/**
* Read the next token from 'this.line' and append it to 'this.buf'. Tokens are separated by
* Pattern_White_Space. Tokens may also be delimited by double or single quotes. The closing quote
* must match the opening quote. If a '#' is encountered, the rest of the line is ignored, unless
* it is backslash-escaped or within quotes.
*
* @param position the offset into the string
* @return offset to the next character to read from line, or if the end of the line is reached
* without scanning a valid token, -1
*/
private int nextToken(int position) {
position = PatternProps.skipWhiteSpace(line, position);
if (position == line.length()) {
return -1;
}
int startpos = position;
char c = line.charAt(position++);
char quote = 0;
switch (c) {
case '"':
case '\'':
quote = c;
break;
case '#':
return -1;
default:
buf.append(c);
break;
}
int[] posref = null;
while (position < line.length()) {
c = line.charAt(position); // 16-bit ok
if (c == '\\') {
if (posref == null) {
posref = new int[1];
}
posref[0] = position + 1;
int c32 = Utility.unescapeAt(line, posref);
if (c32 < 0) {
throw new RuntimeException(
"Invalid escape at " + reader.describePosition() + ':' + position);
}
UTF16.append(buf, c32);
position = posref[0];
} else if ((quote != 0 && c == quote) || (quote == 0 && PatternProps.isWhiteSpace(c))) {
return ++position;
} else if (quote == 0 && c == '#') {
return position; // do NOT increment
} else {
buf.append(c);
++position;
}
}
if (quote != 0) {
throw new RuntimeException(
"Unterminated quote at " + reader.describePosition() + ':' + startpos);
}
return position;
}
/**
* Return a string description of the position of the last line returned by readLine() or
* readLineSkippingComments().
*/
public String describePosition() {
return reader.describePosition() + ':' + (lastpos + 1);
}