) | |
251 | * It is by Paul Hsieh (c) 2004 and is analysed here | |
252 | * http://www.azillionmonkeys.com/qed/hash.html | |
253 | * license terms are here: | |
254 | * http://www.azillionmonkeys.com/qed/weblicense.html | |
255 | */ | |
256 | ||
257 | ||
258 | PERL_STATIC_INLINE U32 | |
259 | S_perl_hash_superfast(const unsigned char * const seed, const unsigned char *str, STRLEN len) { | |
260 | U32 hash = *((U32*)seed) + len; | |
261 | U32 tmp; | |
262 | int rem= len & 3; | |
263 | len >>= 2; | |
264 | ||
265 | for (;len > 0; len--) { | |
266 | hash += U8TO16_LE (str); | |
267 | tmp = (U8TO16_LE (str+2) << 11) ^ hash; | |
268 | hash = (hash << 16) ^ tmp; | |
269 | str += 2 * sizeof (U16); | |
270 | hash += hash >> 11; | |
271 | } | |
272 | ||
273 | /* Handle end cases */ | |
274 | switch (rem) { \ | |
275 | case 3: hash += U8TO16_LE (str); | |
276 | hash ^= hash << 16; | |
277 | hash ^= str[sizeof (U16)] << 18; | |
278 | hash += hash >> 11; | |
279 | break; | |
280 | case 2: hash += U8TO16_LE (str); | |
281 | hash ^= hash << 11; | |
282 | hash += hash >> 17; | |
283 | break; | |
284 | case 1: hash += *str; | |
285 | hash ^= hash << 10; | |
286 | hash += hash >> 1; | |
287 | } | |
288 | /* Force "avalanching" of final 127 bits */ | |
289 | hash ^= hash << 3; | |
290 | hash += hash >> 5; | |
291 | hash ^= hash << 4; | |
292 | hash += hash >> 17; | |
293 | hash ^= hash << 25; | |
294 | return (hash + (hash >> 6)); | |
295 | } | |
296 | ||
297 | ||
298 | /*----------------------------------------------------------------------------- | |
299 | * MurmurHash3 was written by Austin Appleby, and is placed in the public | |
300 | * domain. | |
301 | * | |
302 | * This implementation was originally written by Shane Day, and is also public domain, | |
303 | * and was modified to function as a macro similar to other perl hash functions by | |
304 | * Yves Orton. | |
305 | * | |
306 | * This is a portable ANSI C implementation of MurmurHash3_x86_32 (Murmur3A) | |
307 | * with support for progressive processing. | |
308 | * | |
309 | * If you want to understand the MurmurHash algorithm you would be much better | |
310 | * off reading the original source. Just point your browser at: | |
311 | * http://code.google.com/p/smhasher/source/browse/trunk/MurmurHash3.cpp | |
312 | * | |
313 | * How does it work? | |
314 | * | |
315 | * We can only process entire 32 bit chunks of input, except for the very end | |
316 | * that may be shorter. | |
317 | * | |
318 | * To handle endianess I simply use a macro that reads a U32 and define | |
319 | * that macro to be a direct read on little endian machines, a read and swap | |
320 | * on big endian machines, or a byte-by-byte read if the endianess is unknown. | |
321 | */ | |
322 | ||
323 | ||
324 | /*----------------------------------------------------------------------------- | |
