ruby--ruby/test/-ext-/bignum/test_pack.rb

# coding: ASCII-8BIT
# frozen_string_literal: false

require 'test/unit'
require "-test-/bignum"

class TestBignum < Test::Unit::TestCase
  class TestPack < Test::Unit::TestCase

    MSWORD_FIRST = Integer::INTEGER_PACK_MSWORD_FIRST
    LSWORD_FIRST = Integer::INTEGER_PACK_LSWORD_FIRST
    MSBYTE_FIRST = Integer::INTEGER_PACK_MSBYTE_FIRST
    LSBYTE_FIRST = Integer::INTEGER_PACK_LSBYTE_FIRST
    NATIVE_BYTE_ORDER = Integer::INTEGER_PACK_NATIVE_BYTE_ORDER
    TWOCOMP = Integer::INTEGER_PACK_2COMP
    LITTLE_ENDIAN = Integer::INTEGER_PACK_LITTLE_ENDIAN
    BIG_ENDIAN = Integer::INTEGER_PACK_BIG_ENDIAN
    NEGATIVE = Integer::INTEGER_PACK_NEGATIVE
    GENERIC = Integer::INTEGER_PACK_FORCE_GENERIC_IMPLEMENTATION

    def test_pack_zero
      assert_equal([0, ""], 0.test_pack(0, 1, 0, BIG_ENDIAN))
    end

    def test_pack_argument_check
      assert_raise(ArgumentError) { 0.test_pack_raw("", 2, 1, 0, MSBYTE_FIRST) }
      assert_raise(ArgumentError) { 0.test_pack_raw("", 0, 1, 0, MSWORD_FIRST) }
      assert_raise(ArgumentError) { 0.test_pack_raw("", 0, 0, 0, BIG_ENDIAN) }
      assert_raise(ArgumentError) { 0.test_pack_raw("", 0, 1, 8, BIG_ENDIAN) }

      # assume sizeof(ssize_t) == sizeof(intptr_t)
      assert_raise(ArgumentError) { 0.test_pack_raw("", 1 << ([""].pack("p").length * 8 - 1), 0, BIG_ENDIAN) }
    end

    def test_pack_wordsize
      assert_equal([1, "\x01"], 1.test_pack(1, 1, 0, BIG_ENDIAN))
      assert_equal([1, "\x00\x01"], 1.test_pack(1, 2, 0, BIG_ENDIAN))
      assert_equal([1, "\x00\x00\x01"], 1.test_pack(1, 3, 0, BIG_ENDIAN))
      assert_equal([1, "\x01"], 1.test_pack(1, 1, 0, LITTLE_ENDIAN))
      assert_equal([1, "\x01\x00"], 1.test_pack(1, 2, 0, LITTLE_ENDIAN))
      assert_equal([1, "\x01\x00\x00"], 1.test_pack(1, 3, 0, LITTLE_ENDIAN))
    end

    def test_pack_fixed_buffer
      assert_equal([0, "\x00\x00"], 0.test_pack(2, 1, 0, BIG_ENDIAN))
      assert_equal([1, "\x00\x01"], 0x01.test_pack(2, 1, 0, BIG_ENDIAN))
      assert_equal([1, "\x02\x01"], 0x0201.test_pack(2, 1, 0, BIG_ENDIAN))
      assert_equal([2, "\x02\x01"], 0x030201.test_pack(2, 1, 0, BIG_ENDIAN))
      assert_equal([2, "\x02\x01"], 0x04030201.test_pack(2, 1, 0, BIG_ENDIAN))
      assert_equal([0, "\x00\x00"], 0.test_pack(2, 1, 0, LITTLE_ENDIAN))
      assert_equal([1, "\x01\x00"], 0x01.test_pack(2, 1, 0, LITTLE_ENDIAN))
      assert_equal([1, "\x01\x02"], 0x0201.test_pack(2, 1, 0, LITTLE_ENDIAN))
      assert_equal([2, "\x01\x02"], 0x030201.test_pack(2, 1, 0, LITTLE_ENDIAN))
      assert_equal([2, "\x01\x02"], 0x04030201.test_pack(2, 1, 0, LITTLE_ENDIAN))
    end

