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Diffstat (limited to 'attic/detail/SpookyV2.h')
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diff --git a/attic/detail/SpookyV2.h b/attic/detail/SpookyV2.h new file mode 100644 index 00000000..41d312f8 --- /dev/null +++ b/attic/detail/SpookyV2.h @@ -0,0 +1,302 @@ +#ifndef SPOOKY_HASH_H +#define SPOOKY_HASH_H + +// +// SpookyHash: a 128-bit noncryptographic hash function +// By Bob Jenkins, public domain +// Oct 31 2010: alpha, framework + SpookyHash::Mix appears right +// Oct 31 2011: alpha again, Mix only good to 2^^69 but rest appears right +// Dec 31 2011: beta, improved Mix, tested it for 2-bit deltas +// Feb 2 2012: production, same bits as beta +// Feb 5 2012: adjusted definitions of uint* to be more portable +// Mar 30 2012: 3 bytes/cycle, not 4. Alpha was 4 but wasn't thorough enough. +// August 5 2012: SpookyV2 (different results) +// +// Up to 3 bytes/cycle for long messages. Reasonably fast for short messages. +// All 1 or 2 bit deltas achieve avalanche within 1% bias per output bit. +// +// This was developed for and tested on 64-bit x86-compatible processors. +// It assumes the processor is little-endian. There is a macro +// controlling whether unaligned reads are allowed (by default they are). +// This should be an equally good hash on big-endian machines, but it will +// compute different results on them than on little-endian machines. +// +// Google's CityHash has similar specs to SpookyHash, and CityHash is faster +// on new Intel boxes. MD4 and MD5 also have similar specs, but they are orders +// of magnitude slower. CRCs are two or more times slower, but unlike +// SpookyHash, they have nice math for combining the CRCs of pieces to form +// the CRCs of wholes. There are also cryptographic hashes, but those are even +// slower than MD5. +// + +#include <stddef.h> + +#ifdef _MSC_VER +# define INLINE __forceinline + typedef unsigned __int64 uint64; + typedef unsigned __int32 uint32; + typedef unsigned __int16 uint16; + typedef unsigned __int8 uint8; +#else +# include <stdint.h> +# define INLINE inline + typedef uint64_t uint64; + typedef uint32_t uint32; + typedef uint16_t uint16; + typedef uint8_t uint8; +#endif + + +class SpookyHash +{ +public: + // + // SpookyHash: hash a single message in one call, produce 128-bit output + // + static void Hash128( + const void *message, // message to hash + size_t length, // length of message in bytes + uint64 *hash1, // in/out: in seed 1, out hash value 1 + uint64 *hash2); // in/out: in seed 2, out hash value 2 + + // + // Hash64: hash a single message in one call, return 64-bit output + // + static uint64 Hash64( + const void *message, // message to hash + size_t length, // length of message in bytes + uint64 seed) // seed + { + uint64 hash1 = seed; + Hash128(message, length, &hash1, &seed); + return hash1; + } + + // + // Hash32: hash a single message in one call, produce 32-bit output + // + static uint32 Hash32( + const void *message, // message to hash + size_t length, // length of message in bytes + uint32 seed) // seed + { + uint64 hash1 = seed, hash2 = seed; + Hash128(message, length, &hash1, &hash2); + return (uint32)hash1; + } + + // + // Init: initialize the context of a SpookyHash + // + void Init( + uint64 seed1, // any 64-bit value will do, including 0 + uint64 seed2); // different seeds produce independent hashes + + // + // Update: add a piece of a message to a SpookyHash state + // + void Update( + const void *message, // message fragment + size_t length); // length of message fragment in bytes + + + // + // Final: compute the hash for the current SpookyHash state + // + // This does