hexToLong

import kotlin.test.*

fun main() { 
   //sampleStart 
   // Using the default format
println("3a".hexToLong()) // 58

// Parsing is case-insensitive
println("3A".hexToLong()) // 58

// Up to 16 hexadecimal digits can fit into a Long
println("ffffffffffffffff".hexToLong()) // -1

// Excess leading hexadecimal digits must be zeros
println("00ffffffffffffffff".hexToLong()) // -1
// "010000000000000000".hexToLong() // will fail with IllegalArgumentException

// Parsing an ULong results in the unsigned version of the same value
// In this case, (-1L).toULong() = ULong.MAX_VALUE
println("ffffffffffffffff".hexToULong()) // 18446744073709551615

// Using a custom format
val format = HexFormat { number.prefix = "0x" }
println("0x3A".hexToLong(format)) // 58

// Parsing fails if the input string does not conform to the specified format.
// In this case, the prefix is not present.
// "3A".hexToLong(format) // will fail with IllegalArgumentException 
   //sampleEnd
}