/**
* Copyright 2010 JBoss Inc
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.eclipse.webdav.internal.authentication;
/**
* A simple parser that is mainly used to parse HTTP header fields.
*/
public class Parser {
/**
* The string being parsed.
*/
public String s;
/**
* The index of the next character in s to be parsed.
*/
public int pos;
/**
* Creates a new parser on the given string.
*
* @param s the string to be parsed
*/
public Parser(String s) {
this.s = s;
}
/**
* Throws a <code>ParserException</code> if <code>pos</code> is out of
* range.
*/
public void checkPosition() throws ParserException {
if (pos < 0 || pos >= s.length())
throw new ParserException();
}
/**
* Skips the next character in s if it matches c, otherwise a
* <code>ParserException</code> is thrown.
*
* @param c
* @throws ParserException
*/
public void match(char c) throws ParserException {
checkPosition();
if (s.charAt(pos) != c)
throw new ParserException();
++pos;
}
/**
* Returns the next quoted string is s (quotes included). Throws a
* <code>ParserException</code> if the next substring in s is not a
* quoted string.
*
* @return the next quoted string in s (quotes included)
* @throws ParserException
*/
public String nextQuotedString() throws ParserException {
int start = pos;
match('"');
checkPosition();
while (s.charAt(pos) != '"') {
++pos;
checkPosition();
}
match('"');
return s.substring(start, pos);
}
/**
* Returns the next token in s. Throws a <code>ParserException</code> if
* the next substring in s is not a token.
*
* @return the next token in s
* @throws ParserException
*/
public String nextToken() throws ParserException {
int start = pos;
checkPosition();
boolean done = false;
while (!done && pos < s.length()) {
int c = s.charAt(pos);
if (c <= 31 //
|| c == 127 //
|| c == '(' //
|| c == ')' //
|| c == '<' //
|| c == '>' //
|| c == '@' //
|| c == ',' //
|| c == ';' //
|| c == ':' //
|| c == '\\' //
|| c == '"' //
|| c == '/' //
|| c == '[' //
|| c == ']' //
|| c == '?' //
|| c == '=' //
|| c == '{' //
|| c == '}' //
|| Character.isWhitespace((char) c)) {
done = true;
} else {
++pos;
}
}
if (start == pos) {
throw new ParserException();
}
return s.substring(start, pos);
}
/**
* Skips the next sequence of white space in s. An exception is not
* thrown if there is no matching white space.
*/
public void skipWhiteSpace() {
while (pos < s.length() && Character.isWhitespace(s.charAt(pos)))
++pos;
}
}