    def test_pack_wordorder_and_endian
      assert_equal([1, "\x12\x34\x56\x78"], 0x12345678.test_pack(2, 2, 0, MSWORD_FIRST|MSBYTE_FIRST))
      assert_equal([1, "\x34\x12\x78\x56"], 0x12345678.test_pack(2, 2, 0, MSWORD_FIRST|LSBYTE_FIRST))
      assert_equal([1, "\x56\x78\x12\x34"], 0x12345678.test_pack(2, 2, 0, LSWORD_FIRST|MSBYTE_FIRST))
      assert_equal([1, "\x78\x56\x34\x12"], 0x12345678.test_pack(2, 2, 0, LSWORD_FIRST|LSBYTE_FIRST))
    end

    def test_pack_native_endian
      assert_equal([1, [0x1234].pack("S!")], 0x1234.test_pack(1, 2, 0, MSWORD_FIRST|NATIVE_BYTE_ORDER))
    end

    def test_pack_nail
      assert_equal([1, "\x01\x00\x00\x00\x01\x01"], 0b100011.test_pack(6, 1, 7, BIG_ENDIAN))
      assert_equal([1, "\x01\x02\x03\x04\x05\x06\x07\x08"], 0x12345678.test_pack(8, 1, 4, BIG_ENDIAN))
      assert_equal([1, "\x00\x12\x00\x34\x00\x56\x00\x78"], 0x12345678.test_pack(4, 2, 8, BIG_ENDIAN))
    end

    def test_pack_overflow
      assert_equal([-2, "\x1"], (-0x11).test_pack(1, 1, 4, BIG_ENDIAN))
      assert_equal([-2, "\x0"], (-0x10).test_pack(1, 1, 4, BIG_ENDIAN))
      assert_equal([-1, "\xF"], (-0x0F).test_pack(1, 1, 4, BIG_ENDIAN))
      assert_equal([+1, "\xF"], (+0x0F).test_pack(1, 1, 4, BIG_ENDIAN))
      assert_equal([+2, "\x0"], (+0x10).test_pack(1, 1, 4, BIG_ENDIAN))
      assert_equal([+2, "\x1"], (+0x11).test_pack(1, 1, 4, BIG_ENDIAN))

      assert_equal([-2, "\x01"], (-0x101).test_pack(1, 1, 0, BIG_ENDIAN))
      assert_equal([-2, "\x00"], (-0x100).test_pack(1, 1, 0, BIG_ENDIAN))
      assert_equal([-1, "\xFF"], (-0x0FF).test_pack(1, 1, 0, BIG_ENDIAN))
      assert_equal([+1, "\xFF"], (+0x0FF).test_pack(1, 1, 0, BIG_ENDIAN))
      assert_equal([+2, "\x00"], (+0x100).test_pack(1, 1, 0, BIG_ENDIAN))
      assert_equal([+2, "\x01"], (+0x101).test_pack(1, 1, 0, BIG_ENDIAN))

      assert_equal([-2, "\x00\x00\x00\x00\x00\x00\x00\x01"], (-0x10000000000000001).test_pack(2, 4, 0, BIG_ENDIAN))
      assert_equal([-2, "\x00\x00\x00\x00\x00\x00\x00\x00"], (-0x10000000000000000).test_pack(2, 4, 0, BIG_ENDIAN))
      assert_equal([-1, "\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF"], (-0x0FFFFFFFFFFFFFFFF).test_pack(2, 4, 0, BIG_ENDIAN))
      assert_equal([+1, "\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF"], (+0x0FFFFFFFFFFFFFFFF).test_pack(2, 4, 0, BIG_ENDIAN))
      assert_equal([+2, "\x00\x00\x00\x00\x00\x00\x00\x00"], (+0x10000000000000000).test_pack(2, 4, 0, BIG_ENDIAN))
      assert_equal([+2, "\x00\x00\x00\x00\x00\x00\x00\x01"], (+0x10000000000000001).test_pack(2, 4, 0, BIG_ENDIAN))

