/*
 * 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 org.apache.xml.utils;

import java.util.Arrays;


THIS IS A COPY OF THE XERCES-2J CLASS org.apache.xerces.utls.XMLChar
 
This class defines the basic properties of characters in XML 1.1. The data
in this class can be used to verify that a character is a valid
XML 1.1 character or if the character is a space, name start, or name
character.

A series of convenience methods are supplied to ease the burden
of the developer.  Using the character as an index into the XML11CHARS
array and applying the appropriate mask flag (e.g.
MASK_VALID), yields the same results as calling the
convenience methods. There is one exception: check the comments
for the isValid method for details.
Version:
$Id: XML11Char.java 468655 2006-10-28 07:12:06Z minchau $/**
 * THIS IS A COPY OF THE XERCES-2J CLASS org.apache.xerces.utls.XMLChar
 *  
 * This class defines the basic properties of characters in XML 1.1. The data
 * in this class can be used to verify that a character is a valid
 * XML 1.1 character or if the character is a space, name start, or name
 * character.
 * <p>
 * A series of convenience methods are supplied to ease the burden
 * of the developer.  Using the character as an index into the <code>XML11CHARS</code>
 * array and applying the appropriate mask flag (e.g.
 * <code>MASK_VALID</code>), yields the same results as calling the
 * convenience methods. There is one exception: check the comments
 * for the <code>isValid</code> method for details.
 *
 * @version $Id: XML11Char.java 468655 2006-10-28 07:12:06Z minchau $
 */
public class XML11Char {

    //
    // Constants
    //

    
Character flags for XML 1.1. /** Character flags for XML 1.1. */
    private static final byte XML11CHARS [] = new byte [1 << 16];

    
XML 1.1 Valid character mask. /** XML 1.1 Valid character mask. */
    public static final int MASK_XML11_VALID = 0x01;

    
XML 1.1 Space character mask. /** XML 1.1 Space character mask. */
    public static final int MASK_XML11_SPACE = 0x02;

    
XML 1.1 Name start character mask. /** XML 1.1 Name start character mask. */
    public static final int MASK_XML11_NAME_START = 0x04;

    
XML 1.1 Name character mask. /** XML 1.1 Name character mask. */
    public static final int MASK_XML11_NAME = 0x08;

    
XML 1.1 control character mask /** XML 1.1 control character mask */
    public static final int MASK_XML11_CONTROL = 0x10;

    
XML 1.1 content for external entities (valid - "special" chars - control chars) /** XML 1.1 content for external entities (valid - "special" chars - control chars) */
    public static final int MASK_XML11_CONTENT = 0x20;

    
XML namespaces 1.1 NCNameStart /** XML namespaces 1.1 NCNameStart */
    public static final int MASK_XML11_NCNAME_START = 0x40;

    
XML namespaces 1.1 NCName /** XML namespaces 1.1 NCName */
    public static final int MASK_XML11_NCNAME = 0x80;
    
    
XML 1.1 content for internal entities (valid - "special" chars) /** XML 1.1 content for internal entities (valid - "special" chars) */
    public static final int MASK_XML11_CONTENT_INTERNAL = MASK_XML11_CONTROL | MASK_XML11_CONTENT; 

    //
    // Static initialization
    //

    static {
    	
        // Initializing the Character Flag Array
        // Code generated by: XML11CharGenerator.
        
