// // Copyright 2021 Pixar // // Licensed under the Apache License, Version 2.0 (the "Apache License") // with the following modification; you may not use this file except in // compliance with the Apache License and the following modification to it: // Section 6. Trademarks. is deleted and replaced with: // // 6. Trademarks. This License does not grant permission to use the trade // names, trademarks, service marks, or product names of the Licensor // and its affiliates, except as required to comply with Section 4(c) of // the License and to reproduce the content of the NOTICE file. // // You may obtain a copy of the Apache License at // // http://www.apache.org/licenses/LICENSE-2.0 // // Unless required by applicable law or agreed to in writing, software // distributed under the Apache License with the above modification is // distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY // KIND, either express or implied. See the Apache License for the specific // language governing permissions and limitations under the Apache License. // // // Functions for hashing to 32- and 64-bit integers. These are the same // functions used in USD (pxr/base/arch/hash.*) under similar conditions. // #include "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 #include // Local typedefs to match the original code: typedef uint64_t uint64; typedef uint32_t uint32; typedef uint16_t uint16; typedef uint8_t uint8; namespace { 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; } #ifdef OPENSUBDIV3_BFR_HASH_INCLUDE_UNUSED_FUNCTIONS // // 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. #endif // // 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 = 0xdeadbeefdeadbeefLL; 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 }; #define ALLOW_UNALIGNED_READS 1 // // short hash ... it could be used on any message, // but it's used by Spooky just for short messages. // void SpookyHash::Short( const void *message, size_t length, uint64 *hash1, uint64 *hash2) { uint64 buf[2*sc_numVars]; union { const uint8 *p8; uint32 *p32; uint64 *p64; size_t i; } u; u.p8 = (const uint8 *)message; if (!ALLOW_UNALIGNED_READS && (u.i & 0x7)) { memcpy(buf, message, length); u.p64 = buf; } size_t remainder = length%32; uint64 a=*hash1; uint64 b=*hash2; uint64 c=sc_const; uint64 d=sc_const; if (length > 15) { const uint64 *end = u.p64 + (length/32)*4; // handle all complete sets of 32 bytes for (; u.p64 < end; u.p64 += 4) { c += u.p64[0]; d += u.p64[1]; ShortMix(a,b,c,d); a += u.p64[2]; b += u.p64[3]; } //Handle the case of 16+ remaining bytes. if (remainder >= 16) { c += u.p64[0]; d += u.p64[1]; ShortMix(a,b,c,d); u.p64 += 2; remainder -= 16; } } // Handle the last 0..15 bytes, and its length d += ((uint64)length) << 56; switch (remainder) { case 15: d += ((uint64)u.p8[14]) << 48; // FALLTHRU case 14: d += ((uint64)u.p8[13]) << 40; // FALLTHRU case 13: d += ((uint64)u.p8[12]) << 32; // FALLTHRU case 12: d += u.p32[2]; c += u.p64[0]; break; case 11: d += ((uint64)u.p8[10]) << 16; // FALLTHRU case 10: d += ((uint64)u.p8[9]) << 8; // FALLTHRU case 9: d += (uint64)u.p8[8]; // FALLTHRU case 8: c += u.p64[0]; break; case 7: c += ((uint64)u.p8[6]) << 48; // FALLTHRU case 6: c += ((uint64)u.p8[5]) << 40; // FALLTHRU case 5: c += ((uint64)u.p8[4]) << 32; // FALLTHRU case 4: c += u.p32[0]; break; case 3: c += ((uint64)u.p8[2]) << 16; // FALLTHRU case 2: c += ((uint64)u.p8[1]) << 8; // FALLTHRU case 1: c += (uint64)u.p8[0]; break; case 0: c += sc_const; d += sc_const; } ShortEnd(a,b,c,d); *hash1 = a; *hash2 = b; } // do the whole hash in one call void SpookyHash::Hash128( const void *message, size_t length, uint64 *hash1, uint64 *hash2) { if (length < sc_bufSize) { Short(message, length, hash1, hash2); return; } uint64 h0,h1,h2,h3,h4,h5,h6,h7,h8,h9,h10,h11; uint64 buf[sc_numVars]; uint64 *end; union { const uint8 *p8; uint64 *p64; size_t i; } u; size_t remainder; h0=h3=h6=h9 = *hash1; h1=h4=h7=h10 = *hash2; h2=h5=h8=h11 = sc_const; u.p8 = (const uint8 *)message; end = u.p64 + (length/sc_blockSize)*sc_numVars; // handle all whole sc_blockSize blocks of bytes if (ALLOW_UNALIGNED_READS || ((u.i & 0x7) == 0)) { while (u.p64 < end) { Mix(u.p64, h0,h1,h2,h3,h4,h5,h6,h7,h8,h9,h10,h11); u.p64 += sc_numVars; } } else { while (u.p64 < end) { memcpy(buf, u.p64, sc_blockSize); Mix(buf, h0,h1,h2,h3,h4,h5,h6,h7,h8,h9,h10,h11); u.p64 += sc_numVars; } } // handle the last