/*

 * Copyright (c) 1997, 2012, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package com.sun.activation.registries;

/**

 *      A tokenizer for strings in the form of "foo/bar; prop1=val1; ... ".

 *      Useful for parsing MIME content types.

 */

public class MailcapTokenizer {

    public static final int UNKNOWN_TOKEN = 0;

    public static final int START_TOKEN = 1;

    public static final int STRING_TOKEN = 2;

    public static final int EOI_TOKEN = 5;

    public static final int SLASH_TOKEN = '/';

    public static final int SEMICOLON_TOKEN = ';';

    public static final int EQUALS_TOKEN = '=';

    /**

     *  Constructor

     *

     *  @param  inputString the string to tokenize

     */

    public MailcapTokenizer(String inputString) {

        data = inputString;

        dataIndex = 0;

        dataLength = inputString.length();

        currentToken = START_TOKEN;

        currentTokenValue = "";

        isAutoquoting = false;

        autoquoteChar = ';';

    }

    /**

     *  Set whether auto-quoting is on or off.

     *

     *  Auto-quoting means that all characters after the first

     *  non-whitespace, non-control character up to the auto-quote

     *  terminator character or EOI (minus any whitespace immediatley

     *  preceeding it) is considered a token.

     *

     *  This is required for handling command strings in a mailcap entry.

     */

    public void setIsAutoquoting(boolean value) {

        isAutoquoting = value;

    }

    /**

     *  Retrieve current token.

     *

     *  @return    The current token value

     */

    public int getCurrentToken() {

        return currentToken;

    }

    /*

     *  Get a String that describes the given token.

     */

    public static String nameForToken(int token) {

        String name = "really unknown";

        switch(token) {

            case UNKNOWN_TOKEN:

                name = "unknown";

                break;

            case START_TOKEN:

                name = "start";

                break;

            case STRING_TOKEN:

                name = "string";

                break;

            case EOI_TOKEN:

                name = "EOI";

                break;

            case SLASH_TOKEN:

                name = "'/'";

                break;

            case SEMICOLON_TOKEN:

                name = "';'";

                break;

            case EQUALS_TOKEN:

                name = "'='";

                break;

        }

        return name;

    }

    /*

     *  Retrieve current token value.

     *

     *  @return    A String containing the current token value

     */

    public String getCurrentTokenValue() {

        return currentTokenValue;

    }

    /*

     *  Process the next token.

     *

     *  @return    the next token

     */

    public int nextToken() {

        if (dataIndex < dataLength) {

            //  skip white space

            while ((dataIndex < dataLength) &&

                    (isWhiteSpaceChar(data.charAt(dataIndex)))) {

                ++dataIndex;

            }

            if (dataIndex < dataLength) {

                //  examine the current character and see what kind of token we have

                char c = data.charAt(dataIndex);

                if (isAutoquoting) {

                    if (c == ';' || c == '=') {

                        currentToken = c;

                        currentTokenValue = new Character(c).toString();

                        ++dataIndex;

                    } else {

                        processAutoquoteToken();

                    }

                } else {

                    if (isStringTokenChar(c)) {

                        processStringToken();

                    } else if ((c == '/') || (c == ';') || (c == '=')) {

                        currentToken = c;

                        currentTokenValue = new Character(c).toString();

                        ++dataIndex;

                    } else {

                        currentToken = UNKNOWN_TOKEN;

                        currentTokenValue = new Character(c).toString();

                        ++dataIndex;

                    }

                }

            } else {

                currentToken = EOI_TOKEN;

                currentTokenValue = null;

            }

        } else {

            currentToken = EOI_TOKEN;

            currentTokenValue = null;

        }

        return currentToken;

    }

    private void processStringToken() {

        //  capture the initial index

        int initialIndex = dataIndex;

        //  skip to 1st non string token character

        while ((dataIndex < dataLength) &&

                isStringTokenChar(data.charAt(dataIndex))) {

            ++dataIndex;

