| static private IsControlChar ( char c ) : bool | ||
| c | char | a char |
| return | bool | |
/// <seealso cref= Reader#read(char[], int, int) </seealso>
public override int Read(char[] cbuf, int off, int len)
{
int readAhead = 0;
int read = 0;
int pos = off;
char[] readAheadBuffer = new char[BUFFER_SIZE];
bool available = true;
while (available && read < len)
{
available = base.Read(readAheadBuffer, readAhead, 1) == 1;
if (available)
{
char c = ProcessChar(readAheadBuffer[readAhead]);
if (_state == STATE_START)
{
// replace control chars with space
if (Utils.IsControlChar(c))
{
c = ' ';
}
cbuf[pos++] = c;
readAhead = 0;
read++;
}
else if (_state == STATE_ERROR)
{
Unread(readAheadBuffer, 0, readAhead + 1);
readAhead = 0;
}
else
{
readAhead++;
}
}
else if (readAhead > 0)
{
// handles case when file ends within excaped sequence
Unread(readAheadBuffer, 0, readAhead);
_state = STATE_ERROR;
readAhead = 0;
available = true;
}
}
return(read > 0 || available ? read : -1);
}
/// <summary>
/// Processes numeric escaped chars to find out if they are a control character. </summary>
/// <param name="ch"> a char </param>
/// <returns> Returns the char directly or as replacement for the escaped sequence. </returns>
private char ProcessChar(char ch)
{
switch (_state)
{
case STATE_START:
if (ch == '&')
{
_state = STATE_AMP;
}
return(ch);
case STATE_AMP:
_state = ch == '#' ? STATE_HASH : STATE_ERROR;
return(ch);
case STATE_HASH:
if (ch == 'x')
{
_control = 0;
_digits = 0;
_state = STATE_HEX;
}
else if ('0' <= ch && ch <= '9')
{
_control = Convert.ToInt32(ch.ToString(CultureInfo.InvariantCulture), 10);
_digits = 1;
_state = STATE_DIG1;
}
else
{
_state = STATE_ERROR;
}
return(ch);
case STATE_DIG1:
if ('0' <= ch && ch <= '9')
{
_control = _control * 10 + Convert.ToInt32(ch.ToString(CultureInfo.InvariantCulture), 10);
_digits++;
_state = _digits <= 5 ? STATE_DIG1 : STATE_ERROR;
}
else if (ch == ';' && Utils.IsControlChar((char)_control))
{
_state = STATE_START;
return((char)_control);
}
else
{
_state = STATE_ERROR;
}
return(ch);
case STATE_HEX:
if (('0' <= ch && ch <= '9') || ('a' <= ch && ch <= 'f') || ('A' <= ch && ch <= 'F'))
{
_control = _control * 16 + Convert.ToInt32(ch.ToString(CultureInfo.InvariantCulture), 16);
_digits++;
_state = _digits <= 4 ? STATE_HEX : STATE_ERROR;
}
else if (ch == ';' && Utils.IsControlChar((char)_control))
{
_state = STATE_START;
return((char)_control);
}
else
{
_state = STATE_ERROR;
}
return(ch);
case STATE_ERROR:
_state = STATE_START;
return(ch);
default:
// not reachable
return(ch);
}
}