      1.upto(16) {|wordsize|
        1.upto(20) {|numwords|
          w = numwords*wordsize
          n = 256**w
          assert_equal([-2, "\x00"*(w-1)+"\x01"], (-n-1).test_pack(numwords, wordsize, 0, BIG_ENDIAN))
          assert_equal([-2, "\x00"*w],            (-n  ).test_pack(numwords, wordsize, 0, BIG_ENDIAN))
          assert_equal([-1, "\xFF"*w],            (-n+1).test_pack(numwords, wordsize, 0, BIG_ENDIAN))
          assert_equal([+1, "\xFF"*w],            (+n-1).test_pack(numwords, wordsize, 0, BIG_ENDIAN))
          assert_equal([+2, "\x00"*w],            (+n  ).test_pack(numwords, wordsize, 0, BIG_ENDIAN))
          assert_equal([+2, "\x00"*(w-1)+"\x01"], (+n+1).test_pack(numwords, wordsize, 0, BIG_ENDIAN))
        }
      }

      1.upto(16) {|wordsize|
        1.upto(20) {|numwords|
          w = numwords*wordsize
          n = 256**w
          assert_equal([-2, "\x01"+"\x00"*(w-1)], (-n-1).test_pack(numwords, wordsize, 0, LITTLE_ENDIAN))
          assert_equal([-2, "\x00"*w],            (-n  ).test_pack(numwords, wordsize, 0, LITTLE_ENDIAN))
          assert_equal([-1, "\xFF"*w],            (-n+1).test_pack(numwords, wordsize, 0, LITTLE_ENDIAN))
          assert_equal([+1, "\xFF"*w],            (+n-1).test_pack(numwords, wordsize, 0, LITTLE_ENDIAN))
          assert_equal([+2, "\x00"*w],            (+n  ).test_pack(numwords, wordsize, 0, LITTLE_ENDIAN))
          assert_equal([+2, "\x01"+"\x00"*(w-1)], (+n+1).test_pack(numwords, wordsize, 0, LITTLE_ENDIAN))
        }
      }
    end

    def test_pack_sign
      assert_equal([-1, "\x01"], (-1).test_pack(1, 1, 0, BIG_ENDIAN))
      assert_equal([-1, "\x80\x70\x60\x50\x40\x30\x20\x10"], (-0x8070605040302010).test_pack(8, 1, 0, BIG_ENDIAN))
    end

    def test_pack_orders
      [MSWORD_FIRST, LSWORD_FIRST].each {|word_order|
        [MSBYTE_FIRST, LSBYTE_FIRST, NATIVE_BYTE_ORDER].each {|byte_order|
          1.upto(16) {|wordsize|
            1.upto(20) {|numwords|
              w = numwords*wordsize
              n = 0;
              0.upto(w) {|i|
                n |= ((i+1) % 256) << (i*8)
              }
              assert_equal(n.test_pack(numwords, wordsize, 0, word_order|byte_order|GENERIC),
                           n.test_pack(numwords, wordsize, 0, word_order|byte_order),
                          "#{'%#x' % n}.test_pack(#{numwords}, #{wordsize}, 0, #{'%#x' % (word_order|byte_order)})")
            }
          }
        }
      }
    end

    def test_pack2comp_zero
      assert_equal([0, ""], 0.test_pack(0, 1, 0, TWOCOMP|BIG_ENDIAN))
    end

    def test_pack2comp_emptybuf
      assert_equal([-2, ""], (-3).test_pack(0, 1, 0, TWOCOMP|BIG_ENDIAN))
      assert_equal([-2, ""], (-2).test_pack(0, 1, 0, TWOCOMP|BIG_ENDIAN))
      assert_equal([-1, ""], (-1).test_pack(0, 1, 0, TWOCOMP|BIG_ENDIAN))
      assert_equal([ 0, ""], 0.test_pack(0, 1, 0, TWOCOMP|BIG_ENDIAN))
      assert_equal([+2, ""], 1.test_pack(0, 1, 0, TWOCOMP|BIG_ENDIAN))
      assert_equal([+2, ""], 2.test_pack(0, 1, 0, TWOCOMP|BIG_ENDIAN))
    end