325 | * Core murmurhash algorithm macros */ | |
326 | ||
327 | #define MURMUR_C1 (0xcc9e2d51) | |
328 | #define MURMUR_C2 (0x1b873593) | |
329 | #define MURMUR_C3 (0xe6546b64) | |
330 | #define MURMUR_C4 (0x85ebca6b) | |
331 | #define MURMUR_C5 (0xc2b2ae35) | |
332 | ||
333 | /* This is the main processing body of the algorithm. It operates | |
334 | * on each full 32-bits of input. */ | |
335 | #define MURMUR_DOBLOCK(h1, k1) STMT_START { \ | |
336 | k1 *= MURMUR_C1; \ | |
337 | k1 = ROTL32(k1,15); \ | |
338 | k1 *= MURMUR_C2; \ | |
339 | \ | |
340 | h1 ^= k1; \ | |
341 | h1 = ROTL32(h1,13); \ | |
342 | h1 = h1 * 5 + MURMUR_C3; \ | |
343 | } STMT_END | |
344 | ||
345 | ||
346 | /* Append unaligned bytes to carry, forcing hash churn if we have 4 bytes */ | |
347 | /* cnt=bytes to process, h1=name of h1 var, c=carry, n=bytes in c, ptr/len=payload */ | |
348 | #define MURMUR_DOBYTES(cnt, h1, c, n, ptr, len) STMT_START { \ | |
349 | int MURMUR_DOBYTES_i = cnt; \ | |
350 | while(MURMUR_DOBYTES_i--) { \ | |
351 | c = c>>8 | *ptr++<<24; \ | |
352 | n++; len--; \ | |
353 | if(n==4) { \ | |
354 | MURMUR_DOBLOCK(h1, c); \ | |
355 | n = 0; \ | |
356 | } \ | |
357 | } \ | |
358 | } STMT_END | |
359 | ||
360 | ||
361 | /* now we create the hash function */ | |
362 | PERL_STATIC_INLINE U32 | |
363 | S_perl_hash_murmur3(const unsigned char * const seed, const unsigned char *ptr, STRLEN len) { | |
364 | U32 h1 = *((U32*)seed); | |
365 | U32 k1; | |
366 | U32 carry = 0; | |
367 | ||
368 | const unsigned char *end; | |
369 | int bytes_in_carry = 0; /* bytes in carry */ | |
370 | I32 total_length= len; | |
371 | ||
372 | #if defined(UNALIGNED_SAFE) | |
373 | /* Handle carry: commented out as its only used in incremental mode - it never fires for us | |
374 | int i = (4-n) & 3; | |
375 | if(i && i <= len) { | |
376 | MURMUR_DOBYTES(i, h1, carry, bytes_in_carry, ptr, len); | |
377 | } | |
378 | */ | |
379 | ||
380 | /* This CPU handles unaligned word access */ | |
381 | /* Process 32-bit chunks */ | |
382 | end = ptr + len/4*4; | |
383 | for( ; ptr < end ; ptr+=4) { | |
384 | k1 = U8TO32_LE(ptr); | |
385 | MURMUR_DOBLOCK(h1, k1); | |
386 | } | |
387 | #else | |
388 | /* This CPU does not handle unaligned word access */ | |
389 | ||
390 | /* Consume enough so that the next data byte is word aligned */ | |
c8523631 RB |
391 | STRLEN i = -PTR2IV(ptr) & 3; |
392 | if(i && i <= len) { | |
4d3a042d YO |
393 | MURMUR_DOBYTES(i, h1, carry, bytes_in_carry, ptr, len); |
394 | } | |
395 | ||
396 | /* We're now aligned. Process in aligned blocks. Specialise for each possible carry count */ | |
397 | end = ptr + len/4*4; | |
398 | switch(bytes_in_carry) { /* how many bytes in carry */ | |
399 | case 0: /* c=[----] w=[3210] b=[3210]=w c'=[----] */ | |
400 | for( ; ptr < end ; ptr+=4) { | |
401 | k1 = U8TO32_LE(ptr); | |
402 | MURMUR_DOBLOCK(h1, k1); | |
403 | } | |
404 | break; | |
