[perl5.git] / hv_func.h

/* hash a key
 *--------------------------------------------------------------------------------------
 * The "hash seed" feature was added in Perl 5.8.1 to perturb the results
 * to avoid "algorithmic complexity attacks".
 *
 * If USE_HASH_SEED is defined, hash randomisation is done by default
 * If USE_HASH_SEED_EXPLICIT is defined, hash randomisation is done
 * only if the environment variable PERL_HASH_SEED is set.
 * (see also perl.c:perl_parse() and S_init_tls_and_interp() and util.c:get_hash_seed())
 */

#ifndef PERL_SEEN_HV_FUNC_H /* compile once */
#define PERL_SEEN_HV_FUNC_H

#if !( 0 \
        || defined(PERL_HASH_FUNC_SIPHASH) \
        || defined(PERL_HASH_FUNC_SDBM) \
        || defined(PERL_HASH_FUNC_DJB2) \
        || defined(PERL_HASH_FUNC_SUPERFAST) \
        || defined(PERL_HASH_FUNC_MURMUR3) \
        || defined(PERL_HASH_FUNC_ONE_AT_A_TIME) \
        || defined(PERL_HASH_FUNC_ONE_AT_A_TIME_HARD) \
        || defined(PERL_HASH_FUNC_ONE_AT_A_TIME_OLD) \
    )
#define PERL_HASH_FUNC_ONE_AT_A_TIME_HARD
#endif

#if defined(PERL_HASH_FUNC_SIPHASH)
#   define PERL_HASH_FUNC "SIPHASH_2_4"
#   define PERL_HASH_SEED_BYTES 16
#   define PERL_HASH_WITH_SEED(seed,hash,str,len) (hash)= S_perl_hash_siphash_2_4((seed),(U8*)(str),(len))
#elif defined(PERL_HASH_FUNC_SUPERFAST)
#   define PERL_HASH_FUNC "SUPERFAST"
#   define PERL_HASH_SEED_BYTES 4
#   define PERL_HASH_WITH_SEED(seed,hash,str,len) (hash)= S_perl_hash_superfast((seed),(U8*)(str),(len))
#elif defined(PERL_HASH_FUNC_MURMUR3)
#   define PERL_HASH_FUNC "MURMUR3"
#   define PERL_HASH_SEED_BYTES 4
#   define PERL_HASH_WITH_SEED(seed,hash,str,len) (hash)= S_perl_hash_murmur3((seed),(U8*)(str),(len))
#elif defined(PERL_HASH_FUNC_DJB2)
#   define PERL_HASH_FUNC "DJB2"
#   define PERL_HASH_SEED_BYTES 4
#   define PERL_HASH_WITH_SEED(seed,hash,str,len) (hash)= S_perl_hash_djb2((seed),(U8*)(str),(len))
#elif defined(PERL_HASH_FUNC_SDBM)
#   define PERL_HASH_FUNC "SDBM"
#   define PERL_HASH_SEED_BYTES 4
#   define PERL_HASH_WITH_SEED(seed,hash,str,len) (hash)= S_perl_hash_sdbm((seed),(U8*)(str),(len))
#elif defined(PERL_HASH_FUNC_ONE_AT_A_TIME_HARD)
#   define PERL_HASH_FUNC "ONE_AT_A_TIME_HARD"
#   define PERL_HASH_SEED_BYTES 8
#   define PERL_HASH_WITH_SEED(seed,hash,str,len) (hash)= S_perl_hash_one_at_a_time_hard((seed),(U8*)(str),(len))
#elif defined(PERL_HASH_FUNC_ONE_AT_A_TIME)
#   define PERL_HASH_FUNC "ONE_AT_A_TIME"
#   define PERL_HASH_SEED_BYTES 4
#   define PERL_HASH_WITH_SEED(seed,hash,str,len) (hash)= S_perl_hash_one_at_a_time((seed),(U8*)(str),(len))
#elif defined(PERL_HASH_FUNC_ONE_AT_A_TIME_OLD)
#   define PERL_HASH_FUNC "ONE_AT_A_TIME_OLD"
#   define PERL_HASH_SEED_BYTES 4
#   define PERL_HASH_WITH_SEED(seed,hash,str,len) (hash)= S_perl_hash_old_one_at_a_time((seed),(U8*)(str),(len))
#endif

#ifndef PERL_HASH_WITH_SEED
#error "No hash function defined!"
#endif
#ifndef PERL_HASH_SEED_BYTES
#error "PERL_HASH_SEED_BYTES not defined"
#endif
#ifndef PERL_HASH_FUNC
#error "PERL_HASH_FUNC not defined"
#endif

#ifndef PERL_HASH_SEED
#   if defined(USE_HASH_SEED) || defined(USE_HASH_SEED_EXPLICIT)
#       define PERL_HASH_SEED PL_hash_seed
#   elif PERL_HASH_SEED_BYTES == 4
#       define PERL_HASH_SEED "PeRl"
#   elif PERL_HASH_SEED_BYTES == 16
#       define PERL_HASH_SEED "PeRlHaShhAcKpErl"
#   else
#       error "No PERL_HASH_SEED definition for " PERL_HASH_FUNC
#   endif
#endif

#define PERL_HASH(hash,str,len) PERL_HASH_WITH_SEED(PERL_HASH_SEED,hash,str,len)

/*-----------------------------------------------------------------------------
 * Endianess, misalignment capabilities and util macros
 *
 * The following 3 macros are defined in this section. The other macros defined
 * are only needed to help derive these 3.
 *
 * U8TO32_LE(x)   Read a little endian unsigned 32-bit int
 * UNALIGNED_SAFE   Defined if READ_UINT32 works on non-word boundaries
 * ROTL32(x,r)      Rotate x left by r bits
 */

#if (defined(__GNUC__) && defined(__i386__)) || defined(__WATCOMC__) \
  || defined(_MSC_VER) || defined (__TURBOC__)
#define U8TO16_LE(d) (*((const U16 *) (d)))
#endif