    def test_pack2comp_nearly_zero
      assert_equal([-1, "\xFE"], (-2).test_pack(1, 1, 0, TWOCOMP|BIG_ENDIAN))
      assert_equal([-1, "\xFF"], (-1).test_pack(1, 1, 0, TWOCOMP|BIG_ENDIAN))
      assert_equal([ 0, "\x00"], 0.test_pack(1, 1, 0, TWOCOMP|BIG_ENDIAN))
      assert_equal([+1, "\x01"], 1.test_pack(1, 1, 0, TWOCOMP|BIG_ENDIAN))
      assert_equal([+1, "\x02"], 2.test_pack(1, 1, 0, TWOCOMP|BIG_ENDIAN))
    end

    def test_pack2comp_overflow
      assert_equal([-2, "\xF"], (-0x11).test_pack(1, 1, 4, TWOCOMP|BIG_ENDIAN))
      assert_equal([-1, "\x0"], (-0x10).test_pack(1, 1, 4, TWOCOMP|BIG_ENDIAN))
      assert_equal([-1, "\x1"], (-0x0F).test_pack(1, 1, 4, TWOCOMP|BIG_ENDIAN))
      assert_equal([+1, "\xF"], (+0x0F).test_pack(1, 1, 4, TWOCOMP|BIG_ENDIAN))
      assert_equal([+2, "\x0"], (+0x10).test_pack(1, 1, 4, TWOCOMP|BIG_ENDIAN))
      assert_equal([+2, "\x1"], (+0x11).test_pack(1, 1, 4, TWOCOMP|BIG_ENDIAN))

      assert_equal([-2, "\xFF"], (-0x101).test_pack(1, 1, 0, TWOCOMP|BIG_ENDIAN))
      assert_equal([-1, "\x00"], (-0x100).test_pack(1, 1, 0, TWOCOMP|BIG_ENDIAN))
      assert_equal([-1, "\x01"], (-0x0FF).test_pack(1, 1, 0, TWOCOMP|BIG_ENDIAN))
      assert_equal([+1, "\xFF"], (+0x0FF).test_pack(1, 1, 0, TWOCOMP|BIG_ENDIAN))
      assert_equal([+2, "\x00"], (+0x100).test_pack(1, 1, 0, TWOCOMP|BIG_ENDIAN))
      assert_equal([+2, "\x01"], (+0x101).test_pack(1, 1, 0, TWOCOMP|BIG_ENDIAN))

      assert_equal([-2, "\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF"], (-0x10000000000000001).test_pack(2, 4, 0, TWOCOMP|BIG_ENDIAN))
      assert_equal([-1, "\x00\x00\x00\x00\x00\x00\x00\x00"], (-0x10000000000000000).test_pack(2, 4, 0, TWOCOMP|BIG_ENDIAN))
      assert_equal([-1, "\x00\x00\x00\x00\x00\x00\x00\x01"], (-0x0FFFFFFFFFFFFFFFF).test_pack(2, 4, 0, TWOCOMP|BIG_ENDIAN))
      assert_equal([+1, "\xFF\xFF\xFF\xFF\xFF\xFF\xFF\xFF"], (+0x0FFFFFFFFFFFFFFFF).test_pack(2, 4, 0, TWOCOMP|BIG_ENDIAN))
      assert_equal([+2, "\x00\x00\x00\x00\x00\x00\x00\x00"], (+0x10000000000000000).test_pack(2, 4, 0, TWOCOMP|BIG_ENDIAN))
      assert_equal([+2, "\x00\x00\x00\x00\x00\x00\x00\x01"], (+0x10000000000000001).test_pack(2, 4, 0, TWOCOMP|BIG_ENDIAN))

