2 *--------------------------------------------------------------------------------------
3 * The "hash seed" feature was added in Perl 5.8.1 to perturb the results
4 * to avoid "algorithmic complexity attacks".
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())
12 #ifndef PERL_SEEN_HV_FUNC_H /* compile once */
13 #define PERL_SEEN_HV_FUNC_H
14 #define PERL_HASH_FUNC_ONE_AT_A_TIME_HARD
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) \
22 || defined(PERL_HASH_FUNC_ONE_AT_A_TIME_HARD) \
23 || defined(PERL_HASH_FUNC_ONE_AT_A_TIME_OLD) \
26 #define PERL_HASH_FUNC_SIPHASH
28 #define PERL_HASH_FUNC_ONE_AT_A_TIME_HARD
32 #if defined(PERL_HASH_FUNC_SIPHASH)
33 # define PERL_HASH_FUNC "SIPHASH_2_4"
34 # define PERL_HASH_SEED_BYTES 16
35 # define PERL_HASH(hash,str,len) (hash)= S_perl_hash_siphash_2_4(PERL_HASH_SEED,(U8*)(str),(len))
36 #elif defined(PERL_HASH_FUNC_SUPERFAST)
37 # define PERL_HASH_FUNC "SUPERFAST"
38 # define PERL_HASH_SEED_BYTES 4
39 # define PERL_HASH(hash,str,len) (hash)= S_perl_hash_superfast(PERL_HASH_SEED,(U8*)(str),(len))
40 #elif defined(PERL_HASH_FUNC_MURMUR3)
41 # define PERL_HASH_FUNC "MURMUR3"
42 # define PERL_HASH_SEED_BYTES 4
43 # define PERL_HASH(hash,str,len) (hash)= S_perl_hash_murmur3(PERL_HASH_SEED,(U8*)(str),(len))
44 #elif defined(PERL_HASH_FUNC_DJB2)
45 # define PERL_HASH_FUNC "DJB2"
46 # define PERL_HASH_SEED_BYTES 4
47 # define PERL_HASH(hash,str,len) (hash)= S_perl_hash_djb2(PERL_HASH_SEED,(U8*)(str),(len))
48 #elif defined(PERL_HASH_FUNC_SDBM)
49 # define PERL_HASH_FUNC "SDBM"
50 # define PERL_HASH_SEED_BYTES 4
51 # define PERL_HASH(hash,str,len) (hash)= S_perl_hash_sdbm(PERL_HASH_SEED,(U8*)(str),(len))
52 #elif defined(PERL_HASH_FUNC_ONE_AT_A_TIME_HARD)
53 # define PERL_HASH_FUNC "ONE_AT_A_TIME_HARD"
54 # define PERL_HASH_SEED_BYTES 8
55 # define PERL_HASH(hash,str,len) (hash)= S_perl_hash_one_at_a_time_hard(PERL_HASH_SEED,(U8*)(str),(len))
56 #elif defined(PERL_HASH_FUNC_ONE_AT_A_TIME)
57 # define PERL_HASH_FUNC "ONE_AT_A_TIME"
58 # define PERL_HASH_SEED_BYTES 4
59 # define PERL_HASH(hash,str,len) (hash)= S_perl_hash_one_at_a_time(PERL_HASH_SEED,(U8*)(str),(len))
60 #elif defined(PERL_HASH_FUNC_ONE_AT_A_TIME_OLD)
61 # define PERL_HASH_FUNC "ONE_AT_A_TIME_OLD"
62 # define PERL_HASH_SEED_BYTES 4
63 # define PERL_HASH(hash,str,len) (hash)= S_perl_hash_old_one_at_a_time(PERL_HASH_SEED,(U8*)(str),(len))
67 #error "No hash function defined!"
69 #ifndef PERL_HASH_SEED_BYTES
70 #error "PERL_HASH_SEED_BYTES not defined"
72 #ifndef PERL_HASH_FUNC
73 #error "PERL_HASH_FUNC not defined"
76 #ifndef PERL_HASH_SEED
77 # if defined(USE_HASH_SEED) || defined(USE_HASH_SEED_EXPLICIT)
78 # define PERL_HASH_SEED PL_hash_seed
79 # elif PERL_HASH_SEED_BYTES == 4
80 # define PERL_HASH_SEED "PeRl"
81 # elif PERL_HASH_SEED_BYTES == 16
82 # define PERL_HASH_SEED "PeRlHaShhAcKpErl"
84 # error "No PERL_HASH_SEED definition for " PERL_HASH_FUNC
88 /*-----------------------------------------------------------------------------
89 * Endianess, misalignment capabilities and util macros
91 * The following 3 macros are defined in this section. The other macros defined
92 * are only needed to help derive these 3.