#if !defined (U8TO16_LE)
#define U8TO16_LE(d) ((((const U8 *)(d))[1] << 8)\
                      +((const U8 *)(d))[0])
#endif


/* Now find best way we can to READ_UINT32 */
#if (BYTEORDER == 0x1234 || BYTEORDER == 0x12345678) && U32SIZE == 4
  /* CPU endian matches murmurhash algorithm, so read 32-bit word directly */
  #define U8TO32_LE(ptr)   (*((U32*)(ptr)))
#elif BYTEORDER == 0x4321 || BYTEORDER == 0x87654321
  /* TODO: Add additional cases below where a compiler provided bswap32 is available */
  #if defined(__GNUC__) && (__GNUC__>4 || (__GNUC__==4 && __GNUC_MINOR__>=3))
    #define U8TO32_LE(ptr)   (__builtin_bswap32(*((U32*)(ptr))))
  #else
    /* Without a known fast bswap32 we're just as well off doing this */
    #define U8TO32_LE(ptr)   (ptr[0]|ptr[1]<<8|ptr[2]<<16|ptr[3]<<24)
    #define UNALIGNED_SAFE
  #endif
#else
  /* Unknown endianess so last resort is to read individual bytes */
  #define U8TO32_LE(ptr)   (ptr[0]|ptr[1]<<8|ptr[2]<<16|ptr[3]<<24)
  /* Since we're not doing word-reads we can skip the messing about with realignment */
  #define UNALIGNED_SAFE
#endif

#ifdef HAS_QUAD
#ifndef U64TYPE
/* This probably isn't going to work, but failing with a compiler error due to
   lack of uint64_t is no worse than failing right now with an #error.  */
#define U64TYPE uint64_t
#endif
#endif

/* Find best way to ROTL32/ROTL64 */
#if defined(_MSC_VER)
  #include <stdlib.h>  /* Microsoft put _rotl declaration in here */
  #define ROTL32(x,r)  _rotl(x,r)
  #ifdef HAS_QUAD
    #define ROTL64(x,r)  _rotl64(x,r)
  #endif
#else
  /* gcc recognises this code and generates a rotate instruction for CPUs with one */
  #define ROTL32(x,r)  (((U32)x << r) | ((U32)x >> (32 - r)))
  #ifdef HAS_QUAD
    #define ROTL64(x,r)  (((U64TYPE)x << r) | ((U64TYPE)x >> (64 - r)))
  #endif
#endif


#ifdef UV_IS_QUAD
#define ROTL_UV(x,r) ROTL64(x,r)
#else
#define ROTL_UV(x,r) ROTL32(x,r)
#endif

/* This is SipHash by Jean-Philippe Aumasson and Daniel J. Bernstein.
 * The authors claim it is relatively secure compared to the alternatives
 * and that performance wise it is a suitable hash for languages like Perl.
 * See:
 *
 * https://www.131002.net/siphash/
 *
 * This implementation seems to perform slightly slower than one-at-a-time for
 * short keys, but degrades slower for longer keys. Murmur Hash outperforms it
 * regardless of keys size.
 *
 * It is 64 bit only.
 */

#ifdef HAS_QUAD

#define U8TO64_LE(p) \
  (((U64TYPE)((p)[0])      ) | \
   ((U64TYPE)((p)[1]) <<  8) | \
   ((U64TYPE)((p)[2]) << 16) | \
   ((U64TYPE)((p)[3]) << 24) | \
   ((U64TYPE)((p)[4]) << 32) | \
   ((U64TYPE)((p)[5]) << 40) | \
   ((U64TYPE)((p)[6]) << 48) | \
   ((U64TYPE)((p)[7]) << 56))

#define SIPROUND            \
  do {              \
    v0 += v1; v1=ROTL64(v1,13); v1 ^= v0; v0=ROTL64(v0,32); \
    v2 += v3; v3=ROTL64(v3,16); v3 ^= v2;     \
    v0 += v3; v3=ROTL64(v3,21); v3 ^= v0;     \
    v2 += v1; v1=ROTL64(v1,17); v1 ^= v2; v2=ROTL64(v2,32); \
  } while(0)

/* SipHash-2-4 */

PERL_STATIC_INLINE U32
S_perl_hash_siphash_2_4(const unsigned char * const seed, const unsigned char *in, const STRLEN inlen) {
  /* "somepseudorandomlygeneratedbytes" */
  U64TYPE v0 = UINT64_C(0x736f6d6570736575);
  U64TYPE v1 = UINT64_C(0x646f72616e646f6d);
  U64TYPE v2 = UINT64_C(0x6c7967656e657261);
  U64TYPE v3 = UINT64_C(0x7465646279746573);

  U64TYPE b;
  U64TYPE k0 = ((U64TYPE*)seed)[0];
  U64TYPE k1 = ((U64TYPE*)seed)[1];
  U64TYPE m;
  const int left = inlen & 7;
  const U8 *end = in + inlen - left;

  b = ( ( U64TYPE )(inlen) ) << 56;
  v3 ^= k1;
  v2 ^= k0;
  v1 ^= k1;
  v0 ^= k0;

  for ( ; in != end; in += 8 )
  {
    m = U8TO64_LE( in );
    v3 ^= m;
    SIPROUND;
    SIPROUND;
    v0 ^= m;
  }

  switch( left )
  {
  case 7: b |= ( ( U64TYPE )in[ 6] )  << 48;
  case 6: b |= ( ( U64TYPE )in[ 5] )  << 40;
  case 5: b |= ( ( U64TYPE )in[ 4] )  << 32;
  case 4: b |= ( ( U64TYPE )in[ 3] )  << 24;
  case 3: b |= ( ( U64TYPE )in[ 2] )  << 16;
  case 2: b |= ( ( U64TYPE )in[ 1] )  <<  8;
  case 1: b |= ( ( U64TYPE )in[ 0] ); break;
  case 0: break;
  }

  v3 ^= b;
  SIPROUND;
  SIPROUND;
  v0 ^= b;

  v2 ^= 0xff;
  SIPROUND;
  SIPROUND;
  SIPROUND;
  SIPROUND;
  b = v0 ^ v1 ^ v2  ^ v3;
  return (U32)(b & U32_MAX);
}
#endif /* defined(HAS_QUAD) */