      1.upto(16) {|wordsize|
        1.upto(20) {|numwords|
          w = numwords*wordsize
          n = 256**w
          assert_equal([-2, "\xFF"*w           ], (-n-1).test_pack(numwords, wordsize, 0, TWOCOMP|BIG_ENDIAN))
          assert_equal([-1, "\x00"*w],            (-n  ).test_pack(numwords, wordsize, 0, TWOCOMP|BIG_ENDIAN))
          assert_equal([-1, "\x00"*(w-1)+"\x01"], (-n+1).test_pack(numwords, wordsize, 0, TWOCOMP|BIG_ENDIAN))
          assert_equal([+1, "\xFF"*w],            (+n-1).test_pack(numwords, wordsize, 0, TWOCOMP|BIG_ENDIAN))
          assert_equal([+2, "\x00"*w],            (+n  ).test_pack(numwords, wordsize, 0, TWOCOMP|BIG_ENDIAN))
          assert_equal([+2, "\x00"*(w-1)+"\x01"], (+n+1).test_pack(numwords, wordsize, 0, TWOCOMP|BIG_ENDIAN))
        }
      }

      1.upto(16) {|wordsize|
        1.upto(20) {|numwords|
          w = numwords*wordsize
          n = 256**w
          assert_equal([-2, "\xFF"*w           ], (-n-1).test_pack(numwords, wordsize, 0, TWOCOMP|LITTLE_ENDIAN))
          assert_equal([-1, "\x00"*w],            (-n  ).test_pack(numwords, wordsize, 0, TWOCOMP|LITTLE_ENDIAN))
          assert_equal([-1, "\x01"+"\x00"*(w-1)], (-n+1).test_pack(numwords, wordsize, 0, TWOCOMP|LITTLE_ENDIAN))
          assert_equal([+1, "\xFF"*w],            (+n-1).test_pack(numwords, wordsize, 0, TWOCOMP|LITTLE_ENDIAN))
          assert_equal([+2, "\x00"*w],            (+n  ).test_pack(numwords, wordsize, 0, TWOCOMP|LITTLE_ENDIAN))
          assert_equal([+2, "\x01"+"\x00"*(w-1)], (+n+1).test_pack(numwords, wordsize, 0, TWOCOMP|LITTLE_ENDIAN))
        }
      }

      2.upto(16) {|wordsize|
        w = wordsize
        b = 8*wordsize-1
        n = 2**b
        assert_equal([-2, "\x7F"+"\xFF"*(w-2)+"\xFF"], (-n-1).test_pack(1, wordsize, 1, TWOCOMP|MSBYTE_FIRST))
        assert_equal([-1, "\x00"+"\x00"*(w-2)+"\x00"], (-n  ).test_pack(1, wordsize, 1, TWOCOMP|MSBYTE_FIRST))
        assert_equal([-1, "\x00"+"\x00"*(w-2)+"\x01"], (-n+1).test_pack(1, wordsize, 1, TWOCOMP|MSBYTE_FIRST))
        assert_equal([+1, "\x7F"+"\xFF"*(w-2)+"\xFF"], (+n-1).test_pack(1, wordsize, 1, TWOCOMP|MSBYTE_FIRST))
        assert_equal([+2, "\x00"+"\x00"*(w-2)+"\x00"], (+n  ).test_pack(1, wordsize, 1, TWOCOMP|MSBYTE_FIRST))
        assert_equal([+2, "\x00"+"\x00"*(w-2)+"\x01"], (+n+1).test_pack(1, wordsize, 1, TWOCOMP|MSBYTE_FIRST))
      }

      2.upto(16) {|wordsize|
        w = wordsize
        b = 8*wordsize-1
        n = 2**b
        assert_equal([-2, "\xFF"+"\xFF"*(w-2)+"\x7F"], (-n-1).test_pack(1, wordsize, 1, TWOCOMP|LSBYTE_FIRST))
        assert_equal([-1, "\x00"+"\x00"*(w-2)+"\x00"], (-n  ).test_pack(1, wordsize, 1, TWOCOMP|LSBYTE_FIRST))
        assert_equal([-1, "\x01"+"\x00"*(w-2)+"\x00"], (-n+1).test_pack(1, wordsize, 1, TWOCOMP|LSBYTE_FIRST))
        assert_equal([+1, "\xFF"+"\xFF"*(w-2)+"\x7F"], (+n-1).test_pack(1, wordsize, 1, TWOCOMP|LSBYTE_FIRST))
        assert_equal([+2, "\x00"+"\x00"*(w-2)+"\x00"], (+n  ).test_pack(1, wordsize, 1, TWOCOMP|LSBYTE_FIRST))
        assert_equal([+2, "\x01"+"\x00"*(w-2)+"\x00"], (+n+1).test_pack(1, wordsize, 1, TWOCOMP|LSBYTE_FIRST))
      }

