public static unsafe int NeedsEscaping(ReadOnlySpan <char> value, JavaScriptEncoder encoder)
{
int idx;
// Some implementations of JavascriptEncoder.FindFirstCharacterToEncode may not accept
// null pointers and gaurd against that. Hence, check up-front and fall down to return -1.
if (encoder != null && !value.IsEmpty)
{
fixed(char *ptr = value)
{
idx = encoder.FindFirstCharacterToEncode(ptr, value.Length);
}
goto Return;
}
for (idx = 0; idx < value.Length; idx++)
{
if (NeedsEscaping(value[idx]))
{
goto Return;
}
}
idx = -1; // all characters allowed
Return:
return(idx);
}
public static unsafe int NeedsEscaping(ReadOnlySpan <char> value, JavaScriptEncoder encoder)
{
fixed(char *ptr = value)
{
int idx = 0;
// Some implementations of JavascriptEncoder.FindFirstCharacterToEncode may not accept
// null pointers and gaurd against that. Hence, check up-front and fall down to return -1.
if (encoder != null && !value.IsEmpty)
{
idx = encoder.FindFirstCharacterToEncode(ptr, value.Length);
goto Return;
}
#if BUILDING_INBOX_LIBRARY
if (Sse2.IsSupported)
{
short *startingAddress = (short *)ptr;
while (value.Length - 8 >= idx)
{
Debug.Assert(startingAddress >= ptr && startingAddress <= (ptr + value.Length - 8));
// Load the next 8 characters.
Vector128 <short> sourceValue = Sse2.LoadVector128(startingAddress);
// Check if any of the 8 characters need to be escaped.
Vector128 <short> mask = CreateEscapingMask(sourceValue);
int index = Sse2.MoveMask(mask.AsByte());
// If index == 0, that means none of the 8 characters needed to be escaped.
// TrailingZeroCount is relatively expensive, avoid it if possible.
if (index != 0)
{
// Found at least one character that needs to be escaped, figure out the index of
// the first one found that needed to be escaped within the 8 characters.
Debug.Assert(index > 0 && index <= 65_535);
int tzc = BitOperations.TrailingZeroCount(index);
Debug.Assert(tzc % 2 == 0 && tzc >= 0 && tzc <= 16);
idx += tzc >> 1;
goto Return;
}
idx += 8;
startingAddress += 8;
}
// Process the remaining characters.
Debug.Assert(value.Length - idx < 8);
}
#endif
for (; idx < value.Length; idx++)
{
Debug.Assert((ptr + idx) <= (ptr + value.Length));
if (NeedsEscaping(*(ptr + idx)))
{
goto Return;
}
}
idx = -1; // All characters are allowed.
Return:
return(idx);
}
}