unless Range.method_defined? :bsearch require 'backports/tools/float_integer_conversion' class Range def bsearch return to_enum(:bsearch) unless block_given? from = self.begin to = self.end unless from.is_a?(Numeric) && to.is_a?(Numeric) raise TypeError, "can't do binary search for #{from.class}" end midpoint = nil if from.is_a?(Integer) && to.is_a?(Integer) convert = Proc.new{ midpoint } else from = Backports.float_to_integer(from.to_f) to = Backports.float_to_integer(to.to_f) convert = Proc.new{ Backport.integer_to_float(midpoint) } end to -= 1 if exclude_end? satisfied = nil while from <= to do midpoint = (from + to).div(2) result = yield(cur = convert.call) case result when Numeric return cur if result == 0 result = result < 0 when true satisfied = cur when nil, false # nothing to do else raise TypeError, "wrong argument type #{result.class} (must be numeric, true, false or nil)" end if result to = midpoint - 1 else from = midpoint + 1 end end satisfied end end end