/* FYI: This is the "Super-Fast" algorithm mentioned by Bob Jenkins in
 * (http://burtleburtle.net/bob/hash/doobs.html)
 * It is by Paul Hsieh (c) 2004 and is analysed here
 * http://www.azillionmonkeys.com/qed/hash.html
 * license terms are here:
 * http://www.azillionmonkeys.com/qed/weblicense.html
 */


PERL_STATIC_INLINE U32
S_perl_hash_superfast(const unsigned char * const seed, const unsigned char *str, STRLEN len) {
    U32 hash = *((U32*)seed) + len;
    U32 tmp;
    int rem= len & 3;
    len >>= 2;

    for (;len > 0; len--) {
        hash  += U8TO16_LE (str);
        tmp    = (U8TO16_LE (str+2) << 11) ^ hash;
        hash   = (hash << 16) ^ tmp;
        str   += 2 * sizeof (U16);
        hash  += hash >> 11;
    }

    /* Handle end cases */
    switch (rem) { \
        case 3: hash += U8TO16_LE (str);
                hash ^= hash << 16;
                hash ^= str[sizeof (U16)] << 18;
                hash += hash >> 11;
                break;
        case 2: hash += U8TO16_LE (str);
                hash ^= hash << 11;
                hash += hash >> 17;
                break;
        case 1: hash += *str;
                hash ^= hash << 10;
                hash += hash >> 1;
    }
    /* Force "avalanching" of final 127 bits */
    hash ^= hash << 3;
    hash += hash >> 5;
    hash ^= hash << 4;
    hash += hash >> 17;
    hash ^= hash << 25;
    return (hash + (hash >> 6));
}


/*-----------------------------------------------------------------------------
 * MurmurHash3 was written by Austin Appleby, and is placed in the public
 * domain.
 *
 * This implementation was originally written by Shane Day, and is also public domain,
 * and was modified to function as a macro similar to other perl hash functions by
 * Yves Orton.
 *
 * This is a portable ANSI C implementation of MurmurHash3_x86_32 (Murmur3A)
 * with support for progressive processing.
 *
 * If you want to understand the MurmurHash algorithm you would be much better
 * off reading the original source. Just point your browser at:
 * http://code.google.com/p/smhasher/source/browse/trunk/MurmurHash3.cpp
 *
 * How does it work?
 *
 * We can only process entire 32 bit chunks of input, except for the very end
 * that may be shorter.
 *
 * To handle endianess I simply use a macro that reads a U32 and define
 * that macro to be a direct read on little endian machines, a read and swap
 * on big endian machines, or a byte-by-byte read if the endianess is unknown.
 */


/*-----------------------------------------------------------------------------
 * Core murmurhash algorithm macros */

#define MURMUR_C1  (0xcc9e2d51)
#define MURMUR_C2  (0x1b873593)
#define MURMUR_C3  (0xe6546b64)
#define MURMUR_C4  (0x85ebca6b)
#define MURMUR_C5  (0xc2b2ae35)

/* This is the main processing body of the algorithm. It operates
 * on each full 32-bits of input. */
#define MURMUR_DOBLOCK(h1, k1) STMT_START { \
    k1 *= MURMUR_C1; \
    k1 = ROTL32(k1,15); \
    k1 *= MURMUR_C2; \
    \
    h1 ^= k1; \
    h1 = ROTL32(h1,13); \
    h1 = h1 * 5 + MURMUR_C3; \
} STMT_END


/* Append unaligned bytes to carry, forcing hash churn if we have 4 bytes */
/* cnt=bytes to process, h1=name of h1 var, c=carry, n=bytes in c, ptr/len=payload */
#define MURMUR_DOBYTES(cnt, h1, c, n, ptr, len) STMT_START { \
    int MURMUR_DOBYTES_i = cnt; \
    while(MURMUR_DOBYTES_i--) { \
        c = c>>8 | *ptr++<<24; \
        n++; len--; \
        if(n==4) { \
            MURMUR_DOBLOCK(h1, c); \
            n = 0; \
        } \
    } \
} STMT_END


/* now we create the hash function */
PERL_STATIC_INLINE U32
S_perl_hash_murmur3(const unsigned char * const seed, const unsigned char *ptr, STRLEN len) {
    U32 h1 = *((U32*)seed);
    U32 k1;
    U32 carry = 0;

    const unsigned char *end;
    int bytes_in_carry = 0; /* bytes in carry */
    I32 total_length= len;

#if defined(UNALIGNED_SAFE)
    /* Handle carry: commented out as its only used in incremental mode - it never fires for us
    int i = (4-n) & 3;
    if(i && i <= len) {
      MURMUR_DOBYTES(i, h1, carry, bytes_in_carry, ptr, len);
    }
    */

    /* This CPU handles unaligned word access */
    /* Process 32-bit chunks */
    end = ptr + len/4*4;
    for( ; ptr < end ; ptr+=4) {
        k1 = U8TO32_LE(ptr);
        MURMUR_DOBLOCK(h1, k1);
    }
#else
    /* This CPU does not handle unaligned word access */

    /* Consume enough so that the next data byte is word aligned */
    STRLEN i = -PTR2IV(ptr) & 3;
    if(i && i <= len) {
      MURMUR_DOBYTES(i, h1, carry, bytes_in_carry, ptr, len);
    }