        Arrays.fill(XML11CHARS, 1, 9, (byte) 17 ); // Fill 8 of value (byte) 17
        XML11CHARS[9] = 35;
        XML11CHARS[10] = 3;
        Arrays.fill(XML11CHARS, 11, 13, (byte) 17 ); // Fill 2 of value (byte) 17
        XML11CHARS[13] = 3;
        Arrays.fill(XML11CHARS, 14, 32, (byte) 17 ); // Fill 18 of value (byte) 17
        XML11CHARS[32] = 35;
        Arrays.fill(XML11CHARS, 33, 38, (byte) 33 ); // Fill 5 of value (byte) 33
        XML11CHARS[38] = 1;
        Arrays.fill(XML11CHARS, 39, 45, (byte) 33 ); // Fill 6 of value (byte) 33
        Arrays.fill(XML11CHARS, 45, 47, (byte) -87 ); // Fill 2 of value (byte) -87
        XML11CHARS[47] = 33;
        Arrays.fill(XML11CHARS, 48, 58, (byte) -87 ); // Fill 10 of value (byte) -87
        XML11CHARS[58] = 45;
        XML11CHARS[59] = 33;
        XML11CHARS[60] = 1;
        Arrays.fill(XML11CHARS, 61, 65, (byte) 33 ); // Fill 4 of value (byte) 33
        Arrays.fill(XML11CHARS, 65, 91, (byte) -19 ); // Fill 26 of value (byte) -19
        Arrays.fill(XML11CHARS, 91, 93, (byte) 33 ); // Fill 2 of value (byte) 33
        XML11CHARS[93] = 1;
        XML11CHARS[94] = 33;
        XML11CHARS[95] = -19;
        XML11CHARS[96] = 33;
        Arrays.fill(XML11CHARS, 97, 123, (byte) -19 ); // Fill 26 of value (byte) -19
        Arrays.fill(XML11CHARS, 123, 127, (byte) 33 ); // Fill 4 of value (byte) 33
        Arrays.fill(XML11CHARS, 127, 133, (byte) 17 ); // Fill 6 of value (byte) 17
        XML11CHARS[133] = 35;
        Arrays.fill(XML11CHARS, 134, 160, (byte) 17 ); // Fill 26 of value (byte) 17
        Arrays.fill(XML11CHARS, 160, 183, (byte) 33 ); // Fill 23 of value (byte) 33
        XML11CHARS[183] = -87;
        Arrays.fill(XML11CHARS, 184, 192, (byte) 33 ); // Fill 8 of value (byte) 33
        Arrays.fill(XML11CHARS, 192, 215, (byte) -19 ); // Fill 23 of value (byte) -19
        XML11CHARS[215] = 33;
        Arrays.fill(XML11CHARS, 216, 247, (byte) -19 ); // Fill 31 of value (byte) -19
        XML11CHARS[247] = 33;
        Arrays.fill(XML11CHARS, 248, 768, (byte) -19 ); // Fill 520 of value (byte) -19
        Arrays.fill(XML11CHARS, 768, 880, (byte) -87 ); // Fill 112 of value (byte) -87
        Arrays.fill(XML11CHARS, 880, 894, (byte) -19 ); // Fill 14 of value (byte) -19
        XML11CHARS[894] = 33;
        Arrays.fill(XML11CHARS, 895, 8192, (byte) -19 ); // Fill 7297 of value (byte) -19
        Arrays.fill(XML11CHARS, 8192, 8204, (byte) 33 ); // Fill 12 of value (byte) 33
        Arrays.fill(XML11CHARS, 8204, 8206, (byte) -19 ); // Fill 2 of value (byte) -19
        Arrays.fill(XML11CHARS, 8206, 8232, (byte) 33 ); // Fill 26 of value (byte) 33
        XML11CHARS[8232] = 35;
        Arrays.fill(XML11CHARS, 8233, 8255, (byte) 33 ); // Fill 22 of value (byte) 33
        Arrays.fill(XML11CHARS, 8255, 8257, (byte) -87 ); // Fill 2 of value (byte) -87
        Arrays.fill(XML11CHARS, 8257, 8304, (byte) 33 ); // Fill 47 of value (byte) 33
        Arrays.fill(XML11CHARS, 8304, 8592, (byte) -19 ); // Fill 288 of value (byte) -19
        Arrays.fill(XML11CHARS, 8592, 11264, (byte) 33 ); // Fill 2672 of value (byte) 33
        Arrays.fill(XML11CHARS, 11264, 12272, (byte) -19 ); // Fill 1008 of value (byte) -19
        Arrays.fill(XML11CHARS, 12272, 12289, (byte) 33 ); // Fill 17 of value (byte) 33
        Arrays.fill(XML11CHARS, 12289, 55296, (byte) -19 ); // Fill 43007 of value (byte) -19
        Arrays.fill(XML11CHARS, 57344, 63744, (byte) 33 ); // Fill 6400 of value (byte) 33
        Arrays.fill(XML11CHARS, 63744, 64976, (byte) -19 ); // Fill 1232 of value (byte) -19
        Arrays.fill(XML11CHARS, 64976, 65008, (byte) 33 ); // Fill 32 of value (byte) 33
        Arrays.fill(XML11CHARS, 65008, 65534, (byte) -19 ); // Fill 526 of value (byte) -19

