reline_mbchar_width_performance.rb

# https://github.com/ruby/reline/pull/632

sizes=[]
CHUNK_LAST.zip(CHUNK_WIDTH).each{sizes << _2 while sizes.size <= [_1, 0x10ffff].min };
BITCHUNKS = sizes.each_slice(2048).map do |seg|
  next seg.first if seg.uniq.size == 1
  seg.each_slice(64).map do |sub|
    next sub.first if sub.uniq.size == 1
    s = sub.map { _1 == -1 ? 3 : _1 }.reverse.join
    num = s.to_i(4)
    num <= 2 ? ('1' + s).to_i(4) : num
  end
end

def get_mbchar_width2(m)
  ord = m.ord
  a = BITCHUNKS[ord / 2048]
  return a if a.is_a?(Integer)
  ord %= 2048
  b = a[ord / 64]
  return b if b <= 2
  c = b[ord % 64 * 2, 2]
  c == 3 ? -1 : c
end

def get_mbchar_width(mbchar)
  ord = mbchar.ord
  chunk_index = CHUNK_LAST.bsearch_index { |o| ord <= o }
  size = CHUNK_WIDTH[chunk_index]
  size
end