/*

 */

/*

 * 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.xerces.internal.impl.xpath.regex;

import java.util.Locale;

import java.util.MissingResourceException;

import java.util.ResourceBundle;

/**

 * A Regular Expression Parser.

 *

 * @xerces.internal

 *

 */

class RegexParser {

    static final int T_CHAR = 0;

    static final int T_EOF = 1;

    static final int T_OR = 2;                  // '|'

    static final int T_STAR = 3;                // '*'

    static final int T_PLUS = 4;                // '+'

    static final int T_QUESTION = 5;            // '?'

    static final int T_LPAREN = 6;              // '('

    static final int T_RPAREN = 7;              // ')'

    static final int T_DOT = 8;                 // '.'

    static final int T_LBRACKET = 9;            // '['

    static final int T_BACKSOLIDUS = 10;        // '\'

    static final int T_CARET = 11;              // '^'

    static final int T_DOLLAR = 12;             // '$'

    static final int T_LPAREN2 = 13;            // '(?:'

    static final int T_LOOKAHEAD = 14;          // '(?='

    static final int T_NEGATIVELOOKAHEAD = 15;  // '(?!'

    static final int T_LOOKBEHIND = 16;         // '(?<='

    static final int T_NEGATIVELOOKBEHIND = 17; // '(?<!'

    static final int T_INDEPENDENT = 18;        // '(?>'

    static final int T_SET_OPERATIONS = 19;     // '(?['

    static final int T_POSIX_CHARCLASS_START = 20; // '[:' in a character class

    static final int T_COMMENT = 21;            // '(?#'

    static final int T_MODIFIERS = 22;          // '(?' [\-,a-z,A-Z]

    static final int T_CONDITION = 23;          // '(?('

    static final int T_XMLSCHEMA_CC_SUBTRACTION = 24; // '-[' in a character class

    static class ReferencePosition {

        int refNumber;

        int position;

        ReferencePosition(int n, int pos) {

            this.refNumber = n;

            this.position = pos;

        }

    }

    int offset;

    String regex;

    int regexlen;

    int options;

    ResourceBundle resources;

    int chardata;

    int nexttoken;

    static protected final int S_NORMAL = 0;

    static protected final int S_INBRACKETS = 1;

    static protected final int S_INXBRACKETS = 2;

    int context = S_NORMAL;

    int parenOpened = 1;

    int parennumber = 1;

    boolean hasBackReferences;

    ArrayList<ReferencePosition> references = null;

    public RegexParser() {

        this.setLocale(Locale.getDefault());

    }

    public RegexParser(Locale locale) {

        this.setLocale(locale);

    }

    public void setLocale(Locale locale) {

        try {

            if (locale != null) {

                this.resources = SecuritySupport.getResourceBundle("com.sun.org.apache.xerces.internal.impl.xpath.regex.message", locale);

            }

            else {

                this.resources = SecuritySupport.getResourceBundle("com.sun.org.apache.xerces.internal.impl.xpath.regex.message");

            }

        }

        catch (MissingResourceException mre) {

            throw new RuntimeException("Installation Problem???  Couldn't load messages: "

                                       + mre.getMessage());

        }

    }

    final ParseException ex(String key, int loc) {

        return new ParseException(this.resources.getString(key), loc);

    }

    protected final boolean isSet(int flag) {

        return (this.options & flag) == flag;

    }

    Token parse(String regex, int options) throws ParseException {

        this.options = options;

        this.offset = 0;

        this.setContext(S_NORMAL);

        this.parennumber = 1;

        this.parenOpened = 1;

        this.hasBackReferences = false;

        this.regex = regex;

        if (this.isSet(RegularExpression.EXTENDED_COMMENT))

            this.regex = REUtil.stripExtendedComment(this.regex);

        this.regexlen = this.regex.length();

        this.next();

        Token ret = this.parseRegex();

        if (this.offset != this.regexlen)

            throw ex("parser.parse.1", this.offset);

        if (this.read() != T_EOF) {

            throw ex("parser.parse.1", this.offset-1);

        }

        if (this.references != null) {

            for (int i = 0;  i < this.references.size();  i ++) {

                ReferencePosition position = this.references.get(i);

                if (this.parennumber <= position.refNumber)

                    throw ex("parser.parse.2", position.position);