    } // <clinit>()

    //
    // Public static methods
    //

    
Returns true if the specified character is a space character
as amdended in the XML 1.1 specification.
Params:
c – The character to check./**
     * Returns true if the specified character is a space character
     * as amdended in the XML 1.1 specification.
     *
     * @param c The character to check.
     */
    public static boolean isXML11Space(int c) {
        return (c < 0x10000 && (XML11CHARS[c] & MASK_XML11_SPACE) != 0);
    } // isXML11Space(int):boolean

    
Returns true if the specified character is valid. This method
also checks the surrogate character range from 0x10000 to 0x10FFFF.

If the program chooses to apply the mask directly to the
XML11CHARS array, then they are responsible for checking
the surrogate character range.
Params:
c – The character to check./**
     * Returns true if the specified character is valid. This method
     * also checks the surrogate character range from 0x10000 to 0x10FFFF.
     * <p>
     * If the program chooses to apply the mask directly to the
     * <code>XML11CHARS</code> array, then they are responsible for checking
     * the surrogate character range.
     *
     * @param c The character to check.
     */
    public static boolean isXML11Valid(int c) {
        return (c < 0x10000 && (XML11CHARS[c] & MASK_XML11_VALID) != 0) 
                || (0x10000 <= c && c <= 0x10FFFF);
    } // isXML11Valid(int):boolean

    
Returns true if the specified character is invalid.
Params:
c – The character to check./**
     * Returns true if the specified character is invalid.
     *
     * @param c The character to check.
     */
    public static boolean isXML11Invalid(int c) {
        return !isXML11Valid(c);
    } // isXML11Invalid(int):boolean

    
Returns true if the specified character is valid and permitted outside
of a character reference.  
That is, this method will return false for the same set as
isXML11Valid, except it also reports false for "control characters".
Params:
c – The character to check./**
     * Returns true if the specified character is valid and permitted outside
     * of a character reference.  
     * That is, this method will return false for the same set as
     * isXML11Valid, except it also reports false for "control characters".
     *
     * @param c The character to check.
     */
    public static boolean isXML11ValidLiteral(int c) {
        return ((c < 0x10000 && ((XML11CHARS[c] & MASK_XML11_VALID) != 0 && (XML11CHARS[c] & MASK_XML11_CONTROL) == 0))
            || (0x10000 <= c && c <= 0x10FFFF)); 
    } // isXML11ValidLiteral(int):boolean

    
Returns true if the specified character can be considered 
content in an external parsed entity.
Params:
c – The character to check./**
     * Returns true if the specified character can be considered 
     * content in an external parsed entity.
     *
     * @param c The character to check.
     */
    public static boolean isXML11Content(int c) {
        return (c < 0x10000 && (XML11CHARS[c] & MASK_XML11_CONTENT) != 0) ||
               (0x10000 <= c && c <= 0x10FFFF);
    } // isXML11Content(int):boolean
    
    
Returns true if the specified character can be considered 
content in an internal parsed entity.
Params:
c – The character to check./**
     * Returns true if the specified character can be considered 
     * content in an internal parsed entity.
     *
     * @param c The character to check.
     */
    public static boolean isXML11InternalEntityContent(int c) {
        return (c < 0x10000 && (XML11CHARS[c] & MASK_XML11_CONTENT_INTERNAL) != 0) ||
               (0x10000 <= c && c <= 0x10FFFF);
    } // isXML11InternalEntityContent(int):boolean

