/*
 * Copyright (c) 2000, 2003, 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 javax.print;

import java.io.Serializable;

import java.util.AbstractMap;
import java.util.AbstractSet;
import java.util.Iterator;
import java.util.Map;
import java.util.NoSuchElementException;
import java.util.Set;
import java.util.Vector;

Class MimeType encapsulates a Multipurpose Internet Mail Extensions (MIME)
media type as defined in RFC
2045 and RFC 2046. A MIME type object is part of a DocFlavor object and specifies the format of the print data. 
 Class MimeType is similar to the like-named class in package java.awt.datatransfer. Class java.awt.datatransfer.MimeType is not used in the Jini Print Service API for two reasons: 


Since not all Java profiles include the AWT, the Jini Print Service should
not depend on an AWT class.


The implementation of class java.awt.datatransfer.MimeType does not
guarantee
that equivalent MIME types will have the same serialized representation.
Thus, since the Jini Lookup Service (JLUS) matches service attributes based
on equality of serialized representations, JLUS searches involving MIME
types encapsulated in class java.awt.datatransfer.MimeType may incorrectly
fail to match.


Class MimeType's serialized representation is based on the following
canonical form of a MIME type string. Thus, two MIME types that are not
identical but that are equivalent (that have the same canonical form) will
be considered equal by the JLUS's matching algorithm.

 The media type, media subtype, and parameters are retained, but all
     comments and whitespace characters are discarded.
 The media type, media subtype, and parameter names are converted to
     lowercase.
 The parameter values retain their original case, except a charset
     parameter value for a text media type is converted to lowercase.
 Quote characters surrounding parameter values are removed.
 Quoting backslash characters inside parameter values are removed.
 The parameters are arranged in ascending order of parameter name.


Author:
 Alan Kaminsky/**
 * Class MimeType encapsulates a Multipurpose Internet Mail Extensions (MIME)
 * media type as defined in <A HREF="http://www.ietf.org/rfc/rfc2045.txt">RFC
 * 2045</A> and <A HREF="http://www.ietf.org/rfc/rfc2046.txt">RFC 2046</A>. A
 * MIME type object is part of a {@link DocFlavor DocFlavor} object and
 * specifies the format of the print data.
 * <P>
 * Class MimeType is similar to the like-named
 * class in package {@link java.awt.datatransfer java.awt.datatransfer}. Class
 * java.awt.datatransfer.MimeType is not used in the Jini Print Service API
 * for two reasons:
 * <OL TYPE=1>
 * <LI>
 * Since not all Java profiles include the AWT, the Jini Print Service should
 * not depend on an AWT class.
 * <P>
 * <LI>
 * The implementation of class java.awt.datatransfer.MimeType does not
 * guarantee
 * that equivalent MIME types will have the same serialized representation.
 * Thus, since the Jini Lookup Service (JLUS) matches service attributes based
 * on equality of serialized representations, JLUS searches involving MIME
 * types encapsulated in class java.awt.datatransfer.MimeType may incorrectly
 * fail to match.
 * </OL>
 * <P>
 * Class MimeType's serialized representation is based on the following
 * canonical form of a MIME type string. Thus, two MIME types that are not
 * identical but that are equivalent (that have the same canonical form) will
 * be considered equal by the JLUS's matching algorithm.
 * <UL>
 * <LI> The media type, media subtype, and parameters are retained, but all
 *      comments and whitespace characters are discarded.
 * <LI> The media type, media subtype, and parameter names are converted to
 *      lowercase.
 * <LI> The parameter values retain their original case, except a charset
 *      parameter value for a text media type is converted to lowercase.
 * <LI> Quote characters surrounding parameter values are removed.
 * <LI> Quoting backslash characters inside parameter values are removed.
 * <LI> The parameters are arranged in ascending order of parameter name.
 * </UL>
 * <P>
 *
 * @author  Alan Kaminsky
 */
class MimeType implements Serializable, Cloneable {

    private static final long serialVersionUID = -2785720609362367683L;

    
Array of strings that hold pieces of this MIME type's canonical form.
If the MIME type has n parameters, n >= 0, then the
strings in the array are:

Index 0 -- Media type.

