Method classifyDataModes

encoder.go:219–254

classifyDataModes classifies the raw data into unoptimised segments. e.g. "123ZZ#!#!" => [numeric, 3, "123"] [alphanumeric, 2, "ZZ"] [byte, 4, "#!#!"]. Returns the highest data mode needed to encode the data. e.g. for a mixed numeric/alphanumeric input, the highest is alphanumeric. dataModeNone <

()

//
// dataModeNone < dataModeNumeric < dataModeAlphanumeric < dataModeByte
func (d *dataEncoder) classifyDataModes() dataMode {
	var start int
	mode := dataModeNone
	highestRequiredMode := mode

	for i, v := range d.data {
		newMode := dataModeNone
		switch {
		case v >= 0x30 && v <= 0x39:
			newMode = dataModeNumeric
		case v == 0x20 || v == 0x24 || v == 0x25 || v == 0x2a || v == 0x2b || v ==
			0x2d || v == 0x2e || v == 0x2f || v == 0x3a || (v >= 0x41 && v <= 0x5a):
			newMode = dataModeAlphanumeric
		default:
			newMode = dataModeByte
		}

		if newMode != mode {
			if i > 0 {
				d.actual = append(d.actual, segment{dataMode: mode, data: d.data[start:i]})

				start = i
			}

			mode = newMode
		}

		if newMode > highestRequiredMode {
			highestRequiredMode = newMode
		}
	}

	d.actual = append(d.actual, segment{dataMode: mode, data: d.data[start:len(d.data)]})

	return highestRequiredMode
}

// optimiseDataModes optimises the list of segments to reduce the overall output
// encoded data length.