--- /dev/null
+/*
+ * Copyright 2017 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/hash/SpookyHashV2.h>
+
+#include <folly/CppAttributes.h>
+#include <folly/Portability.h>
+
+#include <cstring>
+
+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 (!kHasUnalignedAccess && (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;
+ FOLLY_FALLTHROUGH;
+ case 14:
+ d += ((uint64_t)u.p8[13]) << 40;
+ FOLLY_FALLTHROUGH;
+ case 13:
+ d += ((uint64_t)u.p8[12]) << 32;
+ FOLLY_FALLTHROUGH;
+ case 12:
+ d += u.p32[2];
+ c += u.p64[0];
+ break;
+ case 11:
+ d += ((uint64_t)u.p8[10]) << 16;
+ FOLLY_FALLTHROUGH;
+ case 10:
+ d += ((uint64_t)u.p8[9]) << 8;
+ FOLLY_FALLTHROUGH;
+ case 9:
+ d += (uint64_t)u.p8[8];
+ FOLLY_FALLTHROUGH;
+ case 8:
+ c += u.p64[0];
+ break;
+ case 7:
+ c += ((uint64_t)u.p8[6]) << 48;
+ FOLLY_FALLTHROUGH;
+ case 6:
+ c += ((uint64_t)u.p8[5]) << 40;
+ FOLLY_FALLTHROUGH;
+ case 5:
+ c += ((uint64_t)u.p8[4]) << 32;
+ FOLLY_FALLTHROUGH;
+ case 4:
+ c += u.p32[0];
+ break;
+ case 3:
+ c += ((uint64_t)u.p8[2]) << 16;
+ FOLLY_FALLTHROUGH;
+ case 2:
+ c += ((uint64_t)u.p8[1]) << 8;
+ FOLLY_FALLTHROUGH;
+ 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 (kHasUnalignedAccess || ((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] = uint8_t(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 (kHasUnalignedAccess || (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) const
+{
+ // 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_t buf[2*sc_numVars];
+ memcpy(buf, m_data, sizeof(buf));
+ uint64_t *data = buf;
+ 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
projects / folly.git / blobdiff