    
Returns true if the specified character is a valid name start
character as defined by production [4] in the XML 1.1
specification.
Params:
c – The character to check./**
     * Returns true if the specified character is a valid name start
     * character as defined by production [4] in the XML 1.1
     * specification.
     *
     * @param c The character to check.
     */
    public static boolean isXML11NameStart(int c) {
        return (c < 0x10000 && (XML11CHARS[c] & MASK_XML11_NAME_START) != 0)
            || (0x10000 <= c && c < 0xF0000);
    } // isXML11NameStart(int):boolean

    
Returns true if the specified character is a valid name
character as defined by production [4a] in the XML 1.1
specification.
Params:
c – The character to check./**
     * Returns true if the specified character is a valid name
     * character as defined by production [4a] in the XML 1.1
     * specification.
     *
     * @param c The character to check.
     */
    public static boolean isXML11Name(int c) {
        return (c < 0x10000 && (XML11CHARS[c] & MASK_XML11_NAME) != 0) 
            || (c >= 0x10000 && c < 0xF0000);
    } // isXML11Name(int):boolean

    
Returns true if the specified character is a valid NCName start
character as defined by production [4] in Namespaces in XML
1.1 recommendation.
Params:
c – The character to check./**
     * Returns true if the specified character is a valid NCName start
     * character as defined by production [4] in Namespaces in XML
     * 1.1 recommendation.
     *
     * @param c The character to check.
     */
    public static boolean isXML11NCNameStart(int c) {
        return (c < 0x10000 && (XML11CHARS[c] & MASK_XML11_NCNAME_START) != 0)
            || (0x10000 <= c && c < 0xF0000);
    } // isXML11NCNameStart(int):boolean

    
Returns true if the specified character is a valid NCName
character as defined by production [5] in Namespaces in XML
1.1 recommendation.
Params:
c – The character to check./**
     * Returns true if the specified character is a valid NCName
     * character as defined by production [5] in Namespaces in XML
     * 1.1 recommendation.
     *
     * @param c The character to check.
     */
    public static boolean isXML11NCName(int c) {
        return (c < 0x10000 && (XML11CHARS[c] & MASK_XML11_NCNAME) != 0)
            || (0x10000 <= c && c < 0xF0000);
    } // isXML11NCName(int):boolean
    
    
Returns whether the given character is a valid 
high surrogate for a name character. This includes
all high surrogates for characters [0x10000-0xEFFFF].
In other words everything excluding planes 15 and 16.
Params:
c – The character to check./**
     * Returns whether the given character is a valid 
     * high surrogate for a name character. This includes
     * all high surrogates for characters [0x10000-0xEFFFF].
     * In other words everything excluding planes 15 and 16.
     *
     * @param c The character to check.
     */
    public static boolean isXML11NameHighSurrogate(int c) {
        return (0xD800 <= c && c <= 0xDB7F);
    }

    /*
     * [5] Name ::= NameStartChar NameChar*
     */
    
Check to see if a string is a valid Name according to [5]
in the XML 1.1 Recommendation
Params:
name – string to check
Returns:
true if name is a valid Name/**
     * Check to see if a string is a valid Name according to [5]
     * in the XML 1.1 Recommendation
     *
     * @param name string to check
     * @return true if name is a valid Name
     */
    public static boolean isXML11ValidName(String name) {
        int length = name.length();
        if (length == 0)
            return false;
        int i = 1;
        char ch = name.charAt(0);
        if( !isXML11NameStart(ch) ) {
            if ( length > 1 && isXML11NameHighSurrogate(ch) ) {
                char ch2 = name.charAt(1);
                if ( !XMLChar.isLowSurrogate(ch2) || 
                     !isXML11NameStart(XMLChar.supplemental(ch, ch2)) ) {
                    return false;
                }
                i = 2;
            }
            else {
                return false;
            }
        }
        while (i < length) {
            ch = name.charAt(i);
            if ( !isXML11Name(ch) ) {
                if ( ++i < length && isXML11NameHighSurrogate(ch) ) {
                    char ch2 = name.charAt(i);
                    if ( !XMLChar.isLowSurrogate(ch2) || 
                         !isXML11Name(XMLChar.supplemental(ch, ch2)) ) {
                        return false;
                    }
                }
                else {
                    return false;
                }
            }
            ++i;
        }
        return true;
    } // isXML11ValidName(String):boolean
    