    end

    def test_unpack_zero
      assert_equal(0, Integer.test_unpack("", 0, 1, 0, BIG_ENDIAN))
    end

    def test_unpack_argument_check
      assert_raise(ArgumentError) { Integer.test_unpack("x", 2, 1, 0, MSBYTE_FIRST) }
      assert_raise(ArgumentError) { Integer.test_unpack("x", 1, 1, 0, MSWORD_FIRST) }
      assert_raise(ArgumentError) { Integer.test_unpack("x", 1, 0, 0, BIG_ENDIAN) }
      assert_raise(ArgumentError) { Integer.test_unpack("x", 1, 1, 8, BIG_ENDIAN) }

      # assume sizeof(ssize_t) == sizeof(intptr_t)
      assert_raise(ArgumentError) { Integer.test_unpack("x", 1, 1 << ([""].pack("p").length * 8 - 1), 0, BIG_ENDIAN) }
    end

    def test_unpack_wordsize
      assert_equal(1, Integer.test_unpack("\x01", 1, 1, 0, BIG_ENDIAN))
      assert_equal(1, Integer.test_unpack("\x00\x01", 1, 2, 0, BIG_ENDIAN))
      assert_equal(1, Integer.test_unpack("\x00\x00\x01", 1, 3, 0, BIG_ENDIAN))
      assert_equal(1, Integer.test_unpack("\x01", 1, 1, 0, LITTLE_ENDIAN))
      assert_equal(1, Integer.test_unpack("\x01\x00", 1, 2, 0, LITTLE_ENDIAN))
      assert_equal(1, Integer.test_unpack("\x01\x00\x00", 1, 3, 0, LITTLE_ENDIAN))
    end

    def test_unpack_wordorder_and_endian
      assert_equal(0x01020304, Integer.test_unpack("\x01\x02\x03\x04", 2, 2, 0, MSWORD_FIRST|MSBYTE_FIRST))
      assert_equal(0x02010403, Integer.test_unpack("\x01\x02\x03\x04", 2, 2, 0, MSWORD_FIRST|LSBYTE_FIRST))
      assert_equal(0x03040102, Integer.test_unpack("\x01\x02\x03\x04", 2, 2, 0, LSWORD_FIRST|MSBYTE_FIRST))
      assert_equal(0x04030201, Integer.test_unpack("\x01\x02\x03\x04", 2, 2, 0, LSWORD_FIRST|LSBYTE_FIRST))
    end

    def test_unpack_native_endian
      assert_equal("\x12\x34".unpack("S!")[0], Integer.test_unpack("\x12\x34", 1, 2, 0, MSWORD_FIRST|NATIVE_BYTE_ORDER))
    end

    def test_unpack_nail
      assert_equal(0b100011, Integer.test_unpack("\x01\x00\x00\x00\x01\x01", 6, 1, 7, BIG_ENDIAN))
      assert_equal(0x12345678, Integer.test_unpack("\x01\x02\x03\x04\x05\x06\x07\x08", 8, 1, 4, BIG_ENDIAN))
      assert_equal(0x12345678, Integer.test_unpack("\x00\x12\x00\x34\x00\x56\x00\x78", 4, 2, 8, BIG_ENDIAN))
    end

    def test_unpack_sign
      assert_equal(-1, Integer.test_unpack("\x01", 1, 1, 0, BIG_ENDIAN|NEGATIVE))
      assert_equal(-0x8070605040302010, Integer.test_unpack("\x80\x70\x60\x50\x40\x30\x20\x10", 8, 1, 0, BIG_ENDIAN|NEGATIVE))
    end

