/*

 */

/*

 * 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.

 */

package com.sun.org.apache.xml.internal.serializer;

import com.sun.org.apache.xml.internal.serializer.utils.MsgKey;

import com.sun.org.apache.xml.internal.serializer.utils.SystemIDResolver;

import com.sun.org.apache.xml.internal.serializer.utils.Utils;

import com.sun.org.apache.xml.internal.serializer.utils.WrappedRuntimeException;

import java.io.BufferedReader;

import java.io.InputStream;

import java.io.InputStreamReader;

import java.io.UnsupportedEncodingException;

import java.net.URL;

import java.util.Enumeration;

import java.util.HashMap;

import java.util.Locale;

import java.util.PropertyResourceBundle;

import java.util.ResourceBundle;

import javax.xml.transform.TransformerException;

/**

 * This class provides services that tell if a character should have

 * special treatement, such as entity reference substitution or normalization

 * of a newline character.  It also provides character to entity reference

 * lookup.

 *

 * DEVELOPERS: See Known Issue in the constructor.

 *

 * @xsl.usage internal

 */

final class CharInfo

{

    /** Given a character, lookup a String to output (e.g. a decorated entity reference). */

    private HashMap m_charToString = new HashMap();

    /**

     * The name of the HTML entities file.

     * If specified, the file will be resource loaded with the default class loader.

     */

    public static final String HTML_ENTITIES_RESOURCE =

                "com.sun.org.apache.xml.internal.serializer.HTMLEntities";

    /**

     * The name of the XML entities file.

     * If specified, the file will be resource loaded with the default class loader.

     */

    public static final String XML_ENTITIES_RESOURCE =

                "com.sun.org.apache.xml.internal.serializer.XMLEntities";

    /** The horizontal tab character, which the parser should always normalize. */

    public static final char S_HORIZONAL_TAB = 0x09;

    /** The linefeed character, which the parser should always normalize. */

    public static final char S_LINEFEED = 0x0A;

    /** The carriage return character, which the parser should always normalize. */

    public static final char S_CARRIAGERETURN = 0x0D;

    /** This flag is an optimization for HTML entities. It false if entities

     * other than quot (34), amp (38), lt (60) and gt (62) are defined

     * in the range 0 to 127.

     * @xsl.usage internal

     */

    final boolean onlyQuotAmpLtGt;

    /** Copy the first 0,1 ... ASCII_MAX values into an array */

    private static final int ASCII_MAX = 128;

    /** Array of values is faster access than a set of bits

     * to quickly check ASCII characters in attribute values.

     */

    private boolean[] isSpecialAttrASCII = new boolean[ASCII_MAX];

    /** Array of values is faster access than a set of bits

     * to quickly check ASCII characters in text nodes.

     */

    private boolean[] isSpecialTextASCII = new boolean[ASCII_MAX];

    private boolean[] isCleanTextASCII = new boolean[ASCII_MAX];

    /** An array of bits to record if the character is in the set.

     * Although information in this array is complete, the

     * isSpecialAttrASCII array is used first because access to its values

     * is common and faster.

     */

    private int array_of_bits[] = createEmptySetOfIntegers(65535);

    // 5 for 32 bit words,  6 for 64 bit words ...

    /*

     * This constant is used to shift an integer to quickly

     * calculate which element its bit is stored in.

     * 5 for 32 bit words (int) ,  6 for 64 bit words (long)

     */

    private static final int SHIFT_PER_WORD = 5;

    /*

     * A mask to get the low order bits which are used to

     * calculate the value of the bit within a given word,

     * that will represent the presence of the integer in the

     * set.

     *

     * 0x1F for 32 bit words (int),

     * or 0x3F for 64 bit words (long)

     */

    private static final int LOW_ORDER_BITMASK = 0x1f;

    /*

     * This is used for optimizing the lookup of bits representing

     * the integers in the set. It is the index of the first element

     * in the array array_of_bits[] that is not used.

     */

    private int firstWordNotUsed;

    /**

     * Constructor that reads in a resource file that describes the mapping of

     * characters to entity references.

     * This constructor is private, just to force the use

     * of the getCharInfo(entitiesResource) factory

     *

     * Resource files must be encoded in UTF-8 and can either be properties

     * files with a .properties extension assumed.  Alternatively, they can

     * have the following form, with no particular extension assumed:

     *

     * <pre>

     * # First char # is a comment

     * Entity numericValue

     * quot 34

     * amp 38

     * </pre>

     *

     * @param entitiesResource Name of properties or resource file that should

     * be loaded, which describes that mapping of characters to entity

     * references.

