elementschemepointer.java

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            }
            fTokenCount++;
        }

        /**
         * Resets the current position to the head of the token list.
         */
        private void rewind() {
            fCurrentTokenIndex = 0;
        }

        /**
         * Returns true if the {@link #getNextToken()} method
         * returns a valid token.
         */
        private boolean hasMore() {
            return fCurrentTokenIndex < fTokenCount;
        }

        /**
         * Obtains the token at the current position, then advance
         * the current position by one.
         * 
         * If there's no such next token, this method throws
         * <tt>new XNIException("InvalidXPointerExpression");</tt>.
         */
        private int nextToken() throws XNIException {
            if (fCurrentTokenIndex == fTokenCount)
                reportError("XPointerElementSchemeProcessingError", null);
            return fTokens[fCurrentTokenIndex++];
        }

        /**
         * Obtains the token at the current position, without advancing
         * the current position.
         * 
         * If there's no such next token, this method throws
         * <tt>new XNIException("InvalidXPointerExpression");</tt>.
         */
        private int peekToken() throws XNIException {
            if (fCurrentTokenIndex == fTokenCount)
                reportError("XPointerElementSchemeProcessingError", null);
            return fTokens[fCurrentTokenIndex];
        }

        /**
         * Obtains the token at the current position as a String.
         * 
         * If there's no current token or if the current token
         * is not a string token, this method throws 
         * If there's no such next token, this method throws
         * <tt>new XNIException("InvalidXPointerExpression");</tt>.
         */
        private String nextTokenAsString() throws XNIException {
            String s = getTokenString(nextToken());
            if (s == null)
                reportError("XPointerElementSchemeProcessingError", null);
            return s;
        }

        /**
         * Returns the number of tokens.
         * 
         */
        private int getTokenCount() {
            return fTokenCount;
        }
    }

    /**
     * 
     * The XPointer expression scanner.  Scans the XPointer framework expression.
     * 
     * @xerces.internal
     * 
     * @version $Id: ElementSchemePointer.java,v 1.1.4.1 2005/09/08 05:25:43 sunithareddy Exp $
     */
    private class Scanner {

        /**
         * 7-bit ASCII subset
         *
         *  0   1   2   3   4   5   6   7   8   9   A   B   C   D   E   F
         *  0,  0,  0,  0,  0,  0,  0,  0,  0, HT, LF,  0,  0, CR,  0,  0,  // 0
         *  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  // 1
         * SP,  !,  ",  #,  $,  %,  &,  ',  (,  ),  *,  +,  ,,  -,  .,  /,  // 2
         *  0,  1,  2,  3,  4,  5,  6,  7,  8,  9,  :,  ;,  <,  =,  >,  ?,  // 3
         *  @,  A,  B,  C,  D,  E,  F,  G,  H,  I,  J,  K,  L,  M,  N,  O,  // 4
         *  P,  Q,  R,  S,  T,  U,  V,  W,  X,  Y,  Z,  [,  \,  ],  ^,  _,  // 5
         *  `,  a,  b,  c,  d,  e,  f,  g,  h,  i,  j,  k,  l,  m,  n,  o,  // 6
         *  p,  q,  r,  s,  t,  u,  v,  w,  x,  y,  z,  {,  |,  },  ~, DEL  // 7
         */
        private static final byte CHARTYPE_INVALID = 0, // invalid XML characters, control characters and 7F
                CHARTYPE_OTHER = 1, // A valid XML character (possibly invalid NCNameChar) that does not fall in one of the other categories
                CHARTYPE_MINUS = 2, // '-' (0x2D)
                CHARTYPE_PERIOD = 3, // '.' (0x2E)
                CHARTYPE_SLASH = 4, // '/' (0x2F)
                CHARTYPE_DIGIT = 5, // '0'-'9' (0x30 to 0x39)
                CHARTYPE_LETTER = 6, // 'A'-'Z' or 'a'-'z' (0x41 to 0x5A and 0x61 to 0x7A)
                CHARTYPE_UNDERSCORE = 7, // '_' (0x5F)
                CHARTYPE_NONASCII = 8; // Non-ASCII Unicode codepoint (>= 0x80)

        private final byte[] fASCIICharMap = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1,
                0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
                1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 4, 5, 5, 5, 5, 5,
                5, 5, 5, 5, 5, 1, 1, 1, 1, 1, 1, 1, 6, 6, 6, 6, 6, 6, 6, 6, 6,
                6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 1, 1, 1, 1,
                7, 1, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
                6, 6, 6, 6, 6, 6, 6, 1, 1, 1, 1, 1 };

        /**
         * Symbol literals
         */

        //
        // Data
        //
        /** Symbol table. */
        private SymbolTable fSymbolTable;

