module TTFunk::BinUtils
Bit crunching utility methods.
Public Instance Methods
Source
# File lib/ttfunk/bin_utils.rb, line 58 def rangify(values) values .slice_when { |a, b| b - a > 1 } .map { |span| [span.first, span.length - 1] } end
Turns a (sorted) sequence of values into a series of two-element arrays where the first element is the start and the second is the length.
@param values [Array<Integer>] @return [Array<Array(Integer, Integer)>]
Source
# File lib/ttfunk/bin_utils.rb, line 28 def slice_int(value, bit_width:, slice_count:) mask = (2**bit_width) - 1 Array.new(slice_count) do |i| (value >> (bit_width * i)) & mask end end
Slice a big integer into a bunch of small integers. Assumes big-endian.
@param value [Integer] @param bit_width [Integer] bit width of the elements @param slice_count [Integer] number of elements to slice into. This is
needed for cases where top bits are zero.
@return [Array<Integer>]
Source
# File lib/ttfunk/bin_utils.rb, line 11 def stitch_int(arr, bit_width:) value = 0 arr.each_with_index do |element, index| value |= element << (bit_width * index) end value end
Turn a bunch of small integers into one big integer. Assumes big-endian.
@param arr [Array<Integer>] @param bit_width [Integer] bit width of the elements @return [Integer]
Source
# File lib/ttfunk/bin_utils.rb, line 41 def twos_comp_to_int(num, bit_width:) if num >> (bit_width - 1) == 1 # we want all ones mask = (2**bit_width) - 1 # find 2's complement, i.e. flip bits (xor with mask) and add 1 -((num ^ mask) + 1) else num end end
Two’s compliment to an integer.
@param num [Integer] @param bit_width [Integer] number width @return [Integer]