/* * Copyright 2001-2004 The Apache Software Foundation * * 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.apache.commons.fileupload;import java.util.HashMap;import java.util.Map;/** * 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> */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;    /**     * Whether names stored in the map should be converted to lower case.     */    private boolean lowerCaseNames = false;    /**     * Default ParameterParser constructor.     */    public ParameterParser() {        super();    }    /**     * Are there any characters left to parse?     *     * @return <tt>true</tt> if there are unparsed characters,     *         <tt>false</tt> otherwise.     */    private boolean hasChar() {        return this.pos < this.len;    }    /**     * A helper method to process the parsed token. This method removes     * leading and trailing blanks as well as enclosing quotation marks,     * when necessary.     *     * @param quoted <tt>true</tt> if quotation marks are expected,     *               <tt>false</tt> otherwise.     * @return the 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 quotation marks 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;    }    /**     * Tests if the given character is present in the array of characters.     *     * @param ch the character to test for presense in the array of characters     * @param charray the array of characters to test against     *     * @return <tt>true</tt> if the character is present in the array of     *   characters, <tt>false</tt> otherwise.     */    private boolean isOneOf(char ch, final char[] charray) {        boolean result = false;        for (int i = 0; i < charray.length; i++) {            if (ch == charray[i]) {                result = true;                break;            }        }        return result;    }    /**     * Parses out a token until any of the given terminators     * is encountered.     *     * @param terminators the array of terminating characters. Any of these     * characters when encountered signify the end of the token     *     * @return the token     */    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);    }    /**     * Parses out a token until any of the given terminators     * is encountered outside the quotation marks.     *     * @param terminators the array of terminating characters. Any of these     * characters when encountered outside the quotation marks signify the end     * of the token     *     * @return the token     */    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);    }    /**     * Returns <tt>true</tt> if parameter names are to be converted to lower     * case when name/value pairs are parsed.     *     * @return <tt>true</tt> if parameter names are to be     * converted to lower case when name/value pairs are parsed.     * Otherwise returns <tt>false</tt>     */    public boolean isLowerCaseNames() {        return this.lowerCaseNames;    }    /**     * Sets the flag if parameter names are to be converted to lower case when     * name/value pairs are parsed.     *     * @param b <tt>true</tt> if parameter names are to be     * converted to lower case when name/value pairs are parsed.     * <tt>false</tt> otherwise.     */    public void setLowerCaseNames(boolean b) {        this.lowerCaseNames = b;    }    /**     * Extracts a map of name/value pairs from the given string. Names are     * expected to be unique.     *     * @param str the string that contains a sequence of name/value pairs     * @param separator the name/value pairs separator     *     * @return a map of name/value pairs     */    public Map parse(final String str, char separator) {        if (str == null) {            return new HashMap();        }        return parse(str.toCharArray(), separator);    }    /**     * Extracts a map of name/value pairs from the given array of     * characters. Names are expected to be unique.     *     * @param chars the array of characters that contains a sequence of     * name/value pairs     * @param separator the name/value pairs separator     *     * @return a map of name/value pairs     */    public Map parse(final char[] chars, char separator) {        if (chars == null) {            return new HashMap();        }        return parse(chars, 0, chars.length, separator);    }    /**     * Extracts a map of name/value pairs from the given array of     * characters. Names are expected to be unique.     *     * @param chars the array of characters that contains a sequence of     * name/value pairs     * @param offset - the initial offset.     * @param length - the length.     * @param separator the name/value pairs separator     *     * @return a map of name/value pairs     */    public Map parse(        final char[] chars,        int offset,        int length,        char separator) {        if (chars == null) {            return new HashMap();        }        HashMap params = new HashMap();        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.length() > 0)) {                if (this.lowerCaseNames) {                    paramName = paramName.toLowerCase();                }                params.put(paramName, paramValue);            }        }        return params;    }}