        }

        currentToken = STRING_TOKEN;

        currentTokenValue = data.substring(initialIndex, dataIndex);

    }

    private void processAutoquoteToken() {

        //  capture the initial index

        int initialIndex = dataIndex;

        //  now skip to the 1st non-escaped autoquote termination character

        //  XXX - doesn't actually consider escaping

        boolean foundTerminator = false;

        while ((dataIndex < dataLength) && !foundTerminator) {

            char c = data.charAt(dataIndex);

            if (c != autoquoteChar) {

                ++dataIndex;

            } else {

                foundTerminator = true;

            }

        }

        currentToken = STRING_TOKEN;

        currentTokenValue =

            fixEscapeSequences(data.substring(initialIndex, dataIndex));

    }

    private static boolean isSpecialChar(char c) {

        boolean lAnswer = false;

        switch(c) {

            case '(':

            case ')':

            case '<':

            case '>':

            case '@':

            case ',':

            case ';':

            case ':':

            case '\\':

            case '"':

            case '/':

            case '[':

            case ']':

            case '?':

            case '=':

                lAnswer = true;

                break;

        }

        return lAnswer;

    }

    private static boolean isControlChar(char c) {

        return Character.isISOControl(c);

    }

    private static boolean isWhiteSpaceChar(char c) {

        return Character.isWhitespace(c);

    }

    private static boolean isStringTokenChar(char c) {

        return !isSpecialChar(c) && !isControlChar(c) && !isWhiteSpaceChar(c);

    }

    private static String fixEscapeSequences(String inputString) {

        int inputLength = inputString.length();

        StringBuffer buffer = new StringBuffer();

        buffer.ensureCapacity(inputLength);

        for (int i = 0; i < inputLength; ++i) {

            char currentChar = inputString.charAt(i);

            if (currentChar != '\\') {

                buffer.append(currentChar);

            } else {

                if (i < inputLength - 1) {

                    char nextChar = inputString.charAt(i + 1);

                    buffer.append(nextChar);

                    //  force a skip over the next character too

                    ++i;

                } else {

                    buffer.append(currentChar);

                }

            }

        }

        return buffer.toString();

    }

    private String  data;

    private int     dataIndex;

    private int     dataLength;

    private int     currentToken;

    private String  currentTokenValue;

    private boolean isAutoquoting;

    private char    autoquoteChar;

    /*

    public static void main(String[] args) {

        for (int i = 0; i < args.length; ++i) {

            MailcapTokenizer tokenizer = new MailcapTokenizer(args[i]);

            System.out.println("Original: |" + args[i] + "|");

            int currentToken = tokenizer.nextToken();

            while (currentToken != EOI_TOKEN) {

                switch(currentToken) {

                    case UNKNOWN_TOKEN:

                        System.out.println("  Unknown Token:           |" + tokenizer.getCurrentTokenValue() + "|");

                        break;

                    case START_TOKEN:

                        System.out.println("  Start Token:             |" + tokenizer.getCurrentTokenValue() + "|");

                        break;

                    case STRING_TOKEN:

                        System.out.println("  String Token:            |" + tokenizer.getCurrentTokenValue() + "|");

                        break;

                    case EOI_TOKEN:

                        System.out.println("  EOI Token:               |" + tokenizer.getCurrentTokenValue() + "|");

                        break;

                    case SLASH_TOKEN:

                        System.out.println("  Slash Token:             |" + tokenizer.getCurrentTokenValue() + "|");

                        break;

                    case SEMICOLON_TOKEN:

                        System.out.println("  Semicolon Token:         |" + tokenizer.getCurrentTokenValue() + "|");

                        break;

                    case EQUALS_TOKEN:

                        System.out.println("  Equals Token:            |" + tokenizer.getCurrentTokenValue() + "|");

                        break;

                    default:

                        System.out.println("  Really Unknown Token:    |" + tokenizer.getCurrentTokenValue() + "|");

                        break;

                }

                currentToken = tokenizer.nextToken();

            }

            System.out.println("");

        }

    }

    */

}