405 | case 1: /* c=[0---] w=[4321] b=[3210]=c>>24|w<<8 c'=[4---] */ | |
406 | for( ; ptr < end ; ptr+=4) { | |
407 | k1 = carry>>24; | |
408 | carry = U8TO32_LE(ptr); | |
409 | k1 |= carry<<8; | |
410 | MURMUR_DOBLOCK(h1, k1); | |
411 | } | |
412 | break; | |
413 | case 2: /* c=[10--] w=[5432] b=[3210]=c>>16|w<<16 c'=[54--] */ | |
414 | for( ; ptr < end ; ptr+=4) { | |
415 | k1 = carry>>16; | |
416 | carry = U8TO32_LE(ptr); | |
417 | k1 |= carry<<16; | |
418 | MURMUR_DOBLOCK(h1, k1); | |
419 | } | |
420 | break; | |
421 | case 3: /* c=[210-] w=[6543] b=[3210]=c>>8|w<<24 c'=[654-] */ | |
422 | for( ; ptr < end ; ptr+=4) { | |
423 | k1 = carry>>8; | |
424 | carry = U8TO32_LE(ptr); | |
425 | k1 |= carry<<24; | |
426 | MURMUR_DOBLOCK(h1, k1); | |
427 | } | |
428 | } | |
429 | #endif | |
430 | /* Advance over whole 32-bit chunks, possibly leaving 1..3 bytes */ | |
431 | len -= len/4*4; | |
432 | ||
433 | /* Append any remaining bytes into carry */ | |
434 | MURMUR_DOBYTES(len, h1, carry, bytes_in_carry, ptr, len); | |
435 | ||
436 | if (bytes_in_carry) { | |
437 | k1 = carry >> ( 4 - bytes_in_carry ) * 8; | |
438 | k1 *= MURMUR_C1; | |
439 | k1 = ROTL32(k1,15); | |
440 | k1 *= MURMUR_C2; | |
441 | h1 ^= k1; | |
442 | } | |
443 | h1 ^= total_length; | |
444 | ||
445 | /* fmix */ | |
446 | h1 ^= h1 >> 16; | |
447 | h1 *= MURMUR_C4; | |
448 | h1 ^= h1 >> 13; | |
449 | h1 *= MURMUR_C5; | |
450 | h1 ^= h1 >> 16; | |
451 | return h1; | |
452 | } | |
453 | ||
454 | ||
455 | PERL_STATIC_INLINE U32 | |
456 | S_perl_hash_djb2(const unsigned char * const seed, const unsigned char *str, const STRLEN len) { | |
457 | const unsigned char * const end = (const unsigned char *)str + len; | |
458 | U32 hash = *((U32*)seed + len); | |
459 | while (str < end) { | |
460 | hash = ((hash << 5) + hash) + *str++; | |
461 | } | |
462 | return hash; | |
463 | } | |
464 | ||
465 | PERL_STATIC_INLINE U32 | |
466 | S_perl_hash_sdbm(const unsigned char * const seed, const unsigned char *str, const STRLEN len) { | |
467 | const unsigned char * const end = (const unsigned char *)str + len; | |
468 | U32 hash = *((U32*)seed + len); | |
469 | while (str < end) { | |
470 | hash = (hash << 6) + (hash << 16) - hash + *str++; | |
471 | } | |
472 | return hash; | |
473 | } | |
474 | ||
fab3d107 DD |
475 | /* - ONE_AT_A_TIME_HARD is the 5.17+ recommend ONE_AT_A_TIME algorithm |
476 | * - ONE_AT_A_TIME_OLD is the unmodified 5.16 and older algorithm | |
477 | * - ONE_AT_A_TIME is a 5.17+ tweak of ONE_AT_A_TIME_OLD to | |
478 | * prevent strings of only \0 but different lengths from colliding | |
479 | * | |
480 | * Security-wise, from best to worst, | |
481 | * ONE_AT_A_TIME_HARD > ONE_AT_A_TIME > ONE_AT_A_TIME_OLD | |
482 | * There is a big drop-off in security between ONE_AT_A_TIME_HARD and | |
483 | * ONE_AT_A_TIME | |
484 | * */ | |
4d3a042d | 485 | |
