/*
* $Header: /home/jerenkrantz/tmp/commons/commons-convert/cvs/home/cvs/jakarta-commons//httpclient/src/java/org/apache/commons/httpclient/util/ParameterParser.java,v 1.5 2004/05/13 04:01:22 mbecke Exp $
* $Revision: 480424 $
* $Date: 2006-11-29 06:56:49 +0100 (Wed, 29 Nov 2006) $
*
* ====================================================================
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*
*/
package org.apache.commons.httpclient.util;
import java.util.ArrayList;
import java.util.List;
import org.apache.commons.httpclient.NameValuePair;
/**
* A simple parser intended to parse sequences of name/value pairs.
* Parameter values are exptected to be enclosed in quotes if they
* contain unsafe characters, such as '=' characters or separators.
* Parameter values are optional and can be omitted.
*
* <p>
* <code>param1 = value; param2 = "anything goes; really"; param3</code>
* </p>
*
* @author <a href="mailto:oleg@ural.ru">Oleg Kalnichevski</a>
*
* @since 3.0
*/
public class ParameterParser {
/** String to be parsed */
private char[] chars = null;
/** Current position in the string */
private int pos = 0;
/** Maximum position in the string */
private int len = 0;
/** Start of a token */
private int i1 = 0;
/** End of a token */
private int i2 = 0;
/** Default ParameterParser constructor */
public ParameterParser() {
super();
}
/** Are there any characters left to parse? */
private boolean hasChar() {
return this.pos < this.len;
}
/** A helper method to process the parsed token. */
private String getToken(boolean quoted) {
// Trim leading white spaces
while ((i1 < i2) && (Character.isWhitespace(chars[i1]))) {
i1++;
}
// Trim trailing white spaces
while ((i2 > i1) && (Character.isWhitespace(chars[i2 - 1]))) {
i2--;
}
// Strip away quotes if necessary
if (quoted) {
if (((i2 - i1) >= 2)
&& (chars[i1] == '"')
&& (chars[i2 - 1] == '"')) {
i1++;
i2--;
}
}
String result = null;
if (i2 >= i1) {
result = new String(chars, i1, i2 - i1);
}
return result;
}
/** Is given character present in the array of characters? */
private boolean isOneOf(char ch, char[] charray) {
boolean result = false;
for (int i = 0; i < charray.length; i++) {
if (ch == charray[i]) {
result = true;
break;
}
}
return result;
}
/** Parse out a token until any of the given terminators
* is encountered. */
private String parseToken(final char[] terminators) {
char ch;
i1 = pos;
i2 = pos;
while (hasChar()) {
ch = chars[pos];
if (isOneOf(ch, terminators)) {
break;
}
i2++;
pos++;
}
return getToken(false);
}
/** Parse out a token until any of the given terminators
* is encountered. Special characters in quoted tokens
* are escaped. */
private String parseQuotedToken(final char[] terminators) {
char ch;
i1 = pos;
i2 = pos;
boolean quoted = false;
boolean charEscaped = false;
while (hasChar()) {
ch = chars[pos];
if (!quoted && isOneOf(ch, terminators)) {
break;
}
if (!charEscaped && ch == '"') {
quoted = !quoted;
}
charEscaped = (!charEscaped && ch == '\\');
i2++;
pos++;
}
return getToken(true);
}
/**
* Extracts a list of {@link NameValuePair}s from the given string.
*
* @param str the string that contains a sequence of name/value pairs
* @return a list of {@link NameValuePair}s
*
*/
public List parse(final String str, char separator) {
if (str == null) {
return new ArrayList();
}
return parse(str.toCharArray(), separator);
}
/**
* Extracts a list of {@link NameValuePair}s from the given array of
* characters.
*
* @param chars the array of characters that contains a sequence of
* name/value pairs
*
* @return a list of {@link NameValuePair}s
*/
public List parse(final char[] chars, char separator) {
if (chars == null) {
return new ArrayList();
}
return parse(chars, 0, chars.length, separator);
}
/**
* Extracts a list of {@link NameValuePair}s from the given array of
* characters.
*
* @param chars the array of characters that contains a sequence of
* name/value pairs
* @param offset - the initial offset.
* @param length - the length.
*
* @return a list of {@link NameValuePair}s
*/
public List parse(final char[] chars, int offset, int length, char separator) {
if (chars == null) {
return new ArrayList();
}
List params = new ArrayList();
this.chars = chars;
this.pos = offset;
this.len = length;
String paramName = null;
String paramValue = null;
while (hasChar()) {
paramName = parseToken(new char[] {'=', separator});
paramValue = null;
if (hasChar() && (chars[pos] == '=')) {
pos++; // skip '='
paramValue = parseQuotedToken(new char[] {separator});
}
if (hasChar() && (chars[pos] == separator)) {
pos++; // skip separator
}
if (paramName != null && !(paramName.equals("") && paramValue == null)) {
params.add(new NameValuePair(paramName, paramValue));
}
}
return params;
}
}