            }

            this.references.clear();

        }

        return ret;

    }

    /*

    public RegularExpression createRegex(String regex, int options) throws ParseException {

        Token tok = this.parse(regex, options);

        return new RegularExpression(regex, tok, this.parennumber, this.hasBackReferences, options);

    }

    */

    protected final void setContext(int con) {

        this.context = con;

    }

    final int read() {

        return this.nexttoken;

    }

    @SuppressWarnings("fallthrough")

    final void next() {

        if (this.offset >= this.regexlen) {

            this.chardata = -1;

            this.nexttoken = T_EOF;

            return;

        }

        int ret;

        int ch = this.regex.charAt(this.offset++);

        this.chardata = ch;

        if (this.context == S_INBRACKETS) {

            // In a character class, this.chardata has one character, that is to say,

            // a pair of surrogates is composed and stored to this.chardata.

            switch (ch) {

              case '\\':

                ret = T_BACKSOLIDUS;

                if (this.offset >= this.regexlen)

                    throw ex("parser.next.1", this.offset-1);

                this.chardata = this.regex.charAt(this.offset++);

                break;

              case '-':

                // Allow character class subtraction (regardless of whether we are in

                // XML Schema mode or not)

                if (this.offset < this.regexlen && this.regex.charAt(this.offset) == '[') {

                    this.offset++;

                    ret = T_XMLSCHEMA_CC_SUBTRACTION;

                } else

                    ret = T_CHAR;

                break;

              case '[':

                if (!this.isSet(RegularExpression.XMLSCHEMA_MODE)

                    && this.offset < this.regexlen && this.regex.charAt(this.offset) == ':') {

                    this.offset++;

                    ret = T_POSIX_CHARCLASS_START;

                    break;

                } // Through down

              default:

                if (REUtil.isHighSurrogate(ch) && this.offset < this.regexlen) {

                    int low = this.regex.charAt(this.offset);

                    if (REUtil.isLowSurrogate(low)) {

                        this.chardata = REUtil.composeFromSurrogates(ch, low);

                        this.offset ++;

                    }

                }

                ret = T_CHAR;

            }

            this.nexttoken = ret;

            return;

        }

        switch (ch) {

          case '|': ret = T_OR;             break;

          case '*': ret = T_STAR;           break;

          case '+': ret = T_PLUS;           break;

          case '?': ret = T_QUESTION;       break;

          case ')': ret = T_RPAREN;         break;

          case '.': ret = T_DOT;            break;

          case '[': ret = T_LBRACKET;       break;

          case '^':

              if (this.isSet(RegularExpression.XMLSCHEMA_MODE)) {

                  ret = T_CHAR;

              }

              else {

                  ret = T_CARET;

              }

              break;

          case '$':

              if (this.isSet(RegularExpression.XMLSCHEMA_MODE)) {

                  ret = T_CHAR;

              }

              else {

                  ret = T_DOLLAR;

              }

              break;

          case '(':

            ret = T_LPAREN;

            if (this.offset >= this.regexlen)

                break;

            if (this.regex.charAt(this.offset) != '?')

                break;

            if (++this.offset >= this.regexlen)

                throw ex("parser.next.2", this.offset-1);

            ch = this.regex.charAt(this.offset++);

            switch (ch) {

              case ':':  ret = T_LPAREN2;            break;

              case '=':  ret = T_LOOKAHEAD;          break;

              case '!':  ret = T_NEGATIVELOOKAHEAD;  break;

              case '[':  ret = T_SET_OPERATIONS;     break;

              case '>':  ret = T_INDEPENDENT;        break;

              case '<':

                if (this.offset >= this.regexlen)

                    throw ex("parser.next.2", this.offset-3);

                ch = this.regex.charAt(this.offset++);

                if (ch == '=') {

                    ret = T_LOOKBEHIND;

                } else if (ch == '!') {

                    ret = T_NEGATIVELOOKBEHIND;

                } else

                    throw ex("parser.next.3", this.offset-3);

                break;

              case '#':

                while (this.offset < this.regexlen) {

                    ch = this.regex.charAt(this.offset++);

                    if (ch == ')')  break;

