// TODO: this should be moved to System.Text.Primitives. Probably to Utf8 class
static string Utf8ToString(ReadOnlySpan <byte> utf8)
{
var result = Utf8.ToUtf16Length(utf8, out int bytesNeeded);
if (result == TransformationStatus.InvalidData || result == TransformationStatus.NeedMoreSourceData)
{
throw new Exception("invalid UTF8 byte");
}
var str = new string(' ', bytesNeeded / sizeof(char));
unsafe
{
fixed(char *pStr = str)
{
var strSpan = new Span <char>(pStr, str.Length);
if (Utf8.ToUtf16(utf8, strSpan.AsBytes(), out int consumed, out int written) != TransformationStatus.Done)
{
throw new Exception();
}
}
}
return(str);
}
/// <summary> /// Calculates the byte count needed to encode the UTF-16 bytes from the specified UTF-8 sequence. /// /// This method will consume as many of the input bytes as possible. /// </summary> /// <param name="source">A span containing a sequence of UTF-8 bytes.</param> /// <param name="bytesNeeded">On exit, contains the number of bytes required for encoding from the <paramref name="source"/>.</param> /// <returns>A <see cref="OperationStatus"/> value representing the expected state of the conversion.</returns> public static OperationStatus FromUtf8Length(ReadOnlySpan <byte> source, out int bytesNeeded) => Utf8.ToUtf16Length(source, out bytesNeeded);