partial block of sc_blockSize bytes remainder = (length - ((const uint8 *)end-(const uint8 *)message)); memcpy(buf, end, remainder); memset(((uint8 *)buf)+remainder, 0, sc_blockSize-remainder); ((uint8 *)buf)[sc_blockSize-1] = static_cast(remainder); // do some final mixing End(buf, h0,h1,h2,h3,h4,h5,h6,h7,h8,h9,h10,h11); *hash1 = h0; *hash2 = h1; } #ifdef OPENSUBDIV3_BFR_HASH_INCLUDE_UNUSED_FUNCTIONS // init spooky state void SpookyHash::Init(uint64 seed1, uint64 seed2) { m_length = 0; m_remainder = 0; m_state[0] = seed1; m_state[1] = seed2; } // add a message fragment to the state void SpookyHash::Update(const void *message, size_t length) { uint64 h0,h1,h2,h3,h4,h5,h6,h7,h8,h9,h10,h11; size_t newLength = length + m_remainder; uint8 remainder; union { const uint8 *p8; uint64 *p64; size_t i; } u; const uint64 *end; // Is this message fragment too short? If it is, stuff it away. if (newLength < sc_bufSize) { memcpy(&((uint8 *)m_data)[m_remainder], message, length); m_length = length + m_length; m_remainder = (uint8)newLength; return; } // init the variables if (m_length < sc_bufSize) { h0=h3=h6=h9 = m_state[0]; h1=h4=h7=h10 = m_state[1]; h2=h5=h8=h11 = sc_const; } else { h0 = m_state[0]; h1 = m_state[1]; h2 = m_state[2]; h3 = m_state[3]; h4 = m_state[4]; h5 = m_state[5]; h6 = m_state[6]; h7 = m_state[7]; h8 = m_state[8]; h9 = m_state[9]; h10 = m_state[10]; h11 = m_state[11]; } m_length = length + m_length; // if we've got anything stuffed away, use it now if (m_remainder) { uint8 prefix = sc_bufSize-m_remainder; memcpy(&(((uint8 *)m_data)[m_remainder]), message, prefix); u.p64 = m_data; Mix(u.p64, h0,h1,h2,h3,h4,h5,h6,h7,h8,h9,h10,h11); Mix(&u.p64[sc_numVars], h0,h1,h2,h3,h4,h5,h6,h7,h8,h9,h10,h11); u.p8 = ((const uint8 *)message) + prefix; length -= prefix; } else { u.p8 = (const uint8 *)message; } // handle all whole blocks of sc_blockSize bytes end = u.p64 + (length/sc_blockSize)*sc_numVars; remainder = (uint8)(length-((const uint8 *)end-u.p8)); if (ALLOW_UNALIGNED_READS || (u.i & 0x7) == 0) { while (u.p64 < end) { Mix(u.p64, h0,h1,h2,h3,h4,h5,h6,h7,h8,h9,h10,h11); u.p64 += sc_numVars; } } else { while (u.p64 < end) { memcpy(m_data, u.p8, sc_blockSize); Mix(m_data, h0,h1,h2,h3,h4,h5,h6,h7,h8,h9,h10,h11); u.p64 += sc_numVars; } } // stuff away the last few bytes m_remainder = remainder; memcpy(m_data, end, remainder); // stuff away the variables m_state[0] = h0; m_state[1] = h1; m_state[2] = h2; m_state[3] = h3; m_state[4] = h4; m_state[5] = h5; m_state[6] = h6; m_state[7] = h7; m_state[8] = h8; m_state[9] = h9; m_state[10] = h10; m_state[11] = h11; } // report the hash for the concatenation of all message fragments so far void SpookyHash::Final(uint64 *hash1, uint64 *hash2) { // init the variables if (m_length < sc_bufSize) { *hash1 = m_state[0]; *hash2 = m_state[1]; Short( m_data, m_length, hash1, hash2); return; } const uint64 *data = (const uint64 *)m_data; uint8 remainder = m_remainder; uint64 h0 = m_state[0]; uint64 h1 = m_state[1]; uint64 h2 = m_state[2]; uint64 h3 = m_state[3]; uint64 h4 = m_state[4]; uint64 h5 = m_state[5]; uint64 h6 = m_state[6]; uint64 h7 = m_state[7]; uint64 h8 = m_state[8]; uint64 h9 = m_state[9]; uint64 h10 = m_state[10]; uint64 h11 = m_state[11]; if (remainder >= sc_blockSize) { // m_data can contain two blocks; handle any whole first block Mix(data, h0,h1,h2,h3,h4,h5,h6,h7,h8,h9,h10,h11); data += sc_numVars; remainder -= sc_blockSize; } // mix in the last partial block, and the length mod sc_blockSize memset(&((uint8 *)data)[remainder], 0, (sc_blockSize-remainder)); ((uint8 *)data)[sc_blockSize-1] = remainder; // do some final mixing End(data, h0,h1,h2,h3,h4,h5,h6,h7,h8,h9,h10,h11); *hash1 = h0; *hash2 = h1; } #endif } // anon // // Public functions exposed for OpenSubdiv: // namespace OpenSubdiv { namespace OPENSUBDIV_VERSION { namespace Bfr { namespace internal { uint32_t Hash32(const void *data, size_t len) { return SpookyHash::Hash32(data, len, /*seed=*/0); } uint32_t Hash32(const void *data, size_t len, uint32_t seed) { return SpookyHash::Hash32(data, len, seed); } uint64_t Hash64(const void *data, size_t len) { return SpookyHash::Hash64(data, len, /*seed=*/0); } uint64_t Hash64(const void *data, size_t len, uint64_t seed) { return SpookyHash::Hash64(data, len, seed); } } // end namespace internal } // end namespace Bfr } // end namespace OPENSUBDIV_VERSION } // end namespace OpenSubdiv