                }

                if (ch != ')')

                    throw ex("parser.next.4", this.offset-1);

                ret = T_COMMENT;

                break;

              default:

                if (ch == '-' || 'a' <= ch && ch <= 'z' || 'A' <= ch && ch <= 'Z') {// Options

                    this.offset --;

                    ret = T_MODIFIERS;

                    break;

                } else if (ch == '(') {         // conditional

                    ret = T_CONDITION;          // this.offsets points the next of '('.

                    break;

                }

                throw ex("parser.next.2", this.offset-2);

            }

            break;

          case '\\':

            ret = T_BACKSOLIDUS;

            if (this.offset >= this.regexlen)

                throw ex("parser.next.1", this.offset-1);

            this.chardata = this.regex.charAt(this.offset++);

            break;

          default:

            ret = T_CHAR;

        }

        this.nexttoken = ret;

    }

    /**

     * regex ::= term (`|` term)*

     * term ::= factor+

     * factor ::= ('^' | '$' | '\A' | '\Z' | '\z' | '\b' | '\B' | '\<' | '\>'

     *            | atom (('*' | '+' | '?' | minmax ) '?'? )?)

     *            | '(?=' regex ')'  | '(?!' regex ')'  | '(?<=' regex ')'  | '(?<!' regex ')'

     * atom ::= char | '.' | range | '(' regex ')' | '(?:' regex ')' | '\' [0-9]

     *          | '\w' | '\W' | '\d' | '\D' | '\s' | '\S' | category-block

     */

    Token parseRegex() throws ParseException {

        Token tok = this.parseTerm();

        Token parent = null;

        while (this.read() == T_OR) {

            this.next();                    // '|'

            if (parent == null) {

                parent = Token.createUnion();

                parent.addChild(tok);

                tok = parent;

            }

            tok.addChild(this.parseTerm());

        }

        return tok;

    }

    /**

     * term ::= factor+

     */

    Token parseTerm() throws ParseException {

        int ch = this.read();

        if (ch == T_OR || ch == T_RPAREN || ch == T_EOF) {

            return Token.createEmpty();

        } else {

            Token tok = this.parseFactor();

            Token concat = null;

            while ((ch = this.read()) != T_OR && ch != T_RPAREN && ch != T_EOF) {

                if (concat == null) {

                    concat = Token.createConcat();

                    concat.addChild(tok);

                    tok = concat;

                }

                concat.addChild(this.parseFactor());

                //tok = Token.createConcat(tok, this.parseFactor());

            }

            return tok;

        }

    }

    // ----------------------------------------------------------------

    Token processCaret() throws ParseException {

        this.next();

        return Token.token_linebeginning;

    }

    Token processDollar() throws ParseException {

        this.next();

        return Token.token_lineend;

    }

    Token processLookahead() throws ParseException {

        this.next();

        Token tok = Token.createLook(Token.LOOKAHEAD, this.parseRegex());

        if (this.read() != T_RPAREN)  throw ex("parser.factor.1", this.offset-1);

        this.next();                            // ')'

        return tok;

    }

    Token processNegativelookahead() throws ParseException {

        this.next();

        Token tok = Token.createLook(Token.NEGATIVELOOKAHEAD, this.parseRegex());

        if (this.read() != T_RPAREN)  throw ex("parser.factor.1", this.offset-1);

        this.next();                            // ')'

        return tok;

    }

    Token processLookbehind() throws ParseException {

        this.next();

        Token tok = Token.createLook(Token.LOOKBEHIND, this.parseRegex());

        if (this.read() != T_RPAREN)  throw ex("parser.factor.1", this.offset-1);

        this.next();                            // ')'

        return tok;

    }

    Token processNegativelookbehind() throws ParseException {

        this.next();

        Token tok = Token.createLook(Token.NEGATIVELOOKBEHIND, this.parseRegex());

        if (this.read() != T_RPAREN)  throw ex("parser.factor.1", this.offset-1);

        this.next();                    // ')'

        return tok;

    }

    Token processBacksolidus_A() throws ParseException {

        this.next();

        return Token.token_stringbeginning;

    }

    Token processBacksolidus_Z() throws ParseException {

        this.next();

        return Token.token_stringend2;

