/** * Moves a position forward. On entry, <code>pos</code> gives * the position of the byte at index <code>off</code> in * <code>buf</code>. On exit, it <code>pos</code> will give * the position of the byte at index <code>end</code>, which * must be greater than or equal to <code>off</code>. The * bytes between <code>off</code> and <code>end</code> must * encode one or more complete characters. A carriage return * followed by a line feed will be treated as a single line * delimiter provided that they are given to * <code>movePosition</code> together. */ protected abstract void movePosition(byte[] buf, int off, int end, Position pos);
/// <summary>
///
/// </summary>
/// <param name="buf"></param>
/// <param name="off"></param>
/// <param name="end"></param>
/// <param name="pos"></param>
protected override void movePosition(byte[] buf, int off, int end, Position pos)
{
/* Maintain the invariant: off - colDiff == colNumber. */
int colDiff = off - pos.ColumnNumber;
int lineNumber = pos.LineNumber;
while (off != end)
{
byte b = buf[off];
if (b >= 0)
{
++off;
switch (b)
{
case (byte)'\n':
lineNumber += 1;
colDiff = off;
break;
case (byte)'\r':
lineNumber += 1;
if (off != end && buf[off] == '\n')
off++;
colDiff = off;
break;
}
}
else
{
switch (utf8TypeTable[b & 0xFF])
{
default:
off += 1;
break;
case BT_LEAD2:
off += 2;
colDiff++;
break;
case BT_LEAD3:
off += 3;
colDiff += 2;
break;
case BT_LEAD4:
off += 4;
colDiff += 3;
break;
}
}
}
pos.ColumnNumber = off - colDiff;
pos.LineNumber = lineNumber;
}