io.github.binaryfoo.RootDecoder.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

import io.github.binaryfoo.decoders.*
import io.github.binaryfoo.decoders.apdu.*
import io.github.binaryfoo.tlv.CommonVendorErrorMode
import io.github.binaryfoo.tlv.Tag
import io.github.binaryfoo.tlv.TagRecognitionMode
import kotlin.collections.linkedMapOf
import kotlin.collections.toTypedArray

/**
 * The main entry point.
 */
class RootDecoder {

    /**
     * f(hex string) -> somewhat english description
     *
     * @param value Hex string to decode.
     * @param meta One of the keys in io.github.binaryfoo.RootDecoder#TAG_META_SETS.
     * @param tagInfo One of the values returned by io.github.binaryfoo.RootDecoder#getTagInfo(java.lang.String).
     *
     * @return Somewhat english description.
     */
    fun decode(value: String, meta: String, tagInfo: TagInfo, tagRecognitionMode: TagRecognitionMode = CommonVendorErrorMode): List {
        val decodeSession = DecodeSession()
        decodeSession.tagMetaData = getTagMetaData(meta)
        decodeSession.tagRecognitionMode = tagRecognitionMode
        return tagInfo.decoder.decode(value, 0, decodeSession)
    }

    fun decode(value: String, meta: String, tag: String): List {
        return decode(value, meta, getTagInfo(tag)!!)
    }

    fun getTagMetaData(meta: String): TagMetaData {
        return TAG_META_SETS[meta] ?: EmvTags.METADATA
    }

    companion object {
        private val TAG_META_SETS = linkedMapOf(
            "EMV" to EmvTags.METADATA,
            "qVSDC" to QVsdcTags.METADATA,
            "MSD" to MSDTags.METADATA,
            "Amex" to AmexTags.METADATA,
            "UPI" to UpiTags.METADATA
        )
        private val ROOT_TAG_INFO = linkedMapOf(
            EmvTags.TERMINAL_VERIFICATION_RESULTS to EmvTags.METADATA,
            EmvTags.TSI to EmvTags.METADATA,
            EmvTags.APPLICATION_INTERCHANGE_PROFILE to EmvTags.METADATA,
            EmvTags.CVM_LIST to EmvTags.METADATA,
            EmvTags.CVM_RESULTS to EmvTags.METADATA,
            QVsdcTags.CARD_TX_QUALIFIERS to QVsdcTags.METADATA,
            QVsdcTags.TERMINAL_TX_QUALIFIERS to QVsdcTags.METADATA,
            "dol" to TagInfo.treeStructured("DOL", "Data Object List", DataObjectListDecoder(), shortBackground = "A list of (tag name, expected length) pairs"),
            "constructed" to TagInfo.treeStructured("TLV Data", "Constructed TLV data", TLVDecoder(), shortBackground = "A hex string encoding of a list of Tag, Length, Value objects"),
            "apdu-sequence" to TagInfo.treeStructured("APDUs", "Sequence of Command/Reply APDUs", APDUSequenceDecoder(ReplyAPDUDecoder(TLVDecoder()),
                    SelectCommandAPDUDecoder(), GetProcessingOptionsCommandAPDUDecoder(), ReadRecordAPDUDecoder(), GenerateACAPDUDecoder(), GetDataAPDUDecoder(),
                    ExternalAuthenticateAPDUDecoder(), ComputeCryptoChecksumDecoder(), InternalAuthenticateAPDUDecoder(), VerifyPinAPDUDecoder(), GetChallengeAPDUDecoder(), PutDataAPDUDecoder(),
                    ReadBinaryAPDUDecoder()),
                    shortBackground = "A hex string encoded trace.",
                    longBackground = "Each line should be a hex string encoding of either a Command or Response APDU."),
            "bit-string" to TagInfo.treeStructured("Bits", "EMV Bit String", ByteLabeller(), shortBackground = "Uses the EMV convention: bytes left to right, bits right to left."),
            "filled-dol" to TagInfo.treeStructured("Filled DOL", "Data Object List", PopulatedDOLDecoder(), "Two lines: 1st is a DOL. 2nd the values to populate it with.")
        )

        private infix fun Tag.to(that: TagMetaData): Pair = Pair(this.hexString, that.get(this))

        @JvmStatic fun getTagInfo(tag: String): TagInfo? {
            return ROOT_TAG_INFO[tag]
        }

        // array because List and friends seem to show up in .java as List