io.github.binaryfoo.decoders.ByteLabeller.kt Maven / Gradle / Ivy

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Some decoders for the data used in EMV credit card transactions.

There is a newer version: 0.1.8

package io.github.binaryfoo.decoders

import io.github.binaryfoo.DecodedData
import io.github.binaryfoo.Decoder
import io.github.binaryfoo.bit.fromHex
import java.util.*

/**
 * Decode and label bits in a string according to the EMV spec convention.
 */
class ByteLabeller : Decoder {
    override fun decode(input: String, startIndexInBytes: Int, session: DecodeSession): List {
        val decoded = ArrayList()
        for (bit in fromHex(input)) {
            val byteIndex = startIndexInBytes + bit.byteNumber - 1
            decoded.add(DecodedData.primitive(bit.toString(), "", byteIndex, byteIndex + 1))
        }
        return decoded
    }

    override fun validate(input: String?): String? {
        if (input != null && (input.length % 2) != 0) {
            return "Must be an even number of characters"
        }
        return null
    }

    override fun getMaxLength(): Int = Integer.MAX_VALUE
}