Class: XXhash::XXhashInternal::XXhash64

Inherits:
Object
  • Object
show all
Defined in:
lib/ruby-xxhash64.rb

Constant Summary collapse

@@mem_total_size = 
32
@@prime64_1 = 
11400714785074694791
@@prime64_2 = 
14029467366897019727
@@prime64_3 = 
1609587929392839161
@@prime64_4 = 
9650029242287828579
@@prime64_5 = 
2870177450012600261
@@sixtyfour1s = 
(2**64-1)

Instance Method Summary collapse

Constructor Details

#initialize(seed) ⇒ XXhash64

Returns a new instance of XXhash64.



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# File 'lib/ruby-xxhash64.rb', line 15

def initialize seed
  @seed = seed
  reset
end

Instance Method Details

#digest(val = nil) ⇒ Object 



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# File 'lib/ruby-xxhash64.rb', line 72

def digest val=nil
  if val
    update val
  end

  if @total_len >= 32
    h64 = ((@v1 << 1) | (@v1 >> (64 - 1))) +
      ((@v2 << 7) | (@v2 >> (64 - 7))) +
      ((@v3 << 12) | (@v3 >> (64 - 12))) +
      ((@v4 << 18) | (@v4 >> (64 - 18)))

    [:v1, :v2, :v3, :v4].each do |m|
      v = uint64(self.send(m) * @@prime64_2)
      v = uint64((v << 31) | (v >> (64 - 31)))
      h64 ^= uint64(v * @@prime64_1)
      h64 = h64 * @@prime64_1 + @@prime64_4
    end
  else
    h64 = @seed + @@prime64_5
  end

  h64 = uint64(h64 + @total_len)

  i = 0
  while i <= (@memsize - 8)
    v = uint64(
      @memory[i] |
        (@memory[i+1] << 8) |
        (@memory[i+2] << 16) |
        (@memory[i+3] << 24) |
        (@memory[i+4] << 32) |
        (@memory[i+5] << 40) |
        (@memory[i+6] << 48) |
        (@memory[i+7] << 56))

    v = uint64(v * @@prime64_2)
    h64 ^= uint64(uint64((v << 31) | (v >> (64 - 31))) * @@prime64_1)
    h64 = uint64(uint64((h64 << 27) | (h64 >> (64 - 27))) * @@prime64_1 + @@prime64_4)
    i += 8
  end

  if i <= (@memsize - 4)
    v = @memory[i] |
      (@memory[i+1] << 8) |
      (@memory[i+2] << 16) |
      (@memory[i+3] << 24)
    h64 ^= uint64(v * @@prime64_1)
    h64 = uint64(uint64((h64 << 23) | (h64 >> (64-23))) * @@prime64_2 + @@prime64_3)
    i += 4
  end

  while i < @memsize
    h64 ^= uint64(@memory[i] * @@prime64_5)
    h64 = uint64(uint64((h64 << 11) | (h64 >> (64 - 11))) * @@prime64_1)
    i += 1
  end

  h64 ^= h64 >> 33
  h64 = uint64(h64 * @@prime64_2)
  h64 ^= h64 >> 29
  h64 = uint64(h64 * @@prime64_3)
  h64 ^= h64 >> 32

  h64
end

#reset ⇒ Object 



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# File 'lib/ruby-xxhash64.rb', line 20

def reset
  @v1 = @seed + @@prime64_1 + @@prime64_2;
  @v2 = @seed + @@prime64_2;
  @v3 = @seed + 0;
  @v4 = @seed - @@prime64_1;
  @total_len = 0
  @memory = Array.new(@@mem_total_size)
  @memsize = 0
end

#update(bytes) ⇒ Object 



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# File 'lib/ruby-xxhash64.rb', line 30

def update bytes
  if String === bytes
    bytes = bytes.unpack("C*")
  end

  @total_len += bytes.length

  p = 0
  while (remaining = (bytes.length - p)) > 0
    mem_avail = @@mem_total_size - @memsize

    if(remaining < mem_avail)
      @memory[@memsize, remaining] = bytes[p, remaining]
      @memsize += remaining
      break
    end

    @memory[@memsize, mem_avail] = bytes[p, mem_avail]

    i = 0
    [:v1, :v2, :v3, :v4].each do |m|
      p64 = uint64(
        @memory[i] |
          (@memory[i+1] << 8) |
          (@memory[i+2] << 16) |
          (@memory[i+3] << 24) |
          (@memory[i+4] << 32) |
          (@memory[i+5] << 40) |
          (@memory[i+6] << 48) |
          (@memory[i+7] << 56))

      v = uint64(self.send(m) + p64 * @@prime64_2)
      v = uint64(uint64((v << 31) | (v >> (64 - 31))) * @@prime64_1)
      self.send((m.to_s + "=").to_sym, v)
      i += 8
    end

    p += mem_avail
    @memsize = 0
  end
end