94 * U8TO32_LE(x) Read a little endian unsigned 32-bit int
95 * UNALIGNED_SAFE Defined if READ_UINT32 works on non-word boundaries
96 * ROTL32(x,r) Rotate x left by r bits
99 #if (defined(__GNUC__) && defined(__i386__)) || defined(__WATCOMC__) \
100 || defined(_MSC_VER) || defined (__BORLANDC__) || defined (__TURBOC__)
101 #define U8TO16_LE(d) (*((const U16 *) (d)))
104 #if !defined (U8TO16_LE)
105 #define U8TO16_LE(d) ((((const U8 *)(d))[1] << 8)\
106 +((const U8 *)(d))[0])
110 /* Now find best way we can to READ_UINT32 */
111 #if (BYTEORDER == 0x1234 || BYTEORDER == 0x12345678) && U32SIZE == 4
112 /* CPU endian matches murmurhash algorithm, so read 32-bit word directly */
113 #define U8TO32_LE(ptr) (*((U32*)(ptr)))
114 #elif BYTEORDER == 0x4321 || BYTEORDER == 0x87654321
115 /* TODO: Add additional cases below where a compiler provided bswap32 is available */
116 #if defined(__GNUC__) && (__GNUC__>4 || (__GNUC__==4 && __GNUC_MINOR__>=3))
117 #define U8TO32_LE(ptr) (__builtin_bswap32(*((U32*)(ptr))))
119 /* Without a known fast bswap32 we're just as well off doing this */
120 #define U8TO32_LE(ptr) (ptr[0]|ptr[1]<<8|ptr[2]<<16|ptr[3]<<24)
121 #define UNALIGNED_SAFE
124 /* Unknown endianess so last resort is to read individual bytes */
125 #define U8TO32_LE(ptr) (ptr[0]|ptr[1]<<8|ptr[2]<<16|ptr[3]<<24)
126 /* Since we're not doing word-reads we can skip the messing about with realignment */
127 #define UNALIGNED_SAFE
132 /* This probably isn't going to work, but failing with a compiler error due to
133 lack of uint64_t is no worse than failing right now with an #error. */
134 #define U64TYPE uint64_t
138 /* Find best way to ROTL32/ROTL64 */
139 #if defined(_MSC_VER)
140 #include <stdlib.h> /* Microsoft put _rotl declaration in here */
141 #define ROTL32(x,r) _rotl(x,r)
143 #define ROTL64(x,r) _rotl64(x,r)
146 /* gcc recognises this code and generates a rotate instruction for CPUs with one */
147 #define ROTL32(x,r) (((U32)x << r) | ((U32)x >> (32 - r)))
149 #define ROTL64(x,r) (((U64TYPE)x << r) | ((U64TYPE)x >> (64 - r)))
155 #define ROTL_UV(x,r) ROTL64(x,r)
157 #define ROTL_UV(x,r) ROTL32(x,r)
160 /* This is SipHash by Jean-Philippe Aumasson and Daniel J. Bernstein.
161 * The authors claim it is relatively secure compared to the alternatives
162 * and that performance wise it is a suitable hash for languages like Perl.
165 * https://www.131002.net/siphash/
167 * This implementation seems to perform slightly slower than one-at-a-time for
168 * short keys, but degrades slower for longer keys. Murmur Hash outperforms it
169 * regardless of keys size.
176 #define U8TO64_LE(p) \
177 (((U64TYPE)((p)[0]) ) | \
178 ((U64TYPE)((p)[1]) << 8) | \
179 ((U64TYPE)((p)[2]) << 16) | \
180 ((U64TYPE)((p)[3]) << 24) | \
181 ((U64TYPE)((p)[4]) << 32) | \
182 ((U64TYPE)((p)[5]) << 40) | \
183 ((U64TYPE)((p)[6]) << 48) | \
184 ((U64TYPE)((p)[7]) << 56))
188 v0 += v1; v1=ROTL64(v1,13); v1 ^= v0; v0=ROTL64(v0,32); \
189 v2 += v3; v3=ROTL64(v3,16); v3 ^= v2; \
190 v0 += v3; v3=ROTL64(v3,21); v3 ^= v0; \
191 v2 += v1; v1=ROTL64(v1,17); v1 ^= v2; v2=ROTL64(v2,32); \
196 PERL_STATIC_INLINE U32
197 S_perl_hash_siphash_2_4(const unsigned char * const seed, const unsigned char *in, const STRLEN inlen) {
198 /* "somepseudorandomlygeneratedbytes" */
199 U64TYPE v0 = 0x736f6d6570736575ULL;
200 U64TYPE v1 = 0x646f72616e646f6dULL;
201 U64TYPE v2 = 0x6c7967656e657261ULL;
202 U64TYPE v3 = 0x7465646279746573ULL;
205 U64TYPE k0 = ((U64TYPE*)seed)[0];
206 U64TYPE k1 = ((U64TYPE*)seed)[1];
208 const int left = inlen & 7;
209 const U8 *end = in + inlen - left;
211 b = ( ( U64TYPE )(inlen) ) << 56;
217 for ( ; in != end; in += 8 )
