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src/SpookyV2.h  view on Meta::CPAN

  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