    def test_unpack_orders
      [MSWORD_FIRST, LSWORD_FIRST].each {|word_order|
        [MSBYTE_FIRST, LSBYTE_FIRST, NATIVE_BYTE_ORDER].each {|byte_order|
          1.upto(16) {|wordsize|
            1.upto(20) {|numwords|
              w = numwords*wordsize
              ary = []
              0.upto(w) {|i|
                ary << ((i+1) % 256);
              }
              str = ary.pack("C*")
              flags = word_order|byte_order
              assert_equal(Integer.test_unpack(str, numwords, wordsize, 0, flags|GENERIC),
                           Integer.test_unpack(str, numwords, wordsize, 0, flags),
                          "Integer.test_unpack(#{str.dump}, #{numwords}, #{wordsize}, 0, #{'%#x' % flags})")
            }
          }
        }
      }
    end

    def test_unpack2comp_single_byte
      assert_equal(-128, Integer.test_unpack("\x80", 1, 1, 0, TWOCOMP|BIG_ENDIAN))
      assert_equal(  -2, Integer.test_unpack("\xFE", 1, 1, 0, TWOCOMP|BIG_ENDIAN))
      assert_equal(  -1, Integer.test_unpack("\xFF", 1, 1, 0, TWOCOMP|BIG_ENDIAN))
      assert_equal(   0, Integer.test_unpack("\x00", 1, 1, 0, TWOCOMP|BIG_ENDIAN))
      assert_equal(   1, Integer.test_unpack("\x01", 1, 1, 0, TWOCOMP|BIG_ENDIAN))
      assert_equal(   2, Integer.test_unpack("\x02", 1, 1, 0, TWOCOMP|BIG_ENDIAN))
      assert_equal( 127, Integer.test_unpack("\x7F", 1, 1, 0, TWOCOMP|BIG_ENDIAN))
    end

    def test_unpack2comp_sequence_of_ff
      assert_equal(-1, Integer.test_unpack("\xFF"*2, 2, 1, 0, TWOCOMP|BIG_ENDIAN))
      assert_equal(-1, Integer.test_unpack("\xFF"*3, 3, 1, 0, TWOCOMP|BIG_ENDIAN))
      assert_equal(-1, Integer.test_unpack("\xFF"*4, 4, 1, 0, TWOCOMP|BIG_ENDIAN))
      assert_equal(-1, Integer.test_unpack("\xFF"*5, 5, 1, 0, TWOCOMP|BIG_ENDIAN))
      assert_equal(-1, Integer.test_unpack("\xFF"*6, 6, 1, 0, TWOCOMP|BIG_ENDIAN))
      assert_equal(-1, Integer.test_unpack("\xFF"*7, 7, 1, 0, TWOCOMP|BIG_ENDIAN))
      assert_equal(-1, Integer.test_unpack("\xFF"*8, 8, 1, 0, TWOCOMP|BIG_ENDIAN))
      assert_equal(-1, Integer.test_unpack("\xFF"*9, 9, 1, 0, TWOCOMP|BIG_ENDIAN))
    end

    def test_unpack2comp_negative_single_byte
      assert_equal(-256, Integer.test_unpack("\x00", 1, 1, 0, TWOCOMP|BIG_ENDIAN|NEGATIVE))
      assert_equal(-255, Integer.test_unpack("\x01", 1, 1, 0, TWOCOMP|BIG_ENDIAN|NEGATIVE))
      assert_equal(-254, Integer.test_unpack("\x02", 1, 1, 0, TWOCOMP|BIG_ENDIAN|NEGATIVE))
      assert_equal(-129, Integer.test_unpack("\x7F", 1, 1, 0, TWOCOMP|BIG_ENDIAN|NEGATIVE))
      assert_equal(-128, Integer.test_unpack("\x80", 1, 1, 0, TWOCOMP|BIG_ENDIAN|NEGATIVE))
      assert_equal(  -2, Integer.test_unpack("\xFE", 1, 1, 0, TWOCOMP|BIG_ENDIAN|NEGATIVE))
      assert_equal(  -1, Integer.test_unpack("\xFF", 1, 1, 0, TWOCOMP|BIG_ENDIAN|NEGATIVE))
    end