     */

    private CharInfo(String entitiesResource, String method)

    {

        this(entitiesResource, method, false);

    }

    private CharInfo(String entitiesResource, String method, boolean internal)

    {

        ResourceBundle entities = null;

        boolean noExtraEntities = true;

        // Make various attempts to interpret the parameter as a properties

        // file or resource file, as follows:

        //

        //   1) attempt to load .properties file using ResourceBundle

        //   2) try using the class loader to find the specified file a resource

        //      file

        //   3) try treating the resource a URI

        try {

            if (internal) {

                // Load entity property files by using PropertyResourceBundle,

                // cause of security issure for applets

                entities = PropertyResourceBundle.getBundle(entitiesResource);

            } else {

                ClassLoader cl = SecuritySupport.getContextClassLoader();

                if (cl != null) {

                    entities = PropertyResourceBundle.getBundle(entitiesResource,

                            Locale.getDefault(), cl);

                }

            }

        } catch (Exception e) {}

        if (entities != null) {

            Enumeration keys = entities.getKeys();

            while (keys.hasMoreElements()){

                String name = (String) keys.nextElement();

                String value = entities.getString(name);

                int code = Integer.parseInt(value);

                defineEntity(name, (char) code);

                if (extraEntity(code))

                    noExtraEntities = false;

            }

            set(S_LINEFEED);

            set(S_CARRIAGERETURN);

        } else {

            InputStream is = null;

            String err = null;

            // Load user specified resource file by using URL loading, it

            // requires a valid URI as parameter

            try {

                if (internal) {

                    is = CharInfo.class.getResourceAsStream(entitiesResource);

                } else {

                    ClassLoader cl = SecuritySupport.getContextClassLoader();

                    if (cl != null) {

                        try {

                            is = cl.getResourceAsStream(entitiesResource);

                        } catch (Exception e) {

                            err = e.getMessage();

                        }

                    }

                    if (is == null) {

                        try {

                            URL url = new URL(entitiesResource);

                            is = url.openStream();

                        } catch (Exception e) {

                            err = e.getMessage();

                        }

                    }

                }

                if (is == null) {

                    throw new RuntimeException(

                        Utils.messages.createMessage(

                            MsgKey.ER_RESOURCE_COULD_NOT_FIND,

                            new Object[] {entitiesResource, err}));

                }

                // Fix Bugzilla#4000: force reading in UTF-8

                //  This creates the de facto standard that Xalan's resource

                //  files must be encoded in UTF-8. This should work in all

                // JVMs.

                //

                // %REVIEW% KNOWN ISSUE: IT FAILS IN MICROSOFT VJ++, which

                // didn't implement the UTF-8 encoding. Theoretically, we should

                // simply let it fail in that case, since the JVM is obviously

                // broken if it doesn't support such a basic standard.  But

                // since there are still some users attempting to use VJ++ for

                // development, we have dropped in a fallback which makes a

                // second attempt using the platform's default encoding. In VJ++

                // this is apparently ASCII, which is subset of UTF-8... and

                // since the strings we'll be reading here are also primarily

                // limited to the 7-bit ASCII range (at least, in English

                // versions of Xalan), this should work well enough to keep us

                // on the air until we're ready to officially decommit from

                // VJ++.

                BufferedReader reader;

                try {

                    reader = new BufferedReader(new InputStreamReader(is, "UTF-8"));

                } catch (UnsupportedEncodingException e) {

                    reader = new BufferedReader(new InputStreamReader(is));

                }

                String line = reader.readLine();

                while (line != null) {

                    if (line.length() == 0 || line.charAt(0) == '#') {

                        line = reader.readLine();

                        continue;

                    }

                    int index = line.indexOf(' ');

                    if (index > 1) {

                        String name = line.substring(0, index);

                        ++index;

                        if (index < line.length()) {

                            String value = line.substring(index);

                            index = value.indexOf(' ');

                            if (index > 0) {

                                value = value.substring(0, index);

                            }

                            int code = Integer.parseInt(value);

                            defineEntity(name, (char) code);

                            if (extraEntity(code))

                                noExtraEntities = false;

                        }

                    }

                    line = reader.readLine();

                }

                is.close();

                set(S_LINEFEED);

                set(S_CARRIAGERETURN);

            } catch (Exception e) {

                throw new RuntimeException(

                    Utils.messages.createMessage(

                        MsgKey.ER_RESOURCE_COULD_NOT_LOAD,

                        new Object[] { entitiesResource,

                                       e.toString(),

                                       entitiesResource,

                                       e.toString()}));

            } finally {

                if (is != null) {

                    try {

                        is.close();

                    } catch (Exception except) {}

                }

            }

        }

        /* initialize the array isCleanTextASCII[] with a cache of values

         * for use by ToStream.character(char[], int , int)

         * and the array isSpecialTextASCII[] with the opposite values

         * (all in the name of performance!)

         */

        for (int ch = 0; ch <ASCII_MAX; ch++)

        if((((0x20 <= ch || (0x0A == ch || 0x0D == ch || 0x09 == ch)))

             && (!get(ch))) || ('"' == ch))

        {

            isCleanTextASCII[ch] = true;

            isSpecialTextASCII[ch] = false;

        }

        else {

            isCleanTextASCII[ch] = false;

            isSpecialTextASCII[ch] = true;

        }

        onlyQuotAmpLtGt = noExtraEntities;

        // initialize the array with a cache of the BitSet values

        for (int i=0; i<ASCII_MAX; i++)

            isSpecialAttrASCII[i] = get(i);

        /* Now that we've used get(ch) just above to initialize the

         * two arrays we will change by adding a tab to the set of

         * special chars for XML (but not HTML!).