    /* We're now aligned. Process in aligned blocks. Specialise for each possible carry count */
    end = ptr + len/4*4;
    switch(bytes_in_carry) { /* how many bytes in carry */
        case 0: /* c=[----]  w=[3210]  b=[3210]=w            c'=[----] */
        for( ; ptr < end ; ptr+=4) {
            k1 = U8TO32_LE(ptr);
            MURMUR_DOBLOCK(h1, k1);
        }
        break;
        case 1: /* c=[0---]  w=[4321]  b=[3210]=c>>24|w<<8   c'=[4---] */
        for( ; ptr < end ; ptr+=4) {
            k1 = carry>>24;
            carry = U8TO32_LE(ptr);
            k1 |= carry<<8;
            MURMUR_DOBLOCK(h1, k1);
        }
        break;
        case 2: /* c=[10--]  w=[5432]  b=[3210]=c>>16|w<<16  c'=[54--] */
        for( ; ptr < end ; ptr+=4) {
            k1 = carry>>16;
            carry = U8TO32_LE(ptr);
            k1 |= carry<<16;
            MURMUR_DOBLOCK(h1, k1);
        }
        break;
        case 3: /* c=[210-]  w=[6543]  b=[3210]=c>>8|w<<24   c'=[654-] */
        for( ; ptr < end ; ptr+=4) {
            k1 = carry>>8;
            carry = U8TO32_LE(ptr);
            k1 |= carry<<24;
            MURMUR_DOBLOCK(h1, k1);
        }
    }
#endif
    /* Advance over whole 32-bit chunks, possibly leaving 1..3 bytes */
    len -= len/4*4;

    /* Append any remaining bytes into carry */
    MURMUR_DOBYTES(len, h1, carry, bytes_in_carry, ptr, len);

    if (bytes_in_carry) {
        k1 = carry >> ( 4 - bytes_in_carry ) * 8;
        k1 *= MURMUR_C1;
        k1 = ROTL32(k1,15);
        k1 *= MURMUR_C2;
        h1 ^= k1;
    }
    h1 ^= total_length;

    /* fmix */
    h1 ^= h1 >> 16;
    h1 *= MURMUR_C4;
    h1 ^= h1 >> 13;
    h1 *= MURMUR_C5;
    h1 ^= h1 >> 16;
    return h1;
}


PERL_STATIC_INLINE U32
S_perl_hash_djb2(const unsigned char * const seed, const unsigned char *str, const STRLEN len) {
    const unsigned char * const end = (const unsigned char *)str + len;
    U32 hash = *((U32*)seed) + len;
    while (str < end) {
        hash = ((hash << 5) + hash) + *str++;
    }
    return hash;
}

PERL_STATIC_INLINE U32
S_perl_hash_sdbm(const unsigned char * const seed, const unsigned char *str, const STRLEN len) {
    const unsigned char * const end = (const unsigned char *)str + len;
    U32 hash = *((U32*)seed) + len;
    while (str < end) {
        hash = (hash << 6) + (hash << 16) - hash + *str++;
    }
    return hash;
}

/* - ONE_AT_A_TIME_HARD is the 5.17+ recommend ONE_AT_A_TIME algorithm
 * - ONE_AT_A_TIME_OLD is the unmodified 5.16 and older algorithm
 * - ONE_AT_A_TIME is a 5.17+ tweak of ONE_AT_A_TIME_OLD to
 *   prevent strings of only \0 but different lengths from colliding
 *
 * Security-wise, from best to worst,
 * ONE_AT_A_TIME_HARD > ONE_AT_A_TIME > ONE_AT_A_TIME_OLD
 * There is a big drop-off in security between ONE_AT_A_TIME_HARD and
 * ONE_AT_A_TIME
 * */

/* This is the "One-at-a-Time" algorithm by Bob Jenkins
 * from requirements by Colin Plumb.
 * (http://burtleburtle.net/bob/hash/doobs.html)
 * With seed/len tweak.
 * */
PERL_STATIC_INLINE U32
S_perl_hash_one_at_a_time(const unsigned char * const seed, const unsigned char *str, const STRLEN len) {
    const unsigned char * const end = (const unsigned char *)str + len;
    U32 hash = *((U32*)seed) + len;
    while (str < end) {
        hash += *str++;
        hash += (hash << 10);
        hash ^= (hash >> 6);
    }
    hash += (hash << 3);
    hash ^= (hash >> 11);
    return (hash + (hash << 15));
}

/* Derived from "One-at-a-Time" algorithm by Bob Jenkins */
PERL_STATIC_INLINE U32
S_perl_hash_one_at_a_time_hard(const unsigned char * const seed, const unsigned char *str, const STRLEN len) {
    const unsigned char * const end = (const unsigned char *)str + len;
    U32 hash = *((U32*)seed) + len;
    
    while (str < end) {
        hash += (hash << 10);
        hash ^= (hash >> 6);
        hash += *str++;
    }
    
    hash += (hash << 10);
    hash ^= (hash >> 6);
    hash += seed[4];
    
    hash += (hash << 10);
    hash ^= (hash >> 6);
    hash += seed[5];
    
    hash += (hash << 10);
    hash ^= (hash >> 6);
    hash += seed[6];
    
    hash += (hash << 10);
    hash ^= (hash >> 6);
    hash += seed[7];
    
    hash += (hash << 10);
    hash ^= (hash >> 6);

    hash += (hash << 3);
    hash ^= (hash >> 11);
    return (hash + (hash << 15));
}

PERL_STATIC_INLINE U32
S_perl_hash_old_one_at_a_time(const unsigned char * const seed, const unsigned char *str, const STRLEN len) {
    const unsigned char * const end = (const unsigned char *)str + len;
    U32 hash = *((U32*)seed);
    while (str < end) {
        hash += *str++;
        hash += (hash << 10);
        hash ^= (hash >> 6);
    }
    hash += (hash << 3);
    hash ^= (hash >> 11);
    return (hash + (hash << 15));
}

/* legacy - only mod_perl should be doing this.  */
#ifdef PERL_HASH_INTERNAL_ACCESS
#define PERL_HASH_INTERNAL(hash,str,len) PERL_HASH(hash,str,len)
#endif

