spooky.cc

/*
 * Copyright (c) 2008-2014, Pedigree Developers
 *
 * Please see the CONTRIB file in the root of the source tree for a full
 * list of contributors.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */
 
// Spooky Hash
// A 128-bit noncryptographic hash, for checksums and table lookup
// By Bob Jenkins.  Public domain.
//   Oct 31 2010: published framework, disclaimer ShortHash isn't right
//   Nov 7 2010: disabled ShortHash
//   Oct 31 2011: replace End, ShortMix, ShortEnd, enable ShortHash again
//   April 10 2012: buffer overflow on platforms without unaligned reads
//   July 12 2012: was passing out variables in final to in/out in short
//   July 30 2012: I reintroduced the buffer overflow
//   August 5 2012: SpookyV2: d = should be d += in short hash, and remove extra mix from long hash
 
#include "pedigree/kernel/utilities/spooky/SpookyV2.h"
#include "pedigree/kernel/utilities/utility.h"
 
#define memcpy MemoryCopy
#define memset ByteSet
 
#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;
      [[fallthrough]];
    case 14:
      d += ((uint64)u.p8[13]) << 40;
      [[fallthrough]];
    case 13:
      d += ((uint64)u.p8[12]) << 32;
      [[fallthrough]];
    case 12:
      d += u.p32[2];
      c += u.p64[0];
      break;
    case 11:
      d += ((uint64)u.p8[10]) << 16;
      [[fallthrough]];
    case 10:
      d += ((uint64)u.p8[9]) << 8;
      [[fallthrough]];
    case 9:
      d += (uint64)u.p8[8];
      [[fallthrough]];
    case 8:
      c += u.p64[0];
      break;
    case 7:
      c += ((uint64)u.p8[6]) << 48;
      [[fallthrough]];
    case 6:
      c += ((uint64)u.p8[5]) << 40;
      [[fallthrough]];
    case 5:
      c += ((uint64)u.p8[4]) << 32;
      [[fallthrough]];
    case 4:
      c += u.p32[0];
      break;
    case 3:
      c += ((uint64)u.p8[2]) << 16;
      [[fallthrough]];
    case 2:
      c += ((uint64)u.p8[1]) << 8;
      [[fallthrough]];
    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] = remainder;
 
  // do some final mixing
  End(buf, h0, h1, h2, h3, h4, h5, h6, h7, h8, h9, h10, h11);
  *hash1 = h0;
  *hash2 = h1;
}
 
// 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;
  }
 
  uint64* data = (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;
}