Index 1 -- Media subtype.

Index 2i+2 -- Name of parameter i,
i=0,1,...,n-1.

Index 2i+3 -- Value of parameter i,
i=0,1,...,n-1.

Parameters are arranged in ascending order of parameter name.
@serial
/**
     * Array of strings that hold pieces of this MIME type's canonical form.
     * If the MIME type has <I>n</I> parameters, <I>n</I> &gt;= 0, then the
     * strings in the array are:
     * <BR>Index 0 -- Media type.
     * <BR>Index 1 -- Media subtype.
     * <BR>Index 2<I>i</I>+2 -- Name of parameter <I>i</I>,
     * <I>i</I>=0,1,...,<I>n</I>-1.
     * <BR>Index 2<I>i</I>+3 -- Value of parameter <I>i</I>,
     * <I>i</I>=0,1,...,<I>n</I>-1.
     * <BR>Parameters are arranged in ascending order of parameter name.
     * @serial
     */
    private String[] myPieces;

    
String value for this MIME type. Computed when needed and cached.
/**
     * String value for this MIME type. Computed when needed and cached.
     */
    private transient String myStringValue = null;

    
Parameter map entry set. Computed when needed and cached.
/**
     * Parameter map entry set. Computed when needed and cached.
     */
    private transient ParameterMapEntrySet myEntrySet = null;

    
Parameter map. Computed when needed and cached.
/**
     * Parameter map. Computed when needed and cached.
     */
    private transient ParameterMap myParameterMap = null;

    
Parameter map entry.
/**
     * Parameter map entry.
     */
    private class ParameterMapEntry implements Map.Entry {
        private int myIndex;
        public ParameterMapEntry(int theIndex) {
            myIndex = theIndex;
        }
        public Object getKey(){
            return myPieces[myIndex];
        }
        public Object getValue(){
            return myPieces[myIndex+1];
        }
        public Object setValue (Object value) {
            throw new UnsupportedOperationException();
        }
        public boolean equals(Object o) {
            return (o != null &&
                    o instanceof Map.Entry &&
                    getKey().equals (((Map.Entry) o).getKey()) &&
                    getValue().equals(((Map.Entry) o).getValue()));
        }
        public int hashCode() {
            return getKey().hashCode() ^ getValue().hashCode();
        }
    }

    
Parameter map entry set iterator.
/**
     * Parameter map entry set iterator.
     */
    private class ParameterMapEntrySetIterator implements Iterator {
        private int myIndex = 2;
        public boolean hasNext() {
            return myIndex < myPieces.length;
        }
        public Object next() {
            if (hasNext()) {
                ParameterMapEntry result = new ParameterMapEntry (myIndex);
                myIndex += 2;
                return result;
            } else {
                throw new NoSuchElementException();
            }
        }
        public void remove() {
            throw new UnsupportedOperationException();
        }
    }

    
Parameter map entry set.
/**
     * Parameter map entry set.
     */
    private class ParameterMapEntrySet extends AbstractSet {
        public Iterator iterator() {
            return new ParameterMapEntrySetIterator();
        }
        public int size() {
            return (myPieces.length - 2) / 2;
        }
    }

    
Parameter map.
/**
     * Parameter map.
     */
    private class ParameterMap extends AbstractMap {
        public Set entrySet() {
            if (myEntrySet == null) {
                myEntrySet = new ParameterMapEntrySet();
            }
            return myEntrySet;
        }
    }

    
Construct a new MIME type object from the given string. The given
string is converted into canonical form and stored internally.
Params:
s –  MIME media type string.
Throws:
NullPointerException – 
    (unchecked exception) Thrown if s is null.
IllegalArgumentException – 
    (unchecked exception) Thrown if s does not obey the
    syntax for a MIME media type string./**
     * Construct a new MIME type object from the given string. The given
     * string is converted into canonical form and stored internally.
     *
     * @param  s  MIME media type string.
     *
     * @exception  NullPointerException
     *     (unchecked exception) Thrown if <CODE>s</CODE> is null.
     * @exception  IllegalArgumentException
     *     (unchecked exception) Thrown if <CODE>s</CODE> does not obey the
     *     syntax for a MIME media type string.
     */
    public MimeType(String s) {
        parse (s);
    }