#endif /*compile once*/

/*
 * Local variables:
 * c-indentation-style: bsd
 * c-basic-offset: 4
 * indent-tabs-mode: nil
 * End:
 *
 * ex: set ts=8 sts=4 sw=4 et:
 */
Commit	Line	Data
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) \
4d3a042d YO	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
3d53a8ea	31	# define PERL_HASH_WITH_SEED(seed,hash,str,len) (hash)= S_perl_hash_siphash_2_4((seed),(U8*)(str),(len))
4d3a042d YO	32	#elif defined(PERL_HASH_FUNC_SUPERFAST)
	33	# define PERL_HASH_FUNC "SUPERFAST"
	34	# define PERL_HASH_SEED_BYTES 4
3d53a8ea	35	# define PERL_HASH_WITH_SEED(seed,hash,str,len) (hash)= S_perl_hash_superfast((seed),(U8*)(str),(len))
4d3a042d YO	36	#elif defined(PERL_HASH_FUNC_MURMUR3)
	37	# define PERL_HASH_FUNC "MURMUR3"
	38	# define PERL_HASH_SEED_BYTES 4
3d53a8ea	39	# define PERL_HASH_WITH_SEED(seed,hash,str,len) (hash)= S_perl_hash_murmur3((seed),(U8*)(str),(len))
4d3a042d YO	40	#elif defined(PERL_HASH_FUNC_DJB2)
	41	# define PERL_HASH_FUNC "DJB2"
	42	# define PERL_HASH_SEED_BYTES 4
3d53a8ea	43	# define PERL_HASH_WITH_SEED(seed,hash,str,len) (hash)= S_perl_hash_djb2((seed),(U8*)(str),(len))
4d3a042d YO	44	#elif defined(PERL_HASH_FUNC_SDBM)
	45	# define PERL_HASH_FUNC "SDBM"
	46	# define PERL_HASH_SEED_BYTES 4
3d53a8ea	47	# define PERL_HASH_WITH_SEED(seed,hash,str,len) (hash)= S_perl_hash_sdbm((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
3d53a8ea	51	# define PERL_HASH_WITH_SEED(seed,hash,str,len) (hash)= S_perl_hash_one_at_a_time_hard((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
3d53a8ea	55	# define PERL_HASH_WITH_SEED(seed,hash,str,len) (hash)= S_perl_hash_one_at_a_time((seed),(U8*)(str),(len))
4d3a042d YO	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
3d53a8ea	59	# define PERL_HASH_WITH_SEED(seed,hash,str,len) (hash)= S_perl_hash_old_one_at_a_time((seed),(U8*)(str),(len))
4d3a042d YO	60	#endif
4d3a042d YO	61
3d53a8ea	62	#ifndef PERL_HASH_WITH_SEED
4d3a042d YO	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
3d53a8ea YO	84	#define PERL_HASH(hash,str,len) PERL_HASH_WITH_SEED(PERL_HASH_SEED,hash,str,len)
3d53a8ea YO	85
4d3a042d YO	86	/*-----------------------------------------------------------------------------
	87	* Endianess, misalignment capabilities and util macros
	88	*
	89	* The following 3 macros are defined in this section. The other macros defined
	90	* are only needed to help derive these 3.
	91	*
	92	* U8TO32_LE(x) Read a little endian unsigned 32-bit int
	93	* UNALIGNED_SAFE Defined if READ_UINT32 works on non-word boundaries
	94	* ROTL32(x,r) Rotate x left by r bits
	95	*/
	96
	97	#if (defined(__GNUC__) && defined(__i386__)) \|\| defined(__WATCOMC__) \
0a35fd8a	98	\|\| defined(_MSC_VER) \|\| defined (__TURBOC__)
4d3a042d YO	99	#define U8TO16_LE(d) (((const U16 ) (d)))
	100	#endif
	101
	102	#if !defined (U8TO16_LE)
	103	#define U8TO16_LE(d) ((((const U8 *)(d))[1] << 8)\
	104	+((const U8 *)(d))[0])
	105	#endif
	106
	107
	108	/* Now find best way we can to READ_UINT32 */
	109	#if (BYTEORDER == 0x1234 \|\| BYTEORDER == 0x12345678) && U32SIZE == 4
	110	/* CPU endian matches murmurhash algorithm, so read 32-bit word directly */
	111	#define U8TO32_LE(ptr) (((U32)(ptr)))
	112	#elif BYTEORDER == 0x4321 \|\| BYTEORDER == 0x87654321
	113	/* TODO: Add additional cases below where a compiler provided bswap32 is available */
	114	#if defined(__GNUC__) && (__GNUC__>4 \|\| (__GNUC__==4 && __GNUC_MINOR__>=3))
	115	#define U8TO32_LE(ptr) (__builtin_bswap32(((U32)(ptr))))
	116	#else
	117	/* Without a known fast bswap32 we're just as well off doing this */
	118	#define U8TO32_LE(ptr) (ptr[0]\|ptr[1]<<8\|ptr[2]<<16\|ptr[3]<<24)
	119	#define UNALIGNED_SAFE
	120	#endif
	121	#else
	122	/* Unknown endianess so last resort is to read individual bytes */
	123	#define U8TO32_LE(ptr) (ptr[0]\|ptr[1]<<8\|ptr[2]<<16\|ptr[3]<<24)
	124	/* Since we're not doing word-reads we can skip the messing about with realignment */
	125	#define UNALIGNED_SAFE
	126	#endif
	127
b716320d YO	128	#ifdef HAS_QUAD
	129	#ifndef U64TYPE
	130	/* This probably isn't going to work, but failing with a compiler error due to
	131	lack of uint64_t is no worse than failing right now with an #error. */
	132	#define U64TYPE uint64_t
	133	#endif
	134	#endif
	135
	136	/* Find best way to ROTL32/ROTL64 */
4d3a042d YO	137	#if defined(_MSC_VER)
	138	#include <stdlib.h> /* Microsoft put _rotl declaration in here */
