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Extracted calculateLuhnChecksum() and calculateXorChecksum()

This commit is contained in:
dankl 2019-10-30 22:55:37 +01:00 committed by dankito
parent 2c5f14df6a
commit c7e71fcc84
1 changed files with 32 additions and 17 deletions
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49
fints4javaLib/src/main/kotlin/net/dankito/fints/tan/FlickercodeDecoder.kt
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@ -21,18 +21,7 @@ open class FlickercodeDecoder {
val de2 = parseDatenelement(challengeHHD_UC, de1.endIndex)
val de3 = parseDatenelement(challengeHHD_UC, de2.endIndex)
val luhnData = controlByte + startCode + de1.data + de2.data + de3.data
val luhnSum = luhnData.mapIndexed { index, char ->
val asNumber = char.toString().toInt(16)
if (index % 2 == 1) {
val doubled = asNumber * 2
return@mapIndexed (doubled / 10) + (doubled % 10)
}
asNumber
}.sum()
val luhnChecksum = calculateLuhnChecksum(startCode, controlByte, de1, de2, de3)
// TODO:
// können im HHDUC-Protokoll Datenelemente ausgelassen werden, indem als Länge LDE1, LDE2 oder LDE3 = ‘00‘ angegeben wird.
@ -43,11 +32,7 @@ open class FlickercodeDecoder {
val dataLength = (dataWithoutLengthAndChecksum.length + 2) / 2 // + 2 for checksum
val dataWithoutChecksum = toHex(dataLength, 2) + dataWithoutLengthAndChecksum
var xorChecksum = 0
val xorByteData = dataWithoutChecksum.map { parseIntToHex(it) }
xorByteData.forEach { xorChecksum = xorChecksum xor it }
val xorChecksumString = toHex(xorChecksum, 1)
val xorChecksumString = calculateXorChecksum(dataWithoutChecksum)
val parsedDataSet = dataWithoutChecksum + luhnChecksum + xorChecksumString
@ -121,6 +106,36 @@ open class FlickercodeDecoder {
return lengthByte and 0b00011111
}
protected open fun calculateLuhnChecksum(startCode: FlickercodeDatenelement, controlByte: String,
de1: FlickercodeDatenelement, de2: FlickercodeDatenelement, de3: FlickercodeDatenelement): Int {
val luhnData = controlByte + startCode.data + de1.data + de2.data + de3.data
val luhnSum = luhnData.mapIndexed { index, char ->
val asNumber = char.toString().toInt(16)
if (index % 2 == 1) {
val doubled = asNumber * 2
return@mapIndexed (doubled / 10) + (doubled % 10)
}
asNumber
}.sum()
return 10 - (luhnSum % 10)
}
protected open fun calculateXorChecksum(dataWithoutChecksum: String): String {
var xorChecksum = 0
val xorByteData = dataWithoutChecksum.map { parseIntToHex(it) }
xorByteData.forEach { xorChecksum = xorChecksum xor it }
return toHex(xorChecksum, 1)
}
protected open fun toHex(number: Int, minLength: Int): String {
var result = number.toString (16).toUpperCase()