faux-folly/folly/SpookyHashV2.cpp - nest-cam/4320010/faux-folly - Git at Google

 /*
  * Copyright 2015 Facebook, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *   http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 // 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 <folly/SpookyHashV2.h>

 #include <cstring>

 #define ALLOW_UNALIGNED_READS 1

 namespace folly {
 namespace hash {

 //
 // short hash ... it could be used on any message,
 // but it's used by Spooky just for short messages.
 //
 void SpookyHashV2::Short(
     const void *message,
     size_t length,
     uint64_t *hash1,
     uint64_t *hash2)
 {
     uint64_t buf[2*sc_numVars];
     union
     {
         const uint8_t *p8;
         uint32_t *p32;
         uint64_t *p64;
         size_t i;
     } u;

     u.p8 = (const uint8_t *)message;

     if (!ALLOW_UNALIGNED_READS && (u.i & 0x7))
     {
         memcpy(buf, message, length);
         u.p64 = buf;
     }

     size_t remainder = length%32;
     uint64_t a=*hash1;
     uint64_t b=*hash2;
     uint64_t c=sc_const;
     uint64_t d=sc_const;

     if (length > 15)
     {
         const uint64_t *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_t)length) << 56;
     switch (remainder)
     {
     case 15:
     d += ((uint64_t)u.p8[14]) << 48;
     case 14:
         d += ((uint64_t)u.p8[13]) << 40;
     case 13:
         d += ((uint64_t)u.p8[12]) << 32;
     case 12:
         d += u.p32[2];
         c += u.p64[0];
         break;
     case 11:
         d += ((uint64_t)u.p8[10]) << 16;
     case 10:
         d += ((uint64_t)u.p8[9]) << 8;
     case 9:
         d += (uint64_t)u.p8[8];
     case 8:
         c += u.p64[0];
         break;
     case 7:
         c += ((uint64_t)u.p8[6]) << 48;
     case 6:
         c += ((uint64_t)u.p8[5]) << 40;
     case 5:
         c += ((uint64_t)u.p8[4]) << 32;
     case 4:
         c += u.p32[0];
         break;
     case 3:
         c += ((uint64_t)u.p8[2]) << 16;
     case 2:
         c += ((uint64_t)u.p8[1]) << 8;
     case 1:
         c += (uint64_t)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 SpookyHashV2::Hash128(
     const void *message,
     size_t length,
     uint64_t *hash1,
     uint64_t *hash2)
 {
     if (length < sc_bufSize)
     {
         Short(message, length, hash1, hash2);
         return;
     }

     uint64_t h0,h1,h2,h3,h4,h5,h6,h7,h8,h9,h10,h11;
     uint64_t buf[sc_numVars];
     uint64_t *end;
     union
     {
         const uint8_t *p8;
         uint64_t *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_t *)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_t *)end-(const uint8_t *)message));
     memcpy(buf, end, remainder);
     memset(((uint8_t *)buf)+remainder, 0, sc_blockSize-remainder);
     ((uint8_t *)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 SpookyHashV2::Init(uint64_t seed1, uint64_t seed2)
 {
     m_length = 0;
     m_remainder = 0;
     m_state[0] = seed1;
     m_state[1] = seed2;
 }


 // add a message fragment to the state
 void SpookyHashV2::Update(const void *message, size_t length)
 {
     uint64_t h0,h1,h2,h3,h4,h5,h6,h7,h8,h9,h10,h11;
     size_t newLength = length + m_remainder;
     uint8_t  remainder;
     union
     {
         const uint8_t *p8;
         uint64_t *p64;
         size_t i;
     } u;
     const uint64_t *end;

     // Is this message fragment too short?  If it is, stuff it away.
     if (newLength < sc_bufSize)
     {
         memcpy(&((uint8_t *)m_data)[m_remainder], message, length);
         m_length = length + m_length;
         m_remainder = (uint8_t)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_t prefix = sc_bufSize-m_remainder;
         memcpy(&(((uint8_t *)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_t *)message) + prefix;
         length -= prefix;
     }
     else
     {
         u.p8 = (const uint8_t *)message;
     }

     // handle all whole blocks of sc_blockSize bytes
     end = u.p64 + (length/sc_blockSize)*sc_numVars;
     remainder = (uint8_t)(length-((const uint8_t *)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 SpookyHashV2::Final(uint64_t *hash1, uint64_t *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_t *data = (const uint64_t *)m_data;
     uint8_t remainder = m_remainder;

     uint64_t h0 = m_state[0];
     uint64_t h1 = m_state[1];
     uint64_t h2 = m_state[2];
     uint64_t h3 = m_state[3];
     uint64_t h4 = m_state[4];
     uint64_t h5 = m_state[5];
     uint64_t h6 = m_state[6];
     uint64_t h7 = m_state[7];
     uint64_t h8 = m_state[8];
     uint64_t h9 = m_state[9];
     uint64_t h10 = m_state[10];
     uint64_t 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_t *)data)[remainder], 0, (sc_blockSize-remainder));