	139	#define ROTL32(x,r) _rotl(x,r)
b716320d YO	140	#ifdef HAS_QUAD
	141	#define ROTL64(x,r) _rotl64(x,r)
	142	#endif
4d3a042d YO	143	#else
	144	/* gcc recognises this code and generates a rotate instruction for CPUs with one */
	145	#define ROTL32(x,r) (((U32)x << r) \| ((U32)x >> (32 - r)))
b716320d YO	146	#ifdef HAS_QUAD
	147	#define ROTL64(x,r) (((U64TYPE)x << r) \| ((U64TYPE)x >> (64 - r)))
	148	#endif
4d3a042d YO	149	#endif
	150
	151
b716320d YO	152	#ifdef UV_IS_QUAD
	153	#define ROTL_UV(x,r) ROTL64(x,r)
	154	#else
	155	#define ROTL_UV(x,r) ROTL32(x,r)
	156	#endif
	157
4d3a042d YO	158	/* This is SipHash by Jean-Philippe Aumasson and Daniel J. Bernstein.
	159	* The authors claim it is relatively secure compared to the alternatives
	160	* and that performance wise it is a suitable hash for languages like Perl.
	161	* See:
	162	*
	163	* https://www.131002.net/siphash/
	164	*
	165	* This implementation seems to perform slightly slower than one-at-a-time for
	166	* short keys, but degrades slower for longer keys. Murmur Hash outperforms it
	167	* regardless of keys size.
	168	*
	169	* It is 64 bit only.
	170	*/
	171
	172	#ifdef HAS_QUAD
	173
4d3a042d YO	174	#define U8TO64_LE(p) \
	175	(((U64TYPE)((p)[0]) ) \| \
	176	((U64TYPE)((p)[1]) << 8) \| \
	177	((U64TYPE)((p)[2]) << 16) \| \
	178	((U64TYPE)((p)[3]) << 24) \| \
	179	((U64TYPE)((p)[4]) << 32) \| \
	180	((U64TYPE)((p)[5]) << 40) \| \
	181	((U64TYPE)((p)[6]) << 48) \| \
	182	((U64TYPE)((p)[7]) << 56))
	183
	184	#define SIPROUND \
	185	do { \
	186	v0 += v1; v1=ROTL64(v1,13); v1 ^= v0; v0=ROTL64(v0,32); \
	187	v2 += v3; v3=ROTL64(v3,16); v3 ^= v2; \
	188	v0 += v3; v3=ROTL64(v3,21); v3 ^= v0; \
	189	v2 += v1; v1=ROTL64(v1,17); v1 ^= v2; v2=ROTL64(v2,32); \
	190	} while(0)
	191
	192	/* SipHash-2-4 */
	193
	194	PERL_STATIC_INLINE U32
	195	S_perl_hash_siphash_2_4(const unsigned char * const seed, const unsigned char *in, const STRLEN inlen) {
	196	/* "somepseudorandomlygeneratedbytes" */
f4e3fd26 JH	197	U64TYPE v0 = UINT64_C(0x736f6d6570736575);
	198	U64TYPE v1 = UINT64_C(0x646f72616e646f6d);
	199	U64TYPE v2 = UINT64_C(0x6c7967656e657261);
	200	U64TYPE v3 = UINT64_C(0x7465646279746573);
4d3a042d YO	201
	202	U64TYPE b;
	203	U64TYPE k0 = ((U64TYPE*)seed)[0];
	204	U64TYPE k1 = ((U64TYPE*)seed)[1];
	205	U64TYPE m;
	206	const int left = inlen & 7;
	207	const U8 *end = in + inlen - left;
	208
	209	b = ( ( U64TYPE )(inlen) ) << 56;
	210	v3 ^= k1;
	211	v2 ^= k0;
	212	v1 ^= k1;
	213	v0 ^= k0;
	214
	215	for ( ; in != end; in += 8 )
	216	{
	217	m = U8TO64_LE( in );
	218	v3 ^= m;
	219	SIPROUND;
	220	SIPROUND;
	221	v0 ^= m;
	222	}
	223
	224	switch( left )
	225	{
	226	case 7: b \|= ( ( U64TYPE )in[ 6] ) << 48;
	227	case 6: b \|= ( ( U64TYPE )in[ 5] ) << 40;
	228	case 5: b \|= ( ( U64TYPE )in[ 4] ) << 32;
	229	case 4: b \|= ( ( U64TYPE )in[ 3] ) << 24;
	230	case 3: b \|= ( ( U64TYPE )in[ 2] ) << 16;
	231	case 2: b \|= ( ( U64TYPE )in[ 1] ) << 8;
	232	case 1: b \|= ( ( U64TYPE )in[ 0] ); break;
	233	case 0: break;
	234	}
	235
	236	v3 ^= b;
	237	SIPROUND;
	238	SIPROUND;
	239	v0 ^= b;
	240
	241	v2 ^= 0xff;
	242	SIPROUND;
	243	SIPROUND;
	244	SIPROUND;
	245	SIPROUND;
	246	b = v0 ^ v1 ^ v2 ^ v3;
	247	return (U32)(b & U32_MAX);
	248	}
	249	#endif /* defined(HAS_QUAD) */
	250
	251	/* FYI: This is the "Super-Fast" algorithm mentioned by Bob Jenkins in
	252	* (http://burtleburtle.net/bob/hash/doobs.html)
	253	* It is by Paul Hsieh (c) 2004 and is analysed here
	254	* http://www.azillionmonkeys.com/qed/hash.html
	255	* license terms are here:
	256	* http://www.azillionmonkeys.com/qed/weblicense.html
	257	*/
	258
	259
	260	PERL_STATIC_INLINE U32
	261	S_perl_hash_superfast(const unsigned char * const seed, const unsigned char *str, STRLEN len) {
	262	U32 hash = ((U32)seed) + len;
	263	U32 tmp;
	264	int rem= len & 3;
265	len >>= 2;
266
267	for (;len > 0; len--) {
268	hash += U8TO16_LE (str);
269	tmp = (U8TO16_LE (str+2) << 11) ^ hash;
270	hash = (hash << 16) ^ tmp;
271	str += 2 * sizeof (U16);
272	hash += hash >> 11;
273	}
274
275	/* Handle end cases */
276	switch (rem) { \
277	case 3: hash += U8TO16_LE (str);
278	hash ^= hash << 16;
279	hash ^= str[sizeof (U16)] << 18;
280	hash += hash >> 11;
281	break;
282	case 2: hash += U8TO16_LE (str);
283	hash ^= hash << 11;
284	hash += hash >> 17;
285	break;
286	case 1: hash += *str;
287	hash ^= hash << 10;
288	hash += hash >> 1;
289	}
290	/* Force "avalanching" of final 127 bits */
