Module: Shipeasy::SDK::Murmur3

Defined in:
lib/shipeasy/sdk/murmur3.rb

Constant Summary collapse

C1 = 
0xcc9e2d51
C2 = 
0x1b873593
MASK32 = 
0xFFFFFFFF

Class Method Summary collapse

Class Method Details

.fmix32(h) ⇒ Object 



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# File 'lib/shipeasy/sdk/murmur3.rb', line 44

def self.fmix32(h)
  h ^= (h >> 16)
  h  = (h * 0x85ebca6b) & MASK32
  h ^= (h >> 13)
  h  = (h * 0xc2b2ae35) & MASK32
  h ^= (h >> 16)
  h
end

.hash32(key, seed = 0) ⇒ Object 



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# File 'lib/shipeasy/sdk/murmur3.rb', line 8

def self.hash32(key, seed = 0)
  bytes = key.encode("UTF-8").bytes
  len   = bytes.length
  h1    = seed

  (len / 4).times do |i|
    off = i * 4
    k1 = bytes[off] | (bytes[off + 1] << 8) | (bytes[off + 2] << 16) | (bytes[off + 3] << 24)
    k1 = (k1 & MASK32)
    k1 = ((k1 * C1) & MASK32)
    k1 = ((k1 << 15) | (k1 >> 17)) & MASK32
    k1 = ((k1 * C2) & MASK32)
    h1 ^= k1
    h1 = ((h1 << 13) | (h1 >> 19)) & MASK32
    h1 = ((h1 * 5) & MASK32)
    h1 = (h1 + 0xe6546b64) & MASK32
  end

  tail   = (len / 4) * 4
  k1     = 0
  remain = len & 3
  k1 ^= (bytes[tail + 2] << 16) if remain >= 3
  k1 ^= (bytes[tail + 1] << 8)  if remain >= 2
  k1 ^= bytes[tail]              if remain >= 1
  if remain > 0
    k1 = (k1 * C1) & MASK32
    k1 = ((k1 << 15) | (k1 >> 17)) & MASK32
    k1 = (k1 * C2) & MASK32
    h1 ^= k1
  end

  h1 ^= len
  h1  = fmix32(h1)
  h1
end