    def test_unpack2comp_negative_zero
      0.upto(100) {|n|
        str = "\x00"*n
        flags = TWOCOMP|BIG_ENDIAN|NEGATIVE
        assert_equal(-(256**n), Integer.test_unpack(str, n, 1, 0, flags))
        flags = TWOCOMP|LITTLE_ENDIAN|NEGATIVE
        assert_equal(-(256**n), Integer.test_unpack(str, n, 1, 0, flags),
                    "Integer.test_unpack(#{str.dump}, #{n}, 1, 0, #{'%#x' % flags})")
      }
    end
  end

  def test_numbits_2comp
    assert_equal(4, -9.test_numbits_2comp_without_sign)
    assert_equal(3, -8.test_numbits_2comp_without_sign)
    assert_equal(3, -7.test_numbits_2comp_without_sign)
    assert_equal(3, -6.test_numbits_2comp_without_sign)
    assert_equal(3, -5.test_numbits_2comp_without_sign)
    assert_equal(2, -4.test_numbits_2comp_without_sign)
    assert_equal(2, -3.test_numbits_2comp_without_sign)
    assert_equal(1, -2.test_numbits_2comp_without_sign)
    assert_equal(0, -1.test_numbits_2comp_without_sign)
    assert_equal(0, 0.test_numbits_2comp_without_sign)
    assert_equal(1, 1.test_numbits_2comp_without_sign)
    assert_equal(2, 2.test_numbits_2comp_without_sign)
    assert_equal(2, 3.test_numbits_2comp_without_sign)
    assert_equal(3, 4.test_numbits_2comp_without_sign)
    assert_equal(3, 5.test_numbits_2comp_without_sign)
    assert_equal(3, 6.test_numbits_2comp_without_sign)
    assert_equal(3, 7.test_numbits_2comp_without_sign)
    assert_equal(4, 8.test_numbits_2comp_without_sign)
    assert_equal(4, 9.test_numbits_2comp_without_sign)
  end

  def test_numbytes_2comp
    assert_equal(6, -0x8000000001.test_numbytes_2comp_with_sign)
    assert_equal(5, -0x8000000000.test_numbytes_2comp_with_sign)
    assert_equal(5, -0x80000001.test_numbytes_2comp_with_sign)
    assert_equal(4, -0x80000000.test_numbytes_2comp_with_sign)
    assert_equal(4, -0x800001.test_numbytes_2comp_with_sign)
    assert_equal(3, -0x800000.test_numbytes_2comp_with_sign)
    assert_equal(3, -0x8001.test_numbytes_2comp_with_sign)
    assert_equal(2, -0x8000.test_numbytes_2comp_with_sign)
    assert_equal(2, -0x81.test_numbytes_2comp_with_sign)
    assert_equal(1, -0x80.test_numbytes_2comp_with_sign)
    assert_equal(1, -1.test_numbytes_2comp_with_sign)
    assert_equal(1, 0.test_numbytes_2comp_with_sign)
    assert_equal(1, 1.test_numbytes_2comp_with_sign)
    assert_equal(1, 0x7f.test_numbytes_2comp_with_sign)
    assert_equal(2, 0x80.test_numbytes_2comp_with_sign)
    assert_equal(2, 0x7fff.test_numbytes_2comp_with_sign)
    assert_equal(3, 0x8000.test_numbytes_2comp_with_sign)
    assert_equal(3, 0x7fffff.test_numbytes_2comp_with_sign)
    assert_equal(4, 0x800000.test_numbytes_2comp_with_sign)
    assert_equal(4, 0x7fffffff.test_numbytes_2comp_with_sign)
    assert_equal(5, 0x80000000.test_numbytes_2comp_with_sign)
    assert_equal(5, 0x7fffffffff.test_numbytes_2comp_with_sign)
    assert_equal(6, 0x8000000000.test_numbytes_2comp_with_sign)
  end

end