291	hash ^= hash << 3;
292	hash += hash >> 5;
293	hash ^= hash << 4;
294	hash += hash >> 17;
295	hash ^= hash << 25;
296	return (hash + (hash >> 6));
297	}
298
299
300	/*-----------------------------------------------------------------------------
301	* MurmurHash3 was written by Austin Appleby, and is placed in the public
302	* domain.
303	*
304	* This implementation was originally written by Shane Day, and is also public domain,
305	* and was modified to function as a macro similar to other perl hash functions by
306	* Yves Orton.
307	*
308	* This is a portable ANSI C implementation of MurmurHash3_x86_32 (Murmur3A)
309	* with support for progressive processing.
310	*
311	* If you want to understand the MurmurHash algorithm you would be much better
312	* off reading the original source. Just point your browser at:
313	* http://code.google.com/p/smhasher/source/browse/trunk/MurmurHash3.cpp
314	*
315	* How does it work?
316	*
317	* We can only process entire 32 bit chunks of input, except for the very end
318	* that may be shorter.
319	*
320	* To handle endianess I simply use a macro that reads a U32 and define
321	* that macro to be a direct read on little endian machines, a read and swap
322	* on big endian machines, or a byte-by-byte read if the endianess is unknown.
323	*/
324
325
326	/*-----------------------------------------------------------------------------
327	* Core murmurhash algorithm macros */
328
329	#define MURMUR_C1 (0xcc9e2d51)
330	#define MURMUR_C2 (0x1b873593)
331	#define MURMUR_C3 (0xe6546b64)
332	#define MURMUR_C4 (0x85ebca6b)
333	#define MURMUR_C5 (0xc2b2ae35)
334
335	/* This is the main processing body of the algorithm. It operates
336	* on each full 32-bits of input. */
337	#define MURMUR_DOBLOCK(h1, k1) STMT_START { \
338	k1 *= MURMUR_C1; \
339	k1 = ROTL32(k1,15); \
340	k1 *= MURMUR_C2; \
341	\
342	h1 ^= k1; \
343	h1 = ROTL32(h1,13); \
344	h1 = h1 * 5 + MURMUR_C3; \
345	} STMT_END
346
347
348	/* Append unaligned bytes to carry, forcing hash churn if we have 4 bytes */
349	/* cnt=bytes to process, h1=name of h1 var, c=carry, n=bytes in c, ptr/len=payload */
350	#define MURMUR_DOBYTES(cnt, h1, c, n, ptr, len) STMT_START { \
351	int MURMUR_DOBYTES_i = cnt; \
352	while(MURMUR_DOBYTES_i--) { \
353	c = c>>8 \| *ptr++<<24; \
354	n++; len--; \
355	if(n==4) { \
356	MURMUR_DOBLOCK(h1, c); \
357	n = 0; \
358	} \
359	} \
360	} STMT_END
361
362
363	/* now we create the hash function */
364	PERL_STATIC_INLINE U32
365	S_perl_hash_murmur3(const unsigned char * const seed, const unsigned char *ptr, STRLEN len) {
366	U32 h1 = ((U32)seed);
367	U32 k1;
368	U32 carry = 0;
369
370	const unsigned char *end;
371	int bytes_in_carry = 0; /* bytes in carry */
372	I32 total_length= len;
373
374	#if defined(UNALIGNED_SAFE)
375	/* Handle carry: commented out as its only used in incremental mode - it never fires for us
376	int i = (4-n) & 3;
377	if(i && i <= len) {
378	MURMUR_DOBYTES(i, h1, carry, bytes_in_carry, ptr, len);
379	}
380	*/
381
382	/* This CPU handles unaligned word access */
383	/* Process 32-bit chunks */
384	end = ptr + len/4*4;
385	for( ; ptr < end ; ptr+=4) {
386	k1 = U8TO32_LE(ptr);
387	MURMUR_DOBLOCK(h1, k1);
388	}
389	#else
390	/* This CPU does not handle unaligned word access */
391
392	/* Consume enough so that the next data byte is word aligned */
c8523631 RB	393	STRLEN i = -PTR2IV(ptr) & 3;
c8523631 RB	394	if(i && i <= len) {
4d3a042d YO	395	MURMUR_DOBYTES(i, h1, carry, bytes_in_carry, ptr, len);
	396	}
	397
	398	/* We're now aligned. Process in aligned blocks. Specialise for each possible carry count */
	399	end = ptr + len/4*4;
	400	switch(bytes_in_carry) { /* how many bytes in carry */
	401	case 0: /* c=[----] w=[3210] b=[3210]=w c'=[----] */
	402	for( ; ptr < end ; ptr+=4) {
	403	k1 = U8TO32_LE(ptr);
	404	MURMUR_DOBLOCK(h1, k1);
	405	}
	406	break;
	407	case 1: /* c=[0---] w=[4321] b=[3210]=c>>24\|w<<8 c'=[4---] */
	408	for( ; ptr < end ; ptr+=4) {
	409	k1 = carry>>24;
	410	carry = U8TO32_LE(ptr);
	411	k1 \|= carry<<8;
	412	MURMUR_DOBLOCK(h1, k1);
	413	}
	414	break;
	415	case 2: /* c=[10--] w=[5432] b=[3210]=c>>16\|w<<16 c'=[54--] */
	416	for( ; ptr < end ; ptr+=4) {
	417	k1 = carry>>16;
	418	carry = U8TO32_LE(ptr);
	419	k1 \|= carry<<16;
	420	MURMUR_DOBLOCK(h1, k1);
	421	}
	422	break;
	423	case 3: /* c=[210-] w=[6543] b=[3210]=c>>8\|w<<24 c'=[654-] */
	424	for( ; ptr < end ; ptr+=4) {