    /*
     * from the namespace 1.1 rec
     * [4] NCName ::= NCNameStartChar NCNameChar*
     */
    
Check to see if a string is a valid NCName according to [4]
from the XML Namespaces 1.1 Recommendation
Params:
ncName – string to check
Returns:
true if name is a valid NCName/**
     * Check to see if a string is a valid NCName according to [4]
     * from the XML Namespaces 1.1 Recommendation
     *
     * @param ncName string to check
     * @return true if name is a valid NCName
     */
    public static boolean isXML11ValidNCName(String ncName) {
        int length = ncName.length();
        if (length == 0)
            return false;
        int i = 1;
        char ch = ncName.charAt(0);
        if( !isXML11NCNameStart(ch) ) {
            if ( length > 1 && isXML11NameHighSurrogate(ch) ) {
                char ch2 = ncName.charAt(1);
                if ( !XMLChar.isLowSurrogate(ch2) || 
                     !isXML11NCNameStart(XMLChar.supplemental(ch, ch2)) ) {
                    return false;
                }
                i = 2;
            }
            else {
                return false;
            }
        }
        while (i < length) {
            ch = ncName.charAt(i);
            if ( !isXML11NCName(ch) ) {
                if ( ++i < length && isXML11NameHighSurrogate(ch) ) {
                    char ch2 = ncName.charAt(i);
                    if ( !XMLChar.isLowSurrogate(ch2) || 
                         !isXML11NCName(XMLChar.supplemental(ch, ch2)) ) {
                        return false;
                    }
                }
                else {
                    return false;
                }
            }
            ++i;
        }
        return true;
    } // isXML11ValidNCName(String):boolean

    /*
     * [7] Nmtoken ::= (NameChar)+
     */
    
Check to see if a string is a valid Nmtoken according to [7]
in the XML 1.1 Recommendation
Params:
nmtoken – string to check
Returns:
true if nmtoken is a valid Nmtoken/**
     * Check to see if a string is a valid Nmtoken according to [7]
     * in the XML 1.1 Recommendation
     *
     * @param nmtoken string to check
     * @return true if nmtoken is a valid Nmtoken 
     */
    public static boolean isXML11ValidNmtoken(String nmtoken) {
        int length = nmtoken.length();
        if (length == 0)
            return false;
        for (int i = 0; i < length; ++i ) {
            char ch = nmtoken.charAt(i);
            if( !isXML11Name(ch) ) {
                if ( ++i < length && isXML11NameHighSurrogate(ch) ) {
                    char ch2 = nmtoken.charAt(i);
                    if ( !XMLChar.isLowSurrogate(ch2) || 
                         !isXML11Name(XMLChar.supplemental(ch, ch2)) ) {
                        return false;
                    }
                }
                else {
                    return false;
                }
            }
        }
        return true;
    } // isXML11ValidName(String):boolean
    
    
Simple check to determine if qname is legal. If it returns false
then str is illegal; if it returns true then 
str is legal.
/**
      * Simple check to determine if qname is legal. If it returns false
      * then <param>str</param> is illegal; if it returns true then 
      * <param>str</param> is legal.
      */
     public static boolean isXML11ValidQName(String str) {

        final int colon = str.indexOf(':');

        if (colon == 0 || colon == str.length() - 1) {
            return false;
        }
       
        if (colon > 0) {
            final String prefix = str.substring(0,colon);
            final String localPart = str.substring(colon+1);
            return isXML11ValidNCName(prefix) && isXML11ValidNCName(localPart);
        }
        else {
            return isXML11ValidNCName(str);
        }
     }

} // class XML11Char