    
Returns this MIME type object's MIME type string based on the canonical
form. Each parameter value is enclosed in quotes.
/**
     * Returns this MIME type object's MIME type string based on the canonical
     * form. Each parameter value is enclosed in quotes.
     */
    public String getMimeType() {
        return getStringValue();
    }

    
Returns this MIME type object's media type.
/**
     * Returns this MIME type object's media type.
     */
    public String getMediaType() {
        return myPieces[0];
    }

    
Returns this MIME type object's media subtype.
/**
     * Returns this MIME type object's media subtype.
     */
    public String getMediaSubtype() {
        return myPieces[1];
    }

    
Returns an unmodifiable map view of the parameters in this MIME type
object. Each entry in the parameter map view consists of a parameter
name String (key) mapping to a parameter value String. If this MIME
type object has no parameters, an empty map is returned.
Returns:
 Parameter map for this MIME type object./**
     * Returns an unmodifiable map view of the parameters in this MIME type
     * object. Each entry in the parameter map view consists of a parameter
     * name String (key) mapping to a parameter value String. If this MIME
     * type object has no parameters, an empty map is returned.
     *
     * @return  Parameter map for this MIME type object.
     */
    public Map getParameterMap() {
        if (myParameterMap == null) {
            myParameterMap = new ParameterMap();
        }
        return myParameterMap;
    }

    
Converts this MIME type object to a string.
Returns:
 MIME type string based on the canonical form. Each parameter
         value is enclosed in quotes./**
     * Converts this MIME type object to a string.
     *
     * @return  MIME type string based on the canonical form. Each parameter
     *          value is enclosed in quotes.
     */
    public String toString() {
        return getStringValue();
    }

    
Returns a hash code for this MIME type object.
/**
     * Returns a hash code for this MIME type object.
     */
    public int hashCode() {
        return getStringValue().hashCode();
    }

    
Determine if this MIME type object is equal to the given object. The two
are equal if the given object is not null, is an instance of class
net.jini.print.data.MimeType, and has the same canonical form as this
MIME type object (that is, has the same type, subtype, and parameters).
Thus, if two MIME type objects are the same except for comments, they are
considered equal. However, "text/plain" and "text/plain;
charset=us-ascii" are not considered equal, even though they represent
the same media type (because the default character set for plain text is
US-ASCII).
Params:
obj –  Object to test.
Returns:
 True if this MIME type object equals obj, false
         otherwise./**
     * Determine if this MIME type object is equal to the given object. The two
     * are equal if the given object is not null, is an instance of class
     * net.jini.print.data.MimeType, and has the same canonical form as this
     * MIME type object (that is, has the same type, subtype, and parameters).
     * Thus, if two MIME type objects are the same except for comments, they are
     * considered equal. However, "text/plain" and "text/plain;
     * charset=us-ascii" are not considered equal, even though they represent
     * the same media type (because the default character set for plain text is
     * US-ASCII).
     *
     * @param  obj  Object to test.
     *
     * @return  True if this MIME type object equals <CODE>obj</CODE>, false
     *          otherwise.
     */
    public boolean equals (Object obj) {
        return(obj != null &&
               obj instanceof MimeType &&
               getStringValue().equals(((MimeType) obj).getStringValue()));
    }

    
Returns this MIME type's string value in canonical form.
/**
     * Returns this MIME type's string value in canonical form.
     */
    private String getStringValue() {
        if (myStringValue == null) {
            StringBuffer result = new StringBuffer();
            result.append (myPieces[0]);
            result.append ('/');
            result.append (myPieces[1]);
            int n = myPieces.length;
            for (int i = 2; i < n; i += 2) {
                result.append(';');
                result.append(' ');
                result.append(myPieces[i]);
                result.append('=');
                result.append(addQuotes (myPieces[i+1]));
            }
            myStringValue = result.toString();
        }
        return myStringValue;
    }

// Hidden classes, constants, and operations for parsing a MIME media type
// string.

