private static int EscapeNextBytes(ReadOnlySpan <byte> value, Span <byte> destination, ref int written)
{
SequenceValidity status = PeekFirstSequence(value, out int numBytesConsumed, out int scalar);
if (status != SequenceValidity.WellFormed)
{
ThrowHelper.ThrowArgumentException_InvalidUTF8(value);
}
destination[written++] = (byte)'\\';
switch (scalar)
{
case JsonConstants.LineFeed:
destination[written++] = (byte)'n';
break;
case JsonConstants.CarriageReturn:
destination[written++] = (byte)'r';
break;
case JsonConstants.Tab:
destination[written++] = (byte)'t';
break;
case JsonConstants.BackSlash:
destination[written++] = (byte)'\\';
break;
case JsonConstants.BackSpace:
destination[written++] = (byte)'b';
break;
case JsonConstants.FormFeed:
destination[written++] = (byte)'f';
break;
default:
destination[written++] = (byte)'u';
if (scalar < JsonConstants.UnicodePlane01StartValue)
{
bool result = Utf8Formatter.TryFormat(scalar, destination.Slice(written), out int bytesWritten, format: s_hexStandardFormat);
Debug.Assert(result);
Debug.Assert(bytesWritten == 4);
written += bytesWritten;
}
else
{
// Divide by 0x400 to shift right by 10 in order to find the surrogate pairs from the scalar
// High surrogate = ((scalar - 0x10000) / 0x400) + D800
// Low surrogate = ((scalar - 0x10000) % 0x400) + DC00
int quotient = Math.DivRem(scalar - JsonConstants.UnicodePlane01StartValue, JsonConstants.ShiftRightBy10, out int remainder);
int firstChar = quotient + JsonConstants.HighSurrogateStartValue;
int nextChar = remainder + JsonConstants.LowSurrogateStartValue;
bool result = Utf8Formatter.TryFormat(firstChar, destination.Slice(written), out int bytesWritten, format: s_hexStandardFormat);
Debug.Assert(result);
Debug.Assert(bytesWritten == 4);
written += bytesWritten;
destination[written++] = (byte)'\\';
destination[written++] = (byte)'u';
result = Utf8Formatter.TryFormat(nextChar, destination.Slice(written), out bytesWritten, format: s_hexStandardFormat);
Debug.Assert(result);
Debug.Assert(bytesWritten == 4);
written += bytesWritten;
}
break;
}
return(numBytesConsumed);
}
private static int EscapeNextBytes(ReadOnlySpan <byte> value, ref Span <byte> destination, ref int written)
{
SequenceValidity status = Utf8Utility.PeekFirstSequence(value, out int numBytesConsumed, out UnicodeScalar unicodeScalar);
if (status != SequenceValidity.WellFormed)
{
JsonThrowHelper.ThrowJsonWriterException("Invalid UTF-8 string.");
}
destination[written++] = (byte)'\\';
int scalar = unicodeScalar.Value;
switch (scalar)
{
case '\n':
destination[written++] = (byte)'n';
break;
case '\r':
destination[written++] = (byte)'r';
break;
case '\t':
destination[written++] = (byte)'t';
break;
case '\\':
destination[written++] = (byte)'\\';
break;
case '/':
destination[written++] = (byte)'/';
break;
case '\b':
destination[written++] = (byte)'b';
break;
case '\f':
destination[written++] = (byte)'f';
break;
default:
destination[written++] = (byte)'u';
if (scalar < 0x10000)
{
WriteHex(scalar, ref destination, ref written);
}
else
{
int quotient = DivMod(scalar - 0x10000, 0x400, out int remainder);
int firstChar = quotient + 0xD800;
int nextChar = remainder + 0xDC00;
WriteHex(firstChar, ref destination, ref written);
destination[written++] = (byte)'\\';
destination[written++] = (byte)'u';
WriteHex(nextChar, ref destination, ref written);
}
break;
}
return(numBytesConsumed);
}
