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kotlinlang

How do you convert `ByteArray` to and from `CFDataRef`? I found <https://gist.github.com/noahsark769/61cfb7a8b7231e2069a9dab94cf74a62|this> for converting to/from `NSData`, but having a hard time figuring out how to do something similar for `CFDataRef`. I need to create a `SecCertificateRef`, which I’m using `SecCertificateCreateWithData()` and `SecCertificateCopyData()` to create and get the data from.

I came up with this:
```fun CFDataRef.toByteArray(): ByteArray {
    val length = CFDataGetLength(this)
    return UByteArray(length.toInt()).apply {
        val range = CFRangeMake(0, length)
        CFDataGetBytes(this@toByteArray, range, refTo(0))
    }.toByteArray()
}```
Is it required to create a `UByteArray` first or can the `refTo()` of `ByteArray` be safely cast from `CValueRef&lt;ByteVarOf&lt;Byte&gt;&gt;` to the `CValuesRef&lt;UByteVarOf&lt;UByte&gt;&gt;` that `CFDataGetBytes()` requires?

And for the conversion to:
```fun ByteArray.toCFData(): CFDataRef =
        CFDataCreate(null,
                toUByteArray().refTo(0),
                size.toLong())!!```
Same question about the need to convert to `UByteArray`, or if casting the address would work without needing to copy data twice.

Am I on the right track with these?

After some testing, these routines seem to work. I just replaced `toUByteArray()` and `toByteArray()` with `asUByteArray()` and `asByteArray()` to avoid the extra copy.