kotlinx.serialization.csv.decode.CollectionRecordCsvDecoder.kt Maven / Gradle / Ivy

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package kotlinx.serialization.csv.decode

import kotlinx.serialization.ExperimentalSerializationApi
import kotlinx.serialization.csv.Csv
import kotlinx.serialization.descriptors.SerialDescriptor
import kotlinx.serialization.encoding.CompositeDecoder.Companion.DECODE_DONE

/**
 * Decode collection record.
 *
 * If the CSV record is a collection (list, set, map) the collection elements fill the whole line.
 * Therefore, the number of elements is determined by reading until the end of line and the size of the collection is
 * not required and consequently not expected as the first value.
 */
@OptIn(ExperimentalSerializationApi::class)
internal class CollectionRecordCsvDecoder(
    csv: Csv,
    reader: CsvReader,
    parent: RecordListCsvDecoder
) : CsvDecoder(csv, reader, parent) {

    private var elementIndex = 0

    private val recordNo = reader.recordNo

    override fun decodeElementIndex(descriptor: SerialDescriptor): Int = when {
        // TODO Check for END_OF_RECORD
        reader.isDone || reader.recordNo != recordNo -> DECODE_DONE
        else -> elementIndex
    }

    override fun endChildStructure(descriptor: SerialDescriptor) {
        super.endChildStructure(descriptor)
        elementIndex++
    }

    override fun decodeColumn(): String {
        val value = super.decodeColumn()
        elementIndex++
        return value
    }
}