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unless Range.method_defined? :bsearch
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
map = Proc.new do |pk, unpk, nb|
result, = [nb.abs].pack(pk).unpack(unpk)
nb < 0 ? -result : result
end
from = map['D', 'q', to.to_f]
to = map['D', 'q', to.to_f]
convert = Proc.new{ map['q', 'D', 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
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