    // Lexeme types.
    private static final int TOKEN_LEXEME         = 0;
    private static final int QUOTED_STRING_LEXEME = 1;
    private static final int TSPECIAL_LEXEME      = 2;
    private static final int EOF_LEXEME           = 3;
    private static final int ILLEGAL_LEXEME       = 4;

    // Class for a lexical analyzer.
    private static class LexicalAnalyzer {
        protected String mySource;
        protected int mySourceLength;
        protected int myCurrentIndex;
        protected int myLexemeType;
        protected int myLexemeBeginIndex;
        protected int myLexemeEndIndex;

        public LexicalAnalyzer(String theSource) {
            mySource = theSource;
            mySourceLength = theSource.length();
            myCurrentIndex = 0;
            nextLexeme();
        }

        public int getLexemeType() {
            return myLexemeType;
        }

        public String getLexeme() {
            return(myLexemeBeginIndex >= mySourceLength ?
                   null :
                   mySource.substring(myLexemeBeginIndex, myLexemeEndIndex));
        }

        public char getLexemeFirstCharacter() {
            return(myLexemeBeginIndex >= mySourceLength ?
                   '\u0000' :
                   mySource.charAt(myLexemeBeginIndex));
        }

        public void nextLexeme() {
            int state = 0;
            int commentLevel = 0;
            char c;
            while (state >= 0) {
                switch (state) {
                    // Looking for a token, quoted string, or tspecial
                case 0:
                    if (myCurrentIndex >= mySourceLength) {
                        myLexemeType = EOF_LEXEME;
                        myLexemeBeginIndex = mySourceLength;
                        myLexemeEndIndex = mySourceLength;
                        state = -1;
                    } else if (Character.isWhitespace
                               (c = mySource.charAt (myCurrentIndex ++))) {
                        state = 0;
                    } else if (c == '\"') {
                        myLexemeType = QUOTED_STRING_LEXEME;
                        myLexemeBeginIndex = myCurrentIndex;
                        state = 1;
                    } else if (c == '(') {
                        ++ commentLevel;
                        state = 3;
                    } else if (c == '/'  || c == ';' || c == '=' ||
                               c == ')'  || c == '<' || c == '>' ||
                               c == '@'  || c == ',' || c == ':' ||
                               c == '\\' || c == '[' || c == ']' ||
                               c == '?') {
                        myLexemeType = TSPECIAL_LEXEME;
                        myLexemeBeginIndex = myCurrentIndex - 1;
                        myLexemeEndIndex = myCurrentIndex;
                        state = -1;
                    } else {
                        myLexemeType = TOKEN_LEXEME;
                        myLexemeBeginIndex = myCurrentIndex - 1;
                        state = 5;
                    }
                    break;
                    // In a quoted string
                case 1:
                    if (myCurrentIndex >= mySourceLength) {
                        myLexemeType = ILLEGAL_LEXEME;
                        myLexemeBeginIndex = mySourceLength;
                        myLexemeEndIndex = mySourceLength;
                        state = -1;
                    } else if ((c = mySource.charAt (myCurrentIndex ++)) == '\"') {
                        myLexemeEndIndex = myCurrentIndex - 1;
                        state = -1;
                    } else if (c == '\\') {
                        state = 2;
                    } else {
                        state = 1;
                    }
                    break;
                    // In a quoted string, backslash seen
                case 2:
                    if (myCurrentIndex >= mySourceLength) {
                        myLexemeType = ILLEGAL_LEXEME;
                        myLexemeBeginIndex = mySourceLength;
                        myLexemeEndIndex = mySourceLength;
                        state = -1;
                    } else {
                        ++ myCurrentIndex;
                        state = 1;
                    } break;
                    // In a comment
                case 3: if (myCurrentIndex >= mySourceLength) {
                    myLexemeType = ILLEGAL_LEXEME;
                    myLexemeBeginIndex = mySourceLength;
                    myLexemeEndIndex = mySourceLength;
                    state = -1;
                } else if ((c = mySource.charAt (myCurrentIndex ++)) == '(') {
                    ++ commentLevel;
                    state = 3;
                } else if (c == ')') {
                    -- commentLevel;
                    state = commentLevel == 0 ? 0 : 3;
                } else if (c == '\\') {
                    state = 4;
                } else { state = 3;
                }
                break;
                // In a comment, backslash seen
                case 4:
                    if (myCurrentIndex >= mySourceLength) {
                        myLexemeType = ILLEGAL_LEXEME;
                        myLexemeBeginIndex = mySourceLength;
                        myLexemeEndIndex = mySourceLength;
                        state = -1;
                    } else {
                        ++ myCurrentIndex;
                        state = 3;
                    }
                    break;
                    // In a token
                case 5:
                    if (myCurrentIndex >= mySourceLength) {
                        myLexemeEndIndex = myCurrentIndex;
                        state = -1;
                    } else if (Character.isWhitespace
                               (c = mySource.charAt (myCurrentIndex ++))) {
                        myLexemeEndIndex = myCurrentIndex - 1;
                        state = -1;
                    } else if (c == '\"' || c == '(' || c == '/' ||
                               c == ';'  || c == '=' || c == ')' ||
                               c == '<' || c == '>'  || c == '@' ||
                               c == ',' || c == ':' || c == '\\' ||
                               c == '[' || c == ']' || c == '?') {
                        -- myCurrentIndex;
                        myLexemeEndIndex = myCurrentIndex;
                        state = -1;
                    } else {
                        state = 5;
                    }
                    break;
                }
            }

