Detect line break, new line (CR, LF, CRLF)

detectLineBreak.go

const (
  lineUnknown = "unkown"
  lineLF      = "LF" // 0x0A
  lineCR      = "CR" // 0x0D
  lineCRLF    = lineLF + lineCR
)

const (
  byteLF = 0x0A
  byteCR = 0x0D
)

func detectLineBreak(cnt []byte) string {
  pos := 0
  for pos < len(cnt) {
    a := cnt[pos]
    var b byte
    if pos+1 < len(cnt) {
      b = cnt[pos+1]
    }

    if a == byteCR && b == byteLF {
      return lineCRLF
    } else if a == byteCR && b != byteLF {
      return lineCR
    } else if a == byteLF || b == byteLF {
      return lineLF
    }

    if b == byteCR {
      pos++
    } else {
      pos += 2
    }
  }
  return lineUnknown
}