private static bool TryFindEncodedCodePointBytesCountGoingBackwards(ReadOnlySpan <byte> buffer, out int encodedBytes)
{
encodedBytes = 1;
ReadOnlySpan <byte> it = buffer;
// TODO: Should we have something like: Span<byte>.(Slice from the back)
for (; encodedBytes <= UnicodeConstants.Utf8MaxCodeUnitsPerCodePoint; encodedBytes++, it = it.Slice(0, it.Length - 1))
{
if (it.Length == 0)
{
encodedBytes = default(int);
return(false);
}
// TODO: Should we have Span<byte>.Last?
if (Utf8CodeUnit.IsFirstCodeUnitInEncodedCodePoint(it[it.Length - 1]))
{
// output: encodedBytes
return(true);
}
}
// Invalid unicode character or stream prematurely ended (which is still invalid character in that stream)
encodedBytes = default(int);
return(false);
}
public bool EndsWith(Utf8CodeUnit codeUnit)
{
if (Length == 0)
{
return(false);
}
return(this[Length - 1] == codeUnit);
}
public bool StartsWith(Utf8CodeUnit codeUnit)
{
if (Length == 0)
{
return(false);
}
return(this[0] == codeUnit);
}
public static bool TryCreateFrom(char value, out Utf8CodeUnit codeUnit)
{
if (IsAscii(value))
{
codeUnit = new Utf8CodeUnit(unchecked ((byte)value));
return(true);
}
codeUnit = default(Utf8CodeUnit);
return(false);
}
public static bool TryCreateFrom(char value, out Utf8CodeUnit codeUnit)
{
if (IsAscii(value))
{
codeUnit = new Utf8CodeUnit(unchecked((byte)value));
return true;
}
codeUnit = default(Utf8CodeUnit);
return false;
}
public bool TrySubstringTo(Utf8CodeUnit codeUnit, out Utf8String result)
{
int idx = IndexOf(codeUnit);
if (idx == StringNotFound)
{
result = default(Utf8String);
return(false);
}
result = Substring(0, idx);
return(true);
}
// TODO: Should this be public?
public int IndexOf(Utf8CodeUnit codeUnit)
{
// TODO: _buffer.IndexOf(codeUnit.Value); when Span has it
for (int i = 0; i < Length; i++)
{
if (codeUnit == this[i])
{
return(i);
}
}
return(StringNotFound);
}
private Utf8String ReadToByte(Utf8CodeUnit codeUnit, bool includeCodeUnit)
{
SkipAll();
var count = 1;
while (_str[_index] != codeUnit)
{
count++;
_index++;
}
if (!includeCodeUnit)
{
count--;
_index--;
}
var utf8Bytes = new byte[count];
for (var i = 0; i < count; i++)
{
utf8Bytes[i] = (byte) _str[_index - count + i + 1];
}
_index++;
if (!includeCodeUnit)
{
_index++;
}
return new Utf8String(utf8Bytes);
}
