kotlin-stdlib/kotlin.text/HexFormat/BytesHexFormat/Builder/bytePrefix

bytePrefix

var bytePrefix: String(source)

Defines BytesHexFormat.bytePrefix of the format being built, empty string by default.

The string must not contain line feed (LF) and carriage return (CR) characters.

Refer to BytesHexFormat.bytePrefix for details about how this format option affects the formatting and parsing results.

Since Kotlin

1.9

Throws

if a string containing LF or CR character is assigned to this property.

Samples

import kotlin.test.*

fun main() { 
   //sampleStart 
   val data = ByteArray(4) { it.toByte() }

// By default, the bytePrefix is an empty string, so bytes are formatted without any prefix.
println(data.toHexString()) // 00010203
println("\"00010203\".hexToByteArray().contentEquals(data) is ${"00010203".hexToByteArray().contentEquals(data)}") // true

// Specifying a custom byte prefix, "0x" in this case, to precede each byte.
// A space is used as a byte separator for clarity in the output.
val bytePrefixFormat = HexFormat {
    bytes.bytePrefix = "0x"
    bytes.byteSeparator = " "
}
println(data.toHexString(bytePrefixFormat)) // 0x00 0x01 0x02 0x03
println("\"0x00 0x01 0x02 0x03\".hexToByteArray(bytePrefixFormat).contentEquals(data) is ${"0x00 0x01 0x02 0x03".hexToByteArray(bytePrefixFormat).contentEquals(data)}") // true

// Parsing fails due to incorrect byte prefix.
// In this case, the input string is lacking the necessary byte prefixes.
// "00 01 02 03".hexToByteArray(bytePrefixFormat) // will fail with IllegalArgumentException 
   //sampleEnd
}