Kotlin Native how to convert ByteArray to String? – Kotlin

The Problem:

In Kotlin Native, you are working with a ByteArray that contains binary data and want to convert it to a String for printing or further processing. You know that the ByteArray is pinned in memory, which means it is safe to access directly, but you need to find a way to decode the binary data into a human-readable format.

The Solutions:

Solution 1: Use `stringFromUtf8`

To convert a ByteArray to a String in Kotlin Native, use the `stringFromUtf8` method.

The `stringFromUtf8` method takes two optional parameters:
`start` and `size`. The `start` parameter specifies the index of the first byte in the ByteArray to include in the String. The `size` parameter specifies the number of bytes to include in the String. If you do not specify these parameters, the entire ByteArray will be converted to a String.

For example, the following code converts the entire ByteArray to a String:

val byteArray = byteArrayOf(1, 2, 3, 4, 5)
val string = byteArray.stringFromUtf8()

The `string` variable will now contain the String “12345”.

Solution 2: Use `toKString()`

If the ByteArray is like `CPointer` by interoperating C APIs, you can use the `.toKString()` method in Kotlin-Native.

The `.toKString()` method will convert the ByteArray to a String using the UTF-8 encoding.

For example, the following code converts the ByteArray to a String using the `.toKString()` method:

val byteArray = CPointer<ByteVar>(1, 2, 3, 4, 5)
val string = byteArray.toKString()

The `string` variable will now contain the String “12345”.

Solution 2: Convert ByteArray to String on the JVM

For the JVM, one can use `toString()` with a `Charset` argument to convert a `ByteArray` to a `String`. Here’s an example:

“`
val byteArray = “Hello World”.toByteArray(Charsets.UTF_8)

val str = byteArray.toString(Charsets.UTF_8)
println(str) // Prints "Hello World"

<p>This method uses the specified `Charset` to decode the bytes in the `ByteArray` into a `String`. The `Charsets.UTF_8` constant represents the UTF-8 character encoding, which is widely used on the web and in many applications.</p>

Solution 3: ByteArray.toString(Charsets.UTF_8)

The ByteArray.toString(Charsets.UTF_8) method can be used to convert a ByteArray to a String. This method takes a Charset as an argument, which specifies the character encoding to use. In this case, we are using the UTF-8 character encoding, which is a widely used encoding that can represent most characters in the world’s languages.

To use the ByteArray.toString(Charsets.UTF_8) method, you can simply call it on your ByteArray object. For example:

val byteArray = byteArrayOf(65, 66, 67)
val string = byteArray.toString(Charsets.UTF_8)

This code will convert the ByteArray containing the ASCII codes for the letters “ABC” into a String containing the string “ABC”.

Solution 4: Convert ByteArray to String using Okio library

The Okio library provides a helper method called commonToUtf8String() that converts a ByteArray to a String. To use this method, you can follow these steps:

1. Copy the code for the commonToUtf8String() method from the Okio library.
2. In your Kotlin Native code, create a ByteArray variable that contains the data you want to convert to a string.
3. Call the commonToUtf8String() method on the ByteArray variable to convert it to a String.
4. Use the resulting String variable as needed.

Here is an example of how to use the commonToUtf8String() method to convert a ByteArray to a String in Kotlin Native:


import okio.Buffer
import okio.ByteString

// Convert the ByteArray to a String using the commonToUtf8String() method.
val string = bytes.commonToUtf8String()

// Print the String to the console.
println(string)

}


This code will output the following to the console:


Hello World