// Fast-Path implementation
internal static int WriteUtf8(AbstractByteBuffer buffer, int writerIndex, string value, int len)
{
int oldWriterIndex = writerIndex;
// We can use the _set methods as these not need to do any index checks and reference checks.
// This is possible as we called ensureWritable(...) before.
for (int i = 0; i < len; i++)
{
char c = value[i];
if (c < 0x80)
{
buffer._SetByte(writerIndex++, (byte)c);
}
else if (c < 0x800)
{
buffer._SetByte(writerIndex++, (byte)(0xc0 | (c >> 6)));
buffer._SetByte(writerIndex++, (byte)(0x80 | (c & 0x3f)));
}
else if (char.IsSurrogate(c))
{
if (!char.IsHighSurrogate(c))
{
buffer._SetByte(writerIndex++, WriteUtfUnknown);
continue;
}
char c2;
try
{
// Surrogate Pair consumes 2 characters. Optimistically try to get the next character to avoid
// duplicate bounds checking with charAt. If an IndexOutOfBoundsException is thrown we will
// re-throw a more informative exception describing the problem.
c2 = value[++i];
}
catch (IndexOutOfRangeException)
{
buffer._SetByte(writerIndex++, WriteUtfUnknown);
break;
}
if (!char.IsLowSurrogate(c2))
{
buffer._SetByte(writerIndex++, WriteUtfUnknown);
buffer._SetByte(writerIndex++, char.IsHighSurrogate(c2) ? WriteUtfUnknown : c2);
continue;
}
int codePoint = CharUtil.ToCodePoint(c, c2);
// See http://www.unicode.org/versions/Unicode7.0.0/ch03.pdf#G2630.
buffer._SetByte(writerIndex++, (byte)(0xf0 | (codePoint >> 18)));
buffer._SetByte(writerIndex++, (byte)(0x80 | ((codePoint >> 12) & 0x3f)));
buffer._SetByte(writerIndex++, (byte)(0x80 | ((codePoint >> 6) & 0x3f)));
buffer._SetByte(writerIndex++, (byte)(0x80 | (codePoint & 0x3f)));
}
else
{
buffer._SetByte(writerIndex++, (byte)(0xe0 | (c >> 12)));
buffer._SetByte(writerIndex++, (byte)(0x80 | ((c >> 6) & 0x3f)));
buffer._SetByte(writerIndex++, (byte)(0x80 | (c & 0x3f)));
}
}
return(writerIndex - oldWriterIndex);
}