228 case 7: b |= ( ( U64TYPE )in[ 6] ) << 48;
229 case 6: b |= ( ( U64TYPE )in[ 5] ) << 40;
230 case 5: b |= ( ( U64TYPE )in[ 4] ) << 32;
231 case 4: b |= ( ( U64TYPE )in[ 3] ) << 24;
232 case 3: b |= ( ( U64TYPE )in[ 2] ) << 16;
233 case 2: b |= ( ( U64TYPE )in[ 1] ) << 8;
234 case 1: b |= ( ( U64TYPE )in[ 0] ); break;
248 b = v0 ^ v1 ^ v2 ^ v3;
249 return (U32)(b & U32_MAX);
251 #endif /* defined(HAS_QUAD) */
253 /* FYI: This is the "Super-Fast" algorithm mentioned by Bob Jenkins in
254 * (http://burtleburtle.net/bob/hash/doobs.html)
255 * It is by Paul Hsieh (c) 2004 and is analysed here
256 * http://www.azillionmonkeys.com/qed/hash.html
257 * license terms are here:
258 * http://www.azillionmonkeys.com/qed/weblicense.html
262 PERL_STATIC_INLINE U32
263 S_perl_hash_superfast(const unsigned char * const seed, const unsigned char *str, STRLEN len) {
264 U32 hash = *((U32*)seed) + len;
269 for (;len > 0; len--) {
270 hash += U8TO16_LE (str);
271 tmp = (U8TO16_LE (str+2) << 11) ^ hash;
272 hash = (hash << 16) ^ tmp;
273 str += 2 * sizeof (U16);
277 /* Handle end cases */
279 case 3: hash += U8TO16_LE (str);
281 hash ^= str[sizeof (U16)] << 18;
284 case 2: hash += U8TO16_LE (str);
288 case 1: hash += *str;
292 /* Force "avalanching" of final 127 bits */
298 return (hash + (hash >> 6));
302 /*-----------------------------------------------------------------------------
303 * MurmurHash3 was written by Austin Appleby, and is placed in the public
306 * This implementation was originally written by Shane Day, and is also public domain,
307 * and was modified to function as a macro similar to other perl hash functions by
310 * This is a portable ANSI C implementation of MurmurHash3_x86_32 (Murmur3A)
311 * with support for progressive processing.
313 * If you want to understand the MurmurHash algorithm you would be much better
314 * off reading the original source. Just point your browser at:
315 * http://code.google.com/p/smhasher/source/browse/trunk/MurmurHash3.cpp
319 * We can only process entire 32 bit chunks of input, except for the very end
320 * that may be shorter.
322 * To handle endianess I simply use a macro that reads a U32 and define
323 * that macro to be a direct read on little endian machines, a read and swap
324 * on big endian machines, or a byte-by-byte read if the endianess is unknown.
328 /*-----------------------------------------------------------------------------
329 * Core murmurhash algorithm macros */
331 #define MURMUR_C1 (0xcc9e2d51)
332 #define MURMUR_C2 (0x1b873593)
333 #define MURMUR_C3 (0xe6546b64)
334 #define MURMUR_C4 (0x85ebca6b)
335 #define MURMUR_C5 (0xc2b2ae35)
337 /* This is the main processing body of the algorithm. It operates
338 * on each full 32-bits of input. */
339 #define MURMUR_DOBLOCK(h1, k1) STMT_START { \
341 k1 = ROTL32(k1,15); \
345 h1 = ROTL32(h1,13); \
346 h1 = h1 * 5 + MURMUR_C3; \
350 /* Append unaligned bytes to carry, forcing hash churn if we have 4 bytes */
351 /* cnt=bytes to process, h1=name of h1 var, c=carry, n=bytes in c, ptr/len=payload */
352 #define MURMUR_DOBYTES(cnt, h1, c, n, ptr, len) STMT_START { \
353 int MURMUR_DOBYTES_i = cnt; \
354 while(MURMUR_DOBYTES_i--) { \
355 c = c>>8 | *ptr++<<24; \
358 MURMUR_DOBLOCK(h1, c); \
365 /* now we create the hash function */
366 PERL_STATIC_INLINE U32
367 S_perl_hash_murmur3(const unsigned char * const seed, const unsigned char *ptr, STRLEN len) {
368 U32 h1 = *((U32*)seed);
372 const unsigned char *end;
373 int bytes_in_carry = 0; /* bytes in carry */
374 I32 total_length= len;
376 #if defined(UNALIGNED_SAFE)
377 /* Handle carry: commented out as its only used in incremental mode - it never fires for us