not modify the state; you can keep updating it afterward + // + // The result is the same as if SpookyHash() had been called with + // all the pieces concatenated into one message. + // + void Final( + uint64 *hash1, // out only: first 64 bits of hash value. + uint64 *hash2); // out only: second 64 bits of hash value. + + // + // left rotate a 64-bit value by k bytes + // + static INLINE uint64 Rot64(uint64 x, int k) + { + return (x << k) | (x >> (64 - k)); + } + + // + // This is used if the input is 96 bytes long or longer. + // + // The internal state is fully overwritten every 96 bytes. + // Every input bit appears to cause at least 128 bits of entropy + // before 96 other bytes are combined, when run forward or backward + // For every input bit, + // Two inputs differing in just that input bit + // Where "differ" means xor or subtraction + // And the base value is random + // When run forward or backwards one Mix + // I tried 3 pairs of each; they all differed by at least 212 bits. + // + static INLINE void Mix( + const uint64 *data, + uint64 &s0, uint64 &s1, uint64 &s2, uint64 &s3, + uint64 &s4, uint64 &s5, uint64 &s6, uint64 &s7, + uint64 &s8, uint64 &s9, uint64 &s10,uint64 &s11) + { + s0 += data[0]; s2 ^= s10; s11 ^= s0; s0 = Rot64(s0,11); s11 += s1; + s1 += data[1]; s3 ^= s11; s0 ^= s1; s1 = Rot64(s1,32); s0 += s2; + s2 += data[2]; s4 ^= s0; s1 ^= s2; s2 = Rot64(s2,43); s1 += s3; + s3 += data[3]; s5 ^= s1; s2 ^= s3; s3 = Rot64(s3,31); s2 += s4; + s4 += data[4]; s6 ^= s2; s3 ^= s4; s4 = Rot64(s4,17); s3 += s5; + s5 += data[5]; s7 ^= s3; s4 ^= s5; s5 = Rot64(s5,28); s4 += s6; + s6 += data[6]; s8 ^= s4; s5 ^= s6; s6 = Rot64(s6,39); s5 += s7; + s7 += data[7]; s9 ^= s5; s6 ^= s7; s7 = Rot64(s7,57); s6 += s8; + s8 += data[8]; s10 ^= s6; s7 ^= s8; s8 = Rot64(s8,55); s7 += s9; + s9 += data[9]; s11 ^= s7; s8 ^= s9; s9 = Rot64(s9,54); s8 += s10; + s10 += data[10]; s0 ^= s8; s9 ^= s10; s10 = Rot64(s10,22); s9 += s11; + s11 += data[11]; s1 ^= s9; s10 ^= s11; s11 = Rot64(s11,46); s10 += s0; + } + + // + // Mix all 12 inputs together so that h0, h1 are a hash of them all. + // + // For two inputs differing in just the input bits + // Where "differ" means xor or subtraction + // And the base value is random, or a counting value starting at that bit + // The final result will have each bit of h0, h1 flip + // For every input bit, + // with probability 50 +- .3% + // For every pair of input bits, + // with probability 50 +- 3% + // + // This does not rely on the last Mix() call having already mixed some. + // Two iterations was almost good enough for a 64-bit result, but a + // 128-bit result is reported, so End() does three iterations. + // + static INLINE void EndPartial( + uint64 &h0, uint64 &h1, uint64 &h2, uint64 &h3, + uint64 &h4, uint64 &h5, uint64 &h6, uint64 &h7, + uint64 &h8, uint64 &h9, uint64 &h10,uint64 &h11) + { + h11+= h1; h2 ^= h11; h1 = Rot64(h1,44); + h0 += h2; h3 ^= h0; h2 = Rot64(h2,15); + h1 += h3; h4 ^= h1; h3 = Rot64(h3,34); + h2 += h4; h5 ^= h2; h4 = Rot64(h4,21); + h3 += h5; h6 ^= h3; h5 = Rot64(h5,38); + h4 += h6; h7 ^= h4; h6 = Rot64(h6,33); + h5 += h7; h8 ^= h5; h7 = Rot64(h7,10); + h6 += h8; h9 ^= h6; h8 = Rot64(h8,13); + h7 += h9; h10^= h7; h9 = Rot64(h9,38); + h8 += h10; h11^= h8; h10= Rot64(h10,53); + h9 += h11; h0 ^= h9; h11= Rot64(h11,42); + h10+= h0; h1 ^= h10; h0 = Rot64(h0,54); + } + + static INLINE void End( + const uint64 *data, + uint64 &h0, uint64 &h1, uint64 &h2, uint64 &h3, + uint64 &h4, uint64 &h5, uint64 &h6, uint64 &h7, + uint64 &h8, uint64 &h9, uint64 &h10,uint64 &h11) + { + h0 += data[0]; h1 += data[1]; h2 += data[2]; h3 += data[3]; + h4 += data[4]; h5 += data[5]; h6 += data[6]; h7 += data[7]; + h8 += data[8]; h9 += data[9]; h10 += data[10]; h11 += data[11]; + EndPartial(h0,h1,h2,h3,h4,h5,h6,h7,h8,h9,h10,h11); + EndPartial(h0,h1,h2,h3,h4,h5,h6,h7,h8,h9,h10,h11); + EndPartial(h0,h1,h2,h3,h4,h5,h6,h7,h8,h9,h10,h11); + } + + // + // The goal is for each bit of the input to expand into 128 bits of + // apparent entropy before it is fully overwritten. + // n trials both set and cleared at least m bits of h0 h1 h2 h3 + // n: 2 m: 29 + // n: 3 m: 46 + // n: 4 m: 57 + // n: 5 m: 107 + // n: 6 m: 146 + // n: 7 m: 152 + // when run forwards or backwards + // for all 1-bit and 2-bit diffs + // with diffs defined by either xor or subtraction + // with a base of all zeros plus a counter, or plus another bit, or random + // + static INLINE void ShortMix(uint64 &h0, uint64 &h1, uint64 &h2, uint64 &h3) + { + h2 = Rot64(h2,50); h2 += h3; h0 ^= h2; + h3 = Rot64(h3,52); h3 += h0; h1 ^= h3; + h0 = Rot64(h0,30); h0 += h1; h2 ^= h0; + h1 = Rot64(h1,41); h1 += h2; h3 ^= h1; + h2 = Rot64(h2,54); h2 += h3; h0 ^= h2; + h3 = Rot64(h3,48); h3 += h0; h1 ^= h3; + h0 = Rot64(h0,38); h0 += h1; h2 ^= h0; + h1 = Rot64(h1,37); h1 += h2; h3 ^= h1; + h2 = Rot64(h2,62); h2 += h3; h0 ^= h2; + h3 = Rot64(h3,34); h3 += h0; h1 ^= h3; + h0 = Rot64(h0,5); h0 += h1; h2 ^= h0; + h1 = Rot64(h1,36); h1 += h2; h3 ^= h1; + } + + // + // Mix all 4 inputs together so that h0, h1 are a hash of them all. + // + // For two inputs differing in just the input bits + // Where "differ" means xor or subtraction + // And the base value is random, or a counting value starting at that bit + // The final result will have each bit of h0, h1 flip + // For every input bit, + // with probability 50 +- .3% (it is probably better than that) + // For every pair of input bits, + // with probability 50 +- .75% (the worst case is approximately that) + // + static INLINE void ShortEnd(uint64 &h0, uint64 &h1, uint64 &h2, uint64 &h3) + { + h3 ^= h2; h2 = Rot64(h2,15); h3 += h2; + h0 ^= h3; h3 = Rot64(h3,52); h0 += h3; + h1 ^= h0; h0 = Rot64(h0,26); h1 += h0; + h2 ^= h1; h1 = Rot64(h1,51); h2 += h1; + h3 ^= h2; h2 = Rot64(h2,28); h3 += h2; + h0 ^= h3; h3 = Rot64(h3,9); h0 += h3; + h1 ^= h0; h0 = Rot64(h0,47); h1 += h0; + h2 ^= h1; h1 = Rot64(h1,54); h2 += h1; + h3 ^= h2; h2 = Rot64(h2,32); h3 += h2; + h0 ^= h3; h3 = Rot64(h3,25); h0 += h3; + h1 ^= h0; h0 = Rot64(h0,63); h1 += h0; + } + +private: + + // + // Short is used for messages under 192 bytes in length + // Short has a low startup cost, the normal mode is good for long + // keys, the cost crossover is at about 192 bytes. The two modes were + // held to the same quality bar. + // + static void Short( + const void *message, // message (array of bytes, not necessarily aligned) + size_t length, // length of message (in bytes) + uint64 *hash1, // in/out: in the seed, out the hash value + uint64 *hash2); // in/out: in the seed, out the hash value + + // number of uint64's in internal state + static const size_t sc_numVars = 12; + + // size of the internal state + static const size_t sc_blockSize = sc_numVars*8; + + // size of buffer of unhashed data, in bytes + static const size_t sc_bufSize = 2*sc_blockSize; + + // + // sc_const: a constant which: + // * is not zero + // * is odd + // * is a not-very-regular mix of 1's and 0's + // * does not need any other special mathematical properties + // + static const uint64 sc_const = 0xdeadbeefdeadbeefULL; + + uint64 m_data[2*sc_numVars]; // unhashed data, for partial messages + uint64 m_state[sc_numVars]; // internal state of the hash + size_t m_length; // total length of the input so far + uint8 m_remainder; // length of unhashed data stashed in m_data +}; + + +#endif |