b1300a73 | 486 | /* This is the "One-at-a-Time" algorithm by Bob Jenkins |
4d3a042d | 487 | * from requirements by Colin Plumb. |
b1300a73 YO |
488 | * (http://burtleburtle.net/bob/hash/doobs.html) |
489 | * With seed/len tweak. | |
490 | * */ | |
4d3a042d YO |
491 | PERL_STATIC_INLINE U32 |
492 | S_perl_hash_one_at_a_time(const unsigned char * const seed, const unsigned char *str, const STRLEN len) { | |
493 | const unsigned char * const end = (const unsigned char *)str + len; | |
494 | U32 hash = *((U32*)seed) + len; | |
495 | while (str < end) { | |
496 | hash += *str++; | |
497 | hash += (hash << 10); | |
498 | hash ^= (hash >> 6); | |
499 | } | |
500 | hash += (hash << 3); | |
501 | hash ^= (hash >> 11); | |
502 | return (hash + (hash << 15)); | |
503 | } | |
504 | ||
b1300a73 YO |
505 | /* Derived from "One-at-a-Time" algorithm by Bob Jenkins */ |
506 | PERL_STATIC_INLINE U32 | |
507 | S_perl_hash_one_at_a_time_hard(const unsigned char * const seed, const unsigned char *str, const STRLEN len) { | |
508 | const unsigned char * const end = (const unsigned char *)str + len; | |
509 | U32 hash = *((U32*)seed) + len; | |
510 | ||
511 | while (str < end) { | |
512 | hash += (hash << 10); | |
513 | hash ^= (hash >> 6); | |
514 | hash += *str++; | |
515 | } | |
516 | ||
517 | hash += (hash << 10); | |
518 | hash ^= (hash >> 6); | |
519 | hash += seed[4]; | |
520 | ||
521 | hash += (hash << 10); | |
522 | hash ^= (hash >> 6); | |
523 | hash += seed[5]; | |
524 | ||
525 | hash += (hash << 10); | |
526 | hash ^= (hash >> 6); | |
527 | hash += seed[6]; | |
528 | ||
529 | hash += (hash << 10); | |
530 | hash ^= (hash >> 6); | |
531 | hash += seed[7]; | |
532 | ||
533 | hash += (hash << 10); | |
534 | hash ^= (hash >> 6); | |
535 | ||
536 | hash += (hash << 3); | |
537 | hash ^= (hash >> 11); | |
538 | return (hash + (hash << 15)); | |
539 | } | |
540 | ||
4d3a042d YO |
541 | PERL_STATIC_INLINE U32 |
542 | S_perl_hash_old_one_at_a_time(const unsigned char * const seed, const unsigned char *str, const STRLEN len) { | |
543 | const unsigned char * const end = (const unsigned char *)str + len; | |
544 | U32 hash = *((U32*)seed); | |
545 | while (str < end) { | |
546 | hash += *str++; | |
547 | hash += (hash << 10); | |
548 | hash ^= (hash >> 6); | |
549 | } | |
550 | hash += (hash << 3); | |
551 | hash ^= (hash >> 11); | |
552 | return (hash + (hash << 15)); | |
553 | } | |
554 | ||
555 | /* legacy - only mod_perl should be doing this. */ | |
556 | #ifdef PERL_HASH_INTERNAL_ACCESS | |
557 | #define PERL_HASH_INTERNAL(hash,str,len) PERL_HASH(hash,str,len) | |
558 | #endif | |
559 | ||
560 | #endif /*compile once*/ | |
561 | ||
562 | /* | |
563 | * Local variables: | |
564 | * c-indentation-style: bsd | |
565 | * c-basic-offset: 4 | |
566 | * indent-tabs-mode: nil | |
567 | * End: | |
568 | * | |
569 | * ex: set ts=8 sts=4 sw=4 et: | |
570 | */ |