380 MURMUR_DOBYTES(i, h1, carry, bytes_in_carry, ptr, len);
384 /* This CPU handles unaligned word access */
385 /* Process 32-bit chunks */
387 for( ; ptr < end ; ptr+=4) {
389 MURMUR_DOBLOCK(h1, k1);
392 /* This CPU does not handle unaligned word access */
394 /* Consume enough so that the next data byte is word aligned */
395 int i = -(long)ptr & 3;
396 if(i && (STRLEN)i <= len) {
397 MURMUR_DOBYTES(i, h1, carry, bytes_in_carry, ptr, len);
400 /* We're now aligned. Process in aligned blocks. Specialise for each possible carry count */
402 switch(bytes_in_carry) { /* how many bytes in carry */
403 case 0: /* c=[----] w=[3210] b=[3210]=w c'=[----] */
404 for( ; ptr < end ; ptr+=4) {
406 MURMUR_DOBLOCK(h1, k1);
409 case 1: /* c=[0---] w=[4321] b=[3210]=c>>24|w<<8 c'=[4---] */
410 for( ; ptr < end ; ptr+=4) {
412 carry = U8TO32_LE(ptr);
414 MURMUR_DOBLOCK(h1, k1);
417 case 2: /* c=[10--] w=[5432] b=[3210]=c>>16|w<<16 c'=[54--] */
418 for( ; ptr < end ; ptr+=4) {
420 carry = U8TO32_LE(ptr);
422 MURMUR_DOBLOCK(h1, k1);
425 case 3: /* c=[210-] w=[6543] b=[3210]=c>>8|w<<24 c'=[654-] */
426 for( ; ptr < end ; ptr+=4) {
428 carry = U8TO32_LE(ptr);
430 MURMUR_DOBLOCK(h1, k1);
434 /* Advance over whole 32-bit chunks, possibly leaving 1..3 bytes */
437 /* Append any remaining bytes into carry */
438 MURMUR_DOBYTES(len, h1, carry, bytes_in_carry, ptr, len);
440 if (bytes_in_carry) {
441 k1 = carry >> ( 4 - bytes_in_carry ) * 8;
459 PERL_STATIC_INLINE U32
460 S_perl_hash_djb2(const unsigned char * const seed, const unsigned char *str, const STRLEN len) {
461 const unsigned char * const end = (const unsigned char *)str + len;
462 U32 hash = *((U32*)seed + len);
464 hash = ((hash << 5) + hash) + *str++;
469 PERL_STATIC_INLINE U32
470 S_perl_hash_sdbm(const unsigned char * const seed, const unsigned char *str, const STRLEN len) {
471 const unsigned char * const end = (const unsigned char *)str + len;
472 U32 hash = *((U32*)seed + len);
474 hash = (hash << 6) + (hash << 16) - hash + *str++;
480 /* This is the "One-at-a-Time" algorithm by Bob Jenkins
481 * from requirements by Colin Plumb.
482 * (http://burtleburtle.net/bob/hash/doobs.html)
483 * With seed/len tweak.
485 PERL_STATIC_INLINE U32
486 S_perl_hash_one_at_a_time(const unsigned char * const seed, const unsigned char *str, const STRLEN len) {
487 const unsigned char * const end = (const unsigned char *)str + len;
488 U32 hash = *((U32*)seed) + len;
491 hash += (hash << 10);
495 hash ^= (hash >> 11);
496 return (hash + (hash << 15));
499 /* Derived from "One-at-a-Time" algorithm by Bob Jenkins */
500 PERL_STATIC_INLINE U32
501 S_perl_hash_one_at_a_time_hard(const unsigned char * const seed, const unsigned char *str, const STRLEN len) {
502 const unsigned char * const end = (const unsigned char *)str + len;
503 U32 hash = *((U32*)seed) + len;
506 hash += (hash << 10);
511 hash += (hash << 10);
515 hash += (hash << 10);
519 hash += (hash << 10);
523 hash += (hash << 10);
527 hash += (hash << 10);
531 hash ^= (hash >> 11);
532 return (hash + (hash << 15));
535 PERL_STATIC_INLINE U32
536 S_perl_hash_old_one_at_a_time(const unsigned char * const seed, const unsigned char *str, const STRLEN len) {
537 const unsigned char * const end = (const unsigned char *)str + len;
538 U32 hash = *((U32*)seed);
541 hash += (hash << 10);
545 hash ^= (hash >> 11);
546 return (hash + (hash << 15));
549 /* legacy - only mod_perl should be doing this. */
550 #ifdef PERL_HASH_INTERNAL_ACCESS
551 #define PERL_HASH_INTERNAL(hash,str,len) PERL_HASH(hash,str,len)
554 #endif /*compile once*/
558 * c-indentation-style: bsd
560 * indent-tabs-mode: nil
563 * ex: set ts=8 sts=4 sw=4 et: