private static unsafe int?IndexOfCharacterThatNeedsEscaping(Utf8Span utf8Span)
{
int vectorCount = Vector <byte> .Count;
int index = 0;
// If we can benefit from SIMD scan, use that approach
if (Vector.IsHardwareAccelerated)
{
// Ensure we stop the SIMD scan before the length of the vector would
// go past the end of the array
#pragma warning disable IDE0047 // Remove unnecessary parentheses
int lastVectorMultiple = (utf8Span.Length / vectorCount) * vectorCount;
#pragma warning restore IDE0047 // Remove unnecessary parentheses
for (; index < lastVectorMultiple; index += vectorCount)
{
Vector <byte> vector;
unsafe
{
fixed(byte *spanPtr = utf8Span.Span)
{
vector = Unsafe.Read <Vector <byte> >(spanPtr + index);
}
}
if (JsonTextWriter.HasCharacterThatNeedsEscaping(vector))
{
// The Vector contained a character that needed escaping
// Loop to find the exact character and index
for (; index < utf8Span.Length; ++index)
{
byte c = utf8Span.Span[index];
if (JsonTextWriter.NeedsEscaping(c))
{
return(index);
}
}
}
}
}
// Unless the scan ended on a vectorCount multiple,
// still need to check the last few characters
for (; index < utf8Span.Length; ++index)
{
byte c = utf8Span.Span[index];
if (JsonTextWriter.NeedsEscaping(c))
{
return(index);
}
}
return(null);
}