        }

    }

    
Returns a lowercase version of the given string. The lowercase version
is constructed by applying Character.toLowerCase() to each character of
the given string, which maps characters to lowercase using the rules of
Unicode. This mapping is the same regardless of locale, whereas the
mapping of String.toLowerCase() may be different depending on the
default locale.
/**
     * Returns a lowercase version of the given string. The lowercase version
     * is constructed by applying Character.toLowerCase() to each character of
     * the given string, which maps characters to lowercase using the rules of
     * Unicode. This mapping is the same regardless of locale, whereas the
     * mapping of String.toLowerCase() may be different depending on the
     * default locale.
     */
    private static String toUnicodeLowerCase(String s) {
        int n = s.length();
        char[] result = new char [n];
        for (int i = 0; i < n; ++ i) {
            result[i] = Character.toLowerCase (s.charAt (i));
        }
        return new String (result);
    }

    
Returns a version of the given string with backslashes removed.
/**
     * Returns a version of the given string with backslashes removed.
     */
    private static String removeBackslashes(String s) {
        int n = s.length();
        char[] result = new char [n];
        int i;
        int j = 0;
        char c;
        for (i = 0; i < n; ++ i) {
            c = s.charAt (i);
            if (c == '\\') {
                c = s.charAt (++ i);
            }
            result[j++] = c;
        }
        return new String (result, 0, j);
    }

    
Returns a version of the string surrounded by quotes and with interior
quotes preceded by a backslash.
/**
     * Returns a version of the string surrounded by quotes and with interior
     * quotes preceded by a backslash.
     */
    private static String addQuotes(String s) {
        int n = s.length();
        int i;
        char c;
        StringBuffer result = new StringBuffer (n+2);
        result.append ('\"');
        for (i = 0; i < n; ++ i) {
            c = s.charAt (i);
            if (c == '\"') {
                result.append ('\\');
            }
            result.append (c);
        }
        result.append ('\"');
        return result.toString();
    }

    
Parses the given string into canonical pieces and stores the pieces in myPieces. 

Special rules applied:

 If the media type is text, the value of a charset parameter is
     converted to lowercase.

