public override unsafe int GetByteCount(char *chars, int count, bool flush)
{
ArgumentNullException.ThrowIfNull(chars);
if (count < 0)
{
throw new ArgumentOutOfRangeException(nameof(count), SR.ArgumentOutOfRange_NeedNonNegNum);
}
bool excludeLastChar = count > 0 && !flush && char.IsHighSurrogate(chars[count - 1]);
if (excludeLastChar)
{
count--;
}
if (_charLeftOver == NULL_CHAR)
{
if (count <= 0)
{
return(0);
}
return(OSEncoding.WideCharToMultiByte(_encoding.CodePage, chars, count, null, 0));
}
// we have left over character
if (count == 0 && !excludeLastChar && !flush)
{
return(0);
}
return(ConvertWithLeftOverChar(chars, count, null, 0));
}
private unsafe int ConvertWithLeftOverChar(char *chars, int count, byte *bytes, int byteCount)
{
Debug.Assert(_charLeftOver != NULL_CHAR);
char *pTempBuffer = stackalloc char[2];
pTempBuffer[0] = _charLeftOver;
int index = 0;
if (count > 0 && char.IsLowSurrogate(chars[0]))
{
pTempBuffer[1] = chars[0];
index++;
}
int result = OSEncoding.WideCharToMultiByte(_encoding.CodePage, pTempBuffer, index + 1, bytes, byteCount);
if (count - index > 0)
{
result += OSEncoding.WideCharToMultiByte(
_encoding.CodePage, chars + index,
count - index,
bytes == null ? null : bytes + result,
bytes == null ? 0 : byteCount - result);
}
return(result);
}
private unsafe int ConvertWithLeftOverByte(byte *bytes, int count, char *chars, int charCount)
{
Debug.Assert(_leftOverLeadByte != 0);
byte *pTempBuffer = stackalloc byte[2];
pTempBuffer[0] = _leftOverLeadByte;
int index = 0;
if (count > 0)
{
pTempBuffer[1] = bytes[0];
index++;
}
int result = OSEncoding.MultiByteToWideChar(_encoding.CodePage, pTempBuffer, index + 1, chars, charCount);
if (count - index > 0)
{
result += OSEncoding.MultiByteToWideChar(
_encoding.CodePage, bytes + index,
count - index,
chars == null ? null : chars + result,
chars == null ? 0 : charCount - result);
}
return(result);
}
public unsafe override int GetCharCount(byte *bytes, int count, bool flush)
{
ArgumentNullException.ThrowIfNull(bytes);
if (count < 0)
{
throw new ArgumentOutOfRangeException(nameof(count), SR.ArgumentOutOfRange_NeedNonNegNum);
}
bool excludeLastByte = count > 0 && !flush && IsLastByteALeadByte(bytes, count);
if (excludeLastByte)
{
count--;
}
if (_leftOverLeadByte == 0)
{
if (count <= 0)
{
return(0);
}
return(OSEncoding.MultiByteToWideChar(_encoding.CodePage, bytes, count, null, 0));
}
if (count == 0 && !excludeLastByte && !flush)
{
return(0);
}
return(ConvertWithLeftOverByte(bytes, count, null, 0));
}
public unsafe override int GetChars(byte *bytes, int byteCount, char *chars, int charCount, bool flush)
{
if (chars == null || bytes == null)
{
throw new ArgumentNullException(chars == null ? nameof(chars) : nameof(bytes), SR.ArgumentNull_Array);
}
if (byteCount < 0 || charCount < 0)
{
throw new ArgumentOutOfRangeException(byteCount < 0 ? nameof(byteCount) : nameof(charCount), SR.ArgumentOutOfRange_NeedNonNegNum);
}
if (charCount == 0)
{
return(0);
}
byte lastByte = byteCount > 0 && !flush && IsLastByteALeadByte(bytes, byteCount) ? bytes[byteCount - 1] : (byte)0;
if (lastByte != 0)
{
byteCount--;
}
if (_leftOverLeadByte == 0)
{
if (byteCount <= 0)
{
_leftOverLeadByte = lastByte;
return(0);
}
int result = OSEncoding.MultiByteToWideChar(_encoding.CodePage, bytes, byteCount, chars, charCount);
_leftOverLeadByte = lastByte;
return(result);
}
// we have left over lead byte
if (byteCount == 0 && lastByte == 0 && !flush)
{
return(0);
}
int res = ConvertWithLeftOverByte(bytes, byteCount, chars, charCount);
_leftOverLeadByte = lastByte;
return(res);
}
public unsafe override int GetBytes(char *chars, int charCount, byte *bytes, int byteCount, bool flush)
{
if (chars == null || bytes == null)
{
throw new ArgumentNullException(chars == null ? nameof(chars) : nameof(bytes), SR.ArgumentNull_Array);
}
if (byteCount < 0 || charCount < 0)
{
throw new ArgumentOutOfRangeException(byteCount < 0 ? nameof(byteCount) : nameof(charCount), SR.ArgumentOutOfRange_NeedNonNegNum);
}
if (byteCount == 0)
{
return(0);
}
char lastChar = charCount > 0 && !flush && Char.IsHighSurrogate(chars[charCount - 1]) ? chars[charCount - 1] : NULL_CHAR;
if (lastChar != NULL_CHAR)
{
charCount--;
}
if (_charLeftOver == NULL_CHAR)
{
if (charCount <= 0)
{
_charLeftOver = lastChar;
return(0);
}
int result = OSEncoding.WideCharToMultiByte(_encoding.CodePage, chars, charCount, bytes, byteCount);
_charLeftOver = lastChar;
return(result);
}
// we have left over character
if (charCount == 0 && lastChar == NULL_CHAR && !flush)
{
return(0);
}
int res = ConvertWithLeftOverChar(chars, charCount, bytes, byteCount);
_charLeftOver = lastChar;
return(res);
}