         * We do this because a tab is always a

         * special character in an XML attribute,

         * but only a special character in XML text

         * if it has an entity defined for it.

         * This is the reason for this delay.

         */

        if (Method.XML.equals(method))

        {

            isSpecialAttrASCII[S_HORIZONAL_TAB] = true;

        }

    }

    /**

     * Defines a new character reference. The reference's name and value are

     * supplied. Nothing happens if the character reference is already defined.

     * <p>Unlike internal entities, character references are a string to single

     * character mapping. They are used to map non-ASCII characters both on

     * parsing and printing, primarily for HTML documents. '<amp;' is an

     * example of a character reference.</p>

     *

     * @param name The entity's name

     * @param value The entity's value

     */

    private void defineEntity(String name, char value)

    {

        StringBuilder sb = new StringBuilder("&");

        sb.append(name);

        sb.append(';');

        String entityString = sb.toString();

        defineChar2StringMapping(entityString, value);

    }

    /**

     * Map a character to a String. For example given

     * the character '>' this method would return the fully decorated

     * entity name "<".

     * Strings for entity references are loaded from a properties file,

     * but additional mappings defined through calls to defineChar2String()

     * are possible. Such entity reference mappings could be over-ridden.

     *

     * This is reusing a stored key object, in an effort to avoid

     * heap activity. Unfortunately, that introduces a threading risk.

     * Simplest fix for now is to make it a synchronized method, or to give

     * up the reuse; I see very little performance difference between them.

     * Long-term solution would be to replace the hashtable with a sparse array

     * keyed directly from the character's integer value; see DTM's

     * string pool for a related solution.

     *

     * @param value The character that should be resolved to

     * a String, e.g. resolve '>' to  "<".

     *

     * @return The String that the character is mapped to, or null if not found.

     * @xsl.usage internal

     */

    String getOutputStringForChar(char value)

    {

        CharKey charKey = new CharKey();

        charKey.setChar(value);

        return (String) m_charToString.get(charKey);

    }

    /**

     * Tell if the character argument that is from

     * an attribute value should have special treatment.

     *

     * @param value the value of a character that is in an attribute value

     * @return true if the character should have any special treatment,

     * such as when writing out attribute values,

     * or entity references.

     * @xsl.usage internal

     */

    final boolean isSpecialAttrChar(int value)

    {

        // for performance try the values in the boolean array first,

        // this is faster access than the BitSet for common ASCII values

        if (value < ASCII_MAX)

            return isSpecialAttrASCII[value];

        // rather than java.util.BitSet, our private

        // implementation is faster (and less general).

        return get(value);

    }

    /**

     * Tell if the character argument that is from a

     * text node should have special treatment.

     *

     * @param value the value of a character that is in a text node

     * @return true if the character should have any special treatment,

     * such as when writing out attribute values,

     * or entity references.

     * @xsl.usage internal

     */

    final boolean isSpecialTextChar(int value)

    {

        // for performance try the values in the boolean array first,

        // this is faster access than the BitSet for common ASCII values

        if (value < ASCII_MAX)

            return isSpecialTextASCII[value];

        // rather than java.util.BitSet, our private

        // implementation is faster (and less general).

        return get(value);

    }

    /**

     * This method is used to determine if an ASCII character in

     * a text node (not an attribute value) is "clean".

     * @param value the character to check (0 to 127).

     * @return true if the character can go to the writer as-is

     * @xsl.usage internal

     */

    final boolean isTextASCIIClean(int value)

    {

        return isCleanTextASCII[value];

    }

    /**

     * Read an internal resource file that describes the mapping of

     * characters to entity references; Construct a CharInfo object.

     *

     * @param entitiesFileName Name of entities resource file that should

     * be loaded, which describes the mapping of characters to entity references.

     * @param method the output method type, which should be one of "xml", "html", and "text".

     * @return an instance of CharInfo

     *

     * @xsl.usage internal

     */

    static CharInfo getCharInfoInternal(String entitiesFileName, String method)

    {

        CharInfo charInfo = (CharInfo) m_getCharInfoCache.get(entitiesFileName);

        if (charInfo != null) {

            return charInfo;

        }

        charInfo = new CharInfo(entitiesFileName, method, true);

        m_getCharInfoCache.put(entitiesFileName, charInfo);

        return charInfo;

    }

    /**

     * Constructs a CharInfo object using the following process to try reading

     * the entitiesFileName parameter:

     *

     *   1) attempt to load it as a ResourceBundle

     *   2) try using the class loader to find the specified file

     *   3) try opening it as an URI

     *

     * In case of 2 and 3, the resource file must be encoded in UTF-8 and have the

     * following format:

     * <pre>

     * # First char # is a comment

     * Entity numericValue

     * quot 34

     * amp 38

     * </pre>

     *

     * @param entitiesFileName Name of entities resource file that should

     * be loaded, which describes the mapping of characters to entity references.

     * @param method the output method type, which should be one of "xml", "html", and "text".

     * @return an instance of CharInfo

     */