module Bundler::Digest - bundler: Ruby Standard Library Documentation

# module Bundler::Digest

### Constants

SHA1_MASK

  The 8-bit field used for bitwise ‘AND` masking. Defaults to `0xFFFFFFFF`.

SHA1_WORDS

  The initial constant values for the 32-bit constant words A, B, C, D, and E, respectively.

### Public Class Methods

sha1(string) click to toggle source

    # File bundler/digest.rb, line 14
    def sha1(string)
      unless string.is_a?(String)
        raise TypeError, "can't convert #{string.class.inspect} into String"
      end

      buffer = string.b

      words = SHA1_WORDS.dup
      generate_split_buffer(buffer) do |chunk|
        w = []
        chunk.each_slice(4) do |a, b, c, d|
          w << (((a << 8 | b) << 8 | c) << 8 | d)
        end
        a, b, c, d, e = *words
        (16..79).each do |i|
          w[i] = SHA1_MASK & rotate((w[i - 3] ^ w[i - 8] ^ w[i - 14] ^ w[i - 16]), 1)
        end
        0.upto(79) do |i|
          case i
          when  0..19
            f = ((b & c) | (~b & d))
            k = 0x5A827999
          when 20..39
            f = (b ^ c ^ d)
            k = 0x6ED9EBA1
          when 40..59
            f = ((b & c) | (b & d) | (c & d))
            k = 0x8F1BBCDC
          when 60..79
            f = (b ^ c ^ d)
            k = 0xCA62C1D6
          end
          t = SHA1_MASK & rotate(a, 5) + f + e + k + w[i]
          a, b, c, d, e = t, a, SHA1_MASK & rotate(b, 30), c, d # rubocop:disable Style/ParallelAssignment
        end
        mutated = [a, b, c, d, e]
        words.map!.with_index {|word, index| SHA1_MASK & (word + mutated[index]) }
      end

      words.pack("N*").unpack1("H*")
    end

### Private Class Methods

generate_split_buffer(string, &block) click to toggle source

    # File bundler/digest.rb, line 58
    def generate_split_buffer(string, &block)
      size   = string.bytesize * 8
      buffer = string.bytes << 128
      buffer << 0 while buffer.size % 64 != 56
      buffer.concat([size].pack("Q>").bytes)
      buffer.each_slice(64, &block)
    end

rotate(value, spaces) click to toggle source

    # File bundler/digest.rb, line 66
    def rotate(value, spaces)
      value << spaces | value >> (32 - spaces)
    end