Params:
s –  MIME media type string.
Throws:
NullPointerException – 
    (unchecked exception) Thrown if s is null.
IllegalArgumentException – 
    (unchecked exception) Thrown if s does not obey the
    syntax for a MIME media type string./**
     * Parses the given string into canonical pieces and stores the pieces in
     * {@link #myPieces <CODE>myPieces</CODE>}.
     * <P>
     * Special rules applied:
     * <UL>
     * <LI> If the media type is text, the value of a charset parameter is
     *      converted to lowercase.
     * </UL>
     *
     * @param  s  MIME media type string.
     *
     * @exception  NullPointerException
     *     (unchecked exception) Thrown if <CODE>s</CODE> is null.
     * @exception  IllegalArgumentException
     *     (unchecked exception) Thrown if <CODE>s</CODE> does not obey the
     *     syntax for a MIME media type string.
     */
    private void parse(String s) {
        // Initialize.
        if (s == null) {
            throw new NullPointerException();
        }
        LexicalAnalyzer theLexer = new LexicalAnalyzer (s);
        int theLexemeType;
        Vector thePieces = new Vector();
        boolean mediaTypeIsText = false;
        boolean parameterNameIsCharset = false;

        // Parse media type.
        if (theLexer.getLexemeType() == TOKEN_LEXEME) {
            String mt = toUnicodeLowerCase (theLexer.getLexeme());
            thePieces.add (mt);
            theLexer.nextLexeme();
            mediaTypeIsText = mt.equals ("text");
        } else {
            throw new IllegalArgumentException();
        }
        // Parse slash.
        if (theLexer.getLexemeType() == TSPECIAL_LEXEME &&
              theLexer.getLexemeFirstCharacter() == '/') {
            theLexer.nextLexeme();
        } else {
            throw new IllegalArgumentException();
        }
        if (theLexer.getLexemeType() == TOKEN_LEXEME) {
            thePieces.add (toUnicodeLowerCase (theLexer.getLexeme()));
            theLexer.nextLexeme();
        } else {
            throw new IllegalArgumentException();
        }
        // Parse zero or more parameters.
        while (theLexer.getLexemeType() == TSPECIAL_LEXEME &&
               theLexer.getLexemeFirstCharacter() == ';') {
            // Parse semicolon.
            theLexer.nextLexeme();

            // Parse parameter name.
            if (theLexer.getLexemeType() == TOKEN_LEXEME) {
                String pn = toUnicodeLowerCase (theLexer.getLexeme());
                thePieces.add (pn);
                theLexer.nextLexeme();
                parameterNameIsCharset = pn.equals ("charset");
            } else {
                throw new IllegalArgumentException();
            }

            // Parse equals.
            if (theLexer.getLexemeType() == TSPECIAL_LEXEME &&
                theLexer.getLexemeFirstCharacter() == '=') {
                theLexer.nextLexeme();
            } else {
                throw new IllegalArgumentException();
            }

            // Parse parameter value.
            if (theLexer.getLexemeType() == TOKEN_LEXEME) {
                String pv = theLexer.getLexeme();
                thePieces.add(mediaTypeIsText && parameterNameIsCharset ?
                              toUnicodeLowerCase (pv) :
                              pv);
                theLexer.nextLexeme();
            } else if (theLexer.getLexemeType() == QUOTED_STRING_LEXEME) {
                String pv = removeBackslashes (theLexer.getLexeme());
                thePieces.add(mediaTypeIsText && parameterNameIsCharset ?
                              toUnicodeLowerCase (pv) :
                              pv);
                theLexer.nextLexeme();
            } else {
                throw new IllegalArgumentException();
            }
        }

        // Make sure we've consumed everything.
        if (theLexer.getLexemeType() != EOF_LEXEME) {
            throw new IllegalArgumentException();
        }

        // Save the pieces. Parameters are not in ascending order yet.
        int n = thePieces.size();
        myPieces = (String[]) thePieces.toArray (new String [n]);

        // Sort the parameters into ascending order using an insertion sort.
        int i, j;
        String temp;
        for (i = 4; i < n; i += 2) {
            j = 2;
            while (j < i && myPieces[j].compareTo (myPieces[i]) <= 0) {
                j += 2;
            }
            while (j < i) {
                temp = myPieces[j];
                myPieces[j] = myPieces[i];
                myPieces[i] = temp;
                temp = myPieces[j+1];
                myPieces[j+1] = myPieces[i+1];
                myPieces[i+1] = temp;
                j += 2;
            }
        }
    }
}