	425	k1 = carry>>8;
	426	carry = U8TO32_LE(ptr);
	427	k1 \|= carry<<24;
	428	MURMUR_DOBLOCK(h1, k1);
	429	}
	430	}
	431	#endif
	432	/* Advance over whole 32-bit chunks, possibly leaving 1..3 bytes */
	433	len -= len/4*4;
	434
	435	/* Append any remaining bytes into carry */
	436	MURMUR_DOBYTES(len, h1, carry, bytes_in_carry, ptr, len);
	437
	438	if (bytes_in_carry) {
	439	k1 = carry >> ( 4 - bytes_in_carry ) * 8;
	440	k1 *= MURMUR_C1;
	441	k1 = ROTL32(k1,15);
	442	k1 *= MURMUR_C2;
	443	h1 ^= k1;
	444	}
	445	h1 ^= total_length;
	446
	447	/* fmix */
	448	h1 ^= h1 >> 16;
	449	h1 *= MURMUR_C4;
	450	h1 ^= h1 >> 13;
	451	h1 *= MURMUR_C5;
	452	h1 ^= h1 >> 16;
	453	return h1;
	454	}
	455
	456
	457	PERL_STATIC_INLINE U32
	458	S_perl_hash_djb2(const unsigned char * const seed, const unsigned char *str, const STRLEN len) {
459	const unsigned char * const end = (const unsigned char *)str + len;
54e07e2b	460	U32 hash = ((U32)seed) + len;
4d3a042d YO	461	while (str < end) {
	462	hash = ((hash << 5) + hash) + *str++;
	463	}
	464	return hash;
	465	}
	466
	467	PERL_STATIC_INLINE U32
	468	S_perl_hash_sdbm(const unsigned char * const seed, const unsigned char *str, const STRLEN len) {
	469	const unsigned char * const end = (const unsigned char *)str + len;
54e07e2b	470	U32 hash = ((U32)seed) + len;
4d3a042d YO	471	while (str < end) {
	472	hash = (hash << 6) + (hash << 16) - hash + *str++;
	473	}
	474	return hash;
	475	}
	476
fab3d107 DD	477	/* - ONE_AT_A_TIME_HARD is the 5.17+ recommend ONE_AT_A_TIME algorithm
	478	* - ONE_AT_A_TIME_OLD is the unmodified 5.16 and older algorithm
	479	* - ONE_AT_A_TIME is a 5.17+ tweak of ONE_AT_A_TIME_OLD to
	480	* prevent strings of only \0 but different lengths from colliding
	481	*
	482	* Security-wise, from best to worst,
	483	* ONE_AT_A_TIME_HARD > ONE_AT_A_TIME > ONE_AT_A_TIME_OLD
	484	* There is a big drop-off in security between ONE_AT_A_TIME_HARD and
	485	* ONE_AT_A_TIME
	486	* */
4d3a042d	487
b1300a73	488	/* This is the "One-at-a-Time" algorithm by Bob Jenkins
4d3a042d	489	* from requirements by Colin Plumb.
b1300a73 YO	490	* (http://burtleburtle.net/bob/hash/doobs.html)
	491	* With seed/len tweak.
	492	* */
4d3a042d YO	493	PERL_STATIC_INLINE U32
	494	S_perl_hash_one_at_a_time(const unsigned char * const seed, const unsigned char *str, const STRLEN len) {
	495	const unsigned char * const end = (const unsigned char *)str + len;
	496	U32 hash = ((U32)seed) + len;
	497	while (str < end) {
	498	hash += *str++;
	499	hash += (hash << 10);
	500	hash ^= (hash >> 6);
	501	}
	502	hash += (hash << 3);
	503	hash ^= (hash >> 11);
	504	return (hash + (hash << 15));
	505	}
	506
b1300a73 YO	507	/* Derived from "One-at-a-Time" algorithm by Bob Jenkins */
	508	PERL_STATIC_INLINE U32
	509	S_perl_hash_one_at_a_time_hard(const unsigned char * const seed, const unsigned char *str, const STRLEN len) {
	510	const unsigned char * const end = (const unsigned char *)str + len;
	511	U32 hash = ((U32)seed) + len;
	512
	513	while (str < end) {
	514	hash += (hash << 10);
	515	hash ^= (hash >> 6);
	516	hash += *str++;
	517	}
	518
	519	hash += (hash << 10);
	520	hash ^= (hash >> 6);
	521	hash += seed[4];
	522
	523	hash += (hash << 10);
	524	hash ^= (hash >> 6);
	525	hash += seed[5];
	526
	527	hash += (hash << 10);
	528	hash ^= (hash >> 6);
	529	hash += seed[6];
	530
	531	hash += (hash << 10);
	532	hash ^= (hash >> 6);
	533	hash += seed[7];
	534
	535	hash += (hash << 10);
	536	hash ^= (hash >> 6);
	537
	538	hash += (hash << 3);
	539	hash ^= (hash >> 11);
	540	return (hash + (hash << 15));
	541	}
	542
4d3a042d YO	543	PERL_STATIC_INLINE U32
	544	S_perl_hash_old_one_at_a_time(const unsigned char * const seed, const unsigned char *str, const STRLEN len) {
	545	const unsigned char * const end = (const unsigned char *)str + len;
	546	U32 hash = ((U32)seed);
	547	while (str < end) {
	548	hash += *str++;
	549	hash += (hash << 10);
	550	hash ^= (hash >> 6);
	551	}
	552	hash += (hash << 3);
	553	hash ^= (hash >> 11);
	554	return (hash + (hash << 15));
	555	}
	556
	557	/* legacy - only mod_perl should be doing this. */
	558	#ifdef PERL_HASH_INTERNAL_ACCESS
	559	#define PERL_HASH_INTERNAL(hash,str,len) PERL_HASH(hash,str,len)
	560	#endif
	561
	562	#endif /compile once/
	563
	564	/*
	565	* Local variables:
	566	* c-indentation-style: bsd
	567	* c-basic-offset: 4
	568	* indent-tabs-mode: nil
	569	* End:
	570	*
	571	* ex: set ts=8 sts=4 sw=4 et:
	572	*/