    }

    Token processBacksolidus_z() throws ParseException {

        this.next();

        return Token.token_stringend;

    }

    Token processBacksolidus_b() throws ParseException {

        this.next();

        return Token.token_wordedge;

    }

    Token processBacksolidus_B() throws ParseException {

        this.next();

        return Token.token_not_wordedge;

    }

    Token processBacksolidus_lt() throws ParseException {

        this.next();

        return Token.token_wordbeginning;

    }

    Token processBacksolidus_gt() throws ParseException {

        this.next();

        return Token.token_wordend;

    }

    Token processStar(Token tok) throws ParseException {

        this.next();

        if (this.read() == T_QUESTION) {

            this.next();

            return Token.createNGClosure(tok);

        } else

            return Token.createClosure(tok);

    }

    Token processPlus(Token tok) throws ParseException {

        // X+ -> XX*

        this.next();

        if (this.read() == T_QUESTION) {

            this.next();

            return Token.createConcat(tok, Token.createNGClosure(tok));

        } else

            return Token.createConcat(tok, Token.createClosure(tok));

    }

    Token processQuestion(Token tok) throws ParseException {

        // X? -> X|

        this.next();

        Token par = Token.createUnion();

        if (this.read() == T_QUESTION) {

            this.next();

            par.addChild(Token.createEmpty());

            par.addChild(tok);

        } else {

            par.addChild(tok);

            par.addChild(Token.createEmpty());

        }

        return par;

    }

    boolean checkQuestion(int off) {

        return off < this.regexlen && this.regex.charAt(off) == '?';

    }

    Token processParen() throws ParseException {

        this.next();

        int p = this.parenOpened++;

        Token tok = Token.createParen(this.parseRegex(), p);

        if (this.read() != T_RPAREN)  throw ex("parser.factor.1", this.offset-1);

        this.parennumber++;

        this.next();                            // Skips ')'

        return tok;

    }

    Token processParen2() throws ParseException {

        this.next();

        Token tok = Token.createParen(this.parseRegex(), 0);

        if (this.read() != T_RPAREN)  throw ex("parser.factor.1", this.offset-1);

        this.next();                            // Skips ')'

        return tok;

    }

    Token processCondition() throws ParseException {

                                                // this.offset points the next of '('

        if (this.offset+1 >= this.regexlen)  throw ex("parser.factor.4", this.offset);

                                                // Parses a condition.

        int refno = -1;

        Token condition = null;

        int ch = this.regex.charAt(this.offset);

        if ('1' <= ch && ch <= '9') {

            refno = ch-'0';

            int finalRefno = refno;

            if (this.parennumber <= refno)

                throw ex("parser.parse.2", this.offset);

            while (this.offset + 1 < this.regexlen) {

                ch = this.regex.charAt(this.offset + 1);

                if ('0' <= ch && ch <= '9') {

                    refno = (refno * 10) + (ch - '0');

                    if (refno < this.parennumber) {

                        finalRefno= refno;

                        ++this.offset;

                    }

                    else {

                        break;

                    }

                }

                else {

                    break;

                }

            }

            this.hasBackReferences = true;

            if (this.references == null)  this.references = new ArrayList<>();

            this.references.add(new ReferencePosition(finalRefno, this.offset));

            this.offset ++;

            if (this.regex.charAt(this.offset) != ')')  throw ex("parser.factor.1", this.offset);

            this.offset ++;

        } else {

            if (ch == '?')  this.offset --; // Points '('.

            this.next();

            condition = this.parseFactor();

            switch (condition.type) {

              case Token.LOOKAHEAD:

              case Token.NEGATIVELOOKAHEAD:

              case Token.LOOKBEHIND:

              case Token.NEGATIVELOOKBEHIND:

                break;

              case Token.ANCHOR:

                if (this.read() != T_RPAREN)  throw ex("parser.factor.1", this.offset-1);

                break;

              default:

                throw ex("parser.factor.5", this.offset);

            }

        }

                                                // Parses yes/no-patterns.

        this.next();

        Token yesPattern = this.parseRegex();

        Token noPattern = null;

        if (yesPattern.type == Token.UNION) {