kotlin-stdlib/kotlin.io.encoding/Base64/decode

decode

fun decode(source: ByteArray, startIndex: Int = 0, endIndex: Int = source.size): ByteArray(source)

Decodes symbols from the specified source array or its subrange. Returns a ByteArray containing the resulting bytes.

The requirement, prohibition, or optionality of padding in the input symbols is determined by the PaddingOption set for this Base64 instance.

Since Kotlin

1.8

Return

a ByteArray with the resulting bytes.

Parameters

source

the array to decode symbols from.

startIndex

the beginning (inclusive) of the subrange to decode, 0 by default.

endIndex

the end (exclusive) of the subrange to decode, size of the source array by default.

Throws

when startIndex or endIndex is out of range of source array indices.

when the symbols for decoding are not padded as required by the PaddingOption set for this Base64 instance, or when there are extra symbols after the padding.

Samples

import kotlin.io.encoding.*
import kotlin.test.*

fun main() { 
   //sampleStart 
   // get a byte array filled with data, for instance, by reading it from a network
val data = byteArrayOf(0x61, 0x47, 0x56, 0x73, 0x62, 0x47, 0x38, 0x3d)
// decode data from the array
println("Base64.decode(data).contentEquals(\"hello\".encodeToByteArray()) is ${Base64.decode(data).contentEquals("hello".encodeToByteArray())}") // true

val dataInTheMiddle = byteArrayOf(0x00, 0x00, 0x61, 0x47, 0x56, 0x73, 0x62, 0x47, 0x38, 0x3d, 0x00, 0x00)
// decode base64-encoded data from the middle of a buffer
val decoded = Base64.decode(dataInTheMiddle, startIndex = 2, endIndex = 10)
println("decoded.contentEquals(\"hello\".encodeToByteArray()) is ${decoded.contentEquals("hello".encodeToByteArray())}") // true 
   //sampleEnd
}
fun decode(source: CharSequence, startIndex: Int = 0, endIndex: Int = source.length): ByteArray(source)

Decodes symbols from the specified source char sequence or its substring. Returns a ByteArray containing the resulting bytes.

The requirement, prohibition, or optionality of padding in the input symbols is determined by the PaddingOption set for this Base64 instance.

Since Kotlin

1.8

Return

a ByteArray with the resulting bytes.

Parameters

source

the char sequence to decode symbols from.

startIndex

the beginning (inclusive) of the substring to decode, 0 by default.

endIndex

the end (exclusive) of the substring to decode, length of the source by default.

Throws

when startIndex or endIndex is out of range of source indices.

when the symbols for decoding are not padded as required by the PaddingOption set for this Base64 instance, or when there are extra symbols after the padding.

Samples

import kotlin.io.encoding.*
import kotlin.test.*

fun main() { 
   //sampleStart 
   println("Base64.decode(\"/wD+AP0=\").contentEquals(byteArrayOf(-1, 0, -2, 0, -3)) is ${Base64.decode("/wD+AP0=").contentEquals(byteArrayOf(-1, 0, -2, 0, -3))}") // true

val embeddedB64 = "Data is: \"/wD+AP0=\""
// find '"' indices and extract base64-encoded data in between
val decoded = Base64.decode(
    embeddedB64,
    startIndex = embeddedB64.indexOf('"') + 1,
    endIndex = embeddedB64.lastIndexOf('"')
)
println("decoded.contentEquals(byteArrayOf(-1, 0, -2, 0, -3)) is ${decoded.contentEquals(byteArrayOf(-1, 0, -2, 0, -3))}") // true 
   //sampleEnd
}