        //
        // Constructors
        //

        /** 
         * Constructs an XPath expression scanner. 
         *
         * @param symbolTable SymbolTable  
         */
        private Scanner(SymbolTable symbolTable) {
            // save pool and tokens
            fSymbolTable = symbolTable;

        } // <init>(SymbolTable)

        /**
         * Scans the XPointer Expression
         * 
         */
        private boolean scanExpr(SymbolTable symbolTable, Tokens tokens,
                String data, int currentOffset, int endOffset)
                throws XNIException {

            int ch;
            int nameOffset;
            String nameHandle = null;

            while (true) {
                if (currentOffset == endOffset) {
                    break;
                }

                ch = data.charAt(currentOffset);
                byte chartype = (ch >= 0x80) ? CHARTYPE_NONASCII
                        : fASCIICharMap[ch];

                // 
                // [1]    ElementSchemeData    ::=    (NCName ChildSequence?) | ChildSequence  
                // [2]    ChildSequence    ::=    ('/' [1-9] [0-9]*)+ 
                //  

                switch (chartype) {

                case CHARTYPE_SLASH:
                    // if last character is '/', break and report an error
                    if (++currentOffset == endOffset) {
                        return false;
                    }

                    addToken(tokens, Tokens.XPTRTOKEN_ELEM_CHILD);
                    ch = data.charAt(currentOffset);

                    // ChildSequence    ::=    ('/' [1-9] [0-9]*)+                    
                    int child = 0;
                    while (ch >= '0' && ch <= '9') {
                        child = (child * 10) + (ch - '0');
                        if (++currentOffset == endOffset) {
                            break;
                        }
                        ch = data.charAt(currentOffset);
                    }

                    // An invalid child sequence character
                    if (child == 0) {
                        reportError("InvalidChildSequenceCharacter",
                                new Object[] { new Character((char) ch) });
                        return false;
                    }

                    tokens.addToken(child);

                    break;

                case CHARTYPE_DIGIT:
                case CHARTYPE_LETTER:
                case CHARTYPE_MINUS:
                case CHARTYPE_NONASCII:
                case CHARTYPE_OTHER:
                case CHARTYPE_PERIOD:
                case CHARTYPE_UNDERSCORE:
                    // Scan the ShortHand Pointer NCName 
                    nameOffset = currentOffset;
                    currentOffset = scanNCName(data, endOffset, currentOffset);

                    if (currentOffset == nameOffset) {
                        //return false;
                        reportError("InvalidNCNameInElementSchemeData",
                                new Object[] { data });
                        return false;
                    }

                    if (currentOffset < endOffset) {
                        ch = data.charAt(currentOffset);
                    } else {
                        ch = -1;
                    }

                    nameHandle = symbolTable.addSymbol(data.substring(
                            nameOffset, currentOffset));
                    addToken(tokens, Tokens.XPTRTOKEN_ELEM_NCNAME);
                    tokens.addToken(nameHandle);

                    break;
                }
            }
            return true;
        }

        /** 
         * Scans a NCName.  
         * From Namespaces in XML 
         * [5] NCName ::= (Letter | '_') (NCNameChar)*
         * [6] NCNameChar ::= Letter | Digit | '.' | '-' | '_' | CombiningChar | Extender
         * 
         * @param data A String containing the XPointer expression
         * @param endOffset The int XPointer expression length  
         * @param currentOffset An int representing the current position of the XPointer expression pointer
         */
        private int scanNCName(String data, int endOffset, int currentOffset) {
            int ch = data.charAt(currentOffset);
            if (ch >= 0x80) {
                if (!XMLChar.isNameStart(ch)) {
                    return currentOffset;
                }
            } else {
                byte chartype = fASCIICharMap[ch];
                if (chartype != CHARTYPE_LETTER
                        && chartype != CHARTYPE_UNDERSCORE) {
                    return currentOffset;
                }
            }
            while (++currentOffset < endOffset) {
                ch = data.charAt(currentOffset);
                if (ch >= 0x80) {
                    if (!XMLChar.isName(ch)) {
                        break;
                    }
                } else {
                    byte chartype = fASCIICharMap[ch];
                    if (chartype != CHARTYPE_LETTER
                            && chartype != CHARTYPE_DIGIT
                            && chartype != CHARTYPE_PERIOD
                            && chartype != CHARTYPE_MINUS
                            && chartype != CHARTYPE_UNDERSCORE) {
                        break;
                    }
                }
            }
            return currentOffset;
        }

        //
        // Protected methods
        //

        /**
         * This method adds the specified token to the token list. By
         * default, this method allows all tokens. However, subclasses
         * of the XPathExprScanner can override this method in order
         * to disallow certain tokens from being used in the scanned
         * XPath expression. This is a convenient way of allowing only
         * a subset of XPath.
         */
        protected void addToken(Tokens tokens, int token) throws XNIException {
            tokens.addToken(token);
        } // addToken(int)

    } // class Scanner

}