     ((uint8_t *)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;
 }

 }  // namespace hash
 }  // namespace folly
	/*
	* Copyright 2015 Facebook, Inc.
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	// 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 <folly/SpookyHashV2.h>

	#include <cstring>

	#define ALLOW_UNALIGNED_READS 1

	namespace folly {
	namespace hash {

	//
	// short hash ... it could be used on any message,
	// but it's used by Spooky just for short messages.
	//
	void SpookyHashV2::Short(
	const void *message,
	size_t length,
	uint64_t *hash1,
	uint64_t *hash2)
	{
	uint64_t buf[2*sc_numVars];
	union
	{
	const uint8_t *p8;
	uint32_t *p32;
	uint64_t *p64;
	size_t i;
	} u;

	u.p8 = (const uint8_t *)message;

	if (!ALLOW_UNALIGNED_READS && (u.i & 0x7))
	{
	memcpy(buf, message, length);
	u.p64 = buf;
	}

	size_t remainder = length%32;
	uint64_t a=*hash1;
	uint64_t b=*hash2;
	uint64_t c=sc_const;
	uint64_t d=sc_const;

	if (length > 15)
	{
	const uint64_t 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_t)length) << 56;
	switch (remainder)
	{
	case 15:
	d += ((uint64_t)u.p8[14]) << 48;
	case 14:
	d += ((uint64_t)u.p8[13]) << 40;
	case 13:
	d += ((uint64_t)u.p8[12]) << 32;
	case 12:
	d += u.p32[2];
	c += u.p64[0];
	break;
	case 11:
	d += ((uint64_t)u.p8[10]) << 16;
	case 10:
	d += ((uint64_t)u.p8[9]) << 8;
	case 9:
	d += (uint64_t)u.p8[8];
	case 8:
	c += u.p64[0];
	break;
	case 7:
	c += ((uint64_t)u.p8[6]) << 48;
	case 6:
	c += ((uint64_t)u.p8[5]) << 40;
	case 5:
	c += ((uint64_t)u.p8[4]) << 32;
	case 4:
	c += u.p32[0];
	break;
	case 3:
	c += ((uint64_t)u.p8[2]) << 16;
	case 2:
	c += ((uint64_t)u.p8[1]) << 8;
	case 1:
	c += (uint64_t)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 SpookyHashV2::Hash128(
	const void *message,
	size_t length,
	uint64_t *hash1,
	uint64_t *hash2)
	{
	if (length < sc_bufSize)
	{
	Short(message, length, hash1, hash2);
	return;
	}

	uint64_t h0,h1,h2,h3,h4,h5,h6,h7,h8,h9,h10,h11;
	uint64_t buf[sc_numVars];
	uint64_t *end;
	union
	{
	const uint8_t *p8;
	uint64_t *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_t *)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_t )end-(const uint8_t )message));
	memcpy(buf, end, remainder);
	memset(((uint8_t *)buf)+remainder, 0, sc_blockSize-remainder);
	((uint8_t *)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 SpookyHashV2::Init(uint64_t seed1, uint64_t seed2)
	{
	m_length = 0;
	m_remainder = 0;
	m_state[0] = seed1;
	m_state[1] = seed2;
	}


	// add a message fragment to the state
	void SpookyHashV2::Update(const void *message, size_t length)
	{
	uint64_t h0,h1,h2,h3,h4,h5,h6,h7,h8,h9,h10,h11;
	size_t newLength = length + m_remainder;
	uint8_t remainder;
	union
	{
	const uint8_t *p8;
	uint64_t *p64;
	size_t i;
	} u;
	const uint64_t *end;

	// Is this message fragment too short? If it is, stuff it away.
	if (newLength < sc_bufSize)
	{
	memcpy(&((uint8_t *)m_data)[m_remainder], message, length);
	m_length = length + m_length;
	m_remainder = (uint8_t)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_t prefix = sc_bufSize-m_remainder;
	memcpy(&(((uint8_t *)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_t *)message) + prefix;
	length -= prefix;
	}
	else
	{
	u.p8 = (const uint8_t *)message;
	}

	// handle all whole blocks of sc_blockSize bytes
	end = u.p64 + (length/sc_blockSize)*sc_numVars;
	remainder = (uint8_t)(length-((const uint8_t *)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 SpookyHashV2::Final(uint64_t hash1, uint64_t 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_t data = (const uint64_t )m_data;
	uint8_t remainder = m_remainder;

	uint64_t h0 = m_state[0];
	uint64_t h1 = m_state[1];
	uint64_t h2 = m_state[2];
	uint64_t h3 = m_state[3];
	uint64_t h4 = m_state[4];
	uint64_t h5 = m_state[5];
	uint64_t h6 = m_state[6];
	uint64_t h7 = m_state[7];
	uint64_t h8 = m_state[8];
	uint64_t h9 = m_state[9];
	uint64_t h10 = m_state[10];
	uint64_t 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_t *)data)[remainder], 0, (sc_blockSize-remainder));

	((uint8_t *)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;
	}

	} // namespace hash
	} // namespace folly