count_words.cr

#!/usr/bin/env crystal run

buf = Bytes.new 4096
ints = Slice(UInt64).new(buf.pointer(4096).as(UInt64*), buf.size / sizeof(UInt64))

words = 1
lines = 0
bytes_total = 0

while (bytes = ARGF.read buf) > 0
  bytes_total += bytes

  if bytes != buf.size # Slow path?
    buf.each do |byte|
      words += 1 if byte == 0x20
    end
  else
    ints.each do |qword|
      v = qword ^ (UInt64::MAX / 0xFFu64 * 0x20u64)
      if ((v - 0x0101010101010101u64) & ~v & 0x8080808080808080u64) > 0
        words += (v & 0xFF00000000000000u64 == 0).hash
        words += (v & 0x00FF000000000000u64 == 0).hash
        words += (v & 0x0000FF0000000000u64 == 0).hash
        words += (v & 0x000000FF00000000u64 == 0).hash
        words += (v & 0x00000000FF000000u64 == 0).hash
        words += (v & 0x0000000000FF0000u64 == 0).hash
        words += (v & 0x000000000000FF00u64 == 0).hash
        words += (v & 0x00000000000000FFu64 == 0).hash
      end
    end
  end
end

pp words, lines, bytes_total

words       # => 17712435
lines       # => 0
bytes_total # => 104857408
./wc foo  0,04s user 0,02s system 95% cpu 0,059 total

        0  17712400 104857408 foo
wc foo  0,88s user 0,01s system 99% cpu 0,901 total