github.com/m3db/stackmurmur3@v1.0.1/murmur.go (about)

     1  // Copyright 2013, Sébastien Paolacci. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  /*
     6  Package murmur3 implements Austin Appleby's non-cryptographic MurmurHash3.
     7  
     8   Reference implementation:
     9      http://code.google.com/p/smhasher/wiki/MurmurHash3
    10  
    11   History, characteristics and (legacy) perfs:
    12      https://sites.google.com/site/murmurhash/
    13      https://sites.google.com/site/murmurhash/statistics
    14  */
    15  package murmur3
    16  
    17  type digest struct {
    18  	clen int      // Digested input cumulative length.
    19  	buf  [16]byte // Expected (but not required) to be Size() large.
    20  	seed uint32   // Seed for initializing the hash.
    21  	tail int      // Length used in buf to store tailing unprocessed bytes.
    22  }
    23  
    24  func (d digest) BlockSize() int {
    25  	return 1
    26  }
    27  
    28  func (d digest) loadUint32(idx int) uint32 {
    29  	b := idx * 4
    30  	return uint32(d.buf[b+0]) | uint32(d.buf[b+1])<<8 | uint32(d.buf[b+2])<<16 | uint32(d.buf[b+3])<<24
    31  }
    32  
    33  func (d digest) loadUint64(idx int) uint64 {
    34  	b := idx * 8
    35  	return uint64(d.buf[b+0]) | uint64(d.buf[b+1])<<8 | uint64(d.buf[b+2])<<16 | uint64(d.buf[b+3])<<24 |
    36  		uint64(d.buf[b+4])<<32 | uint64(d.buf[b+5])<<40 | uint64(d.buf[b+6])<<48 | uint64(d.buf[b+7])<<56
    37  }