com.itextpdf.styledxmlparser.css.parse.CssDeclarationValueTokenizer Maven / Gradle / Ivy

/*
    This file is part of the iText (R) project.
    Copyright (c) 1998-2023 Apryse Group NV
    Authors: Apryse Software.

    This program is offered under a commercial and under the AGPL license.
    For commercial licensing, contact us at https://itextpdf.com/sales.  For AGPL licensing, see below.

    AGPL licensing:
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU Affero General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program 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 Affero General Public License for more details.

    You should have received a copy of the GNU Affero General Public License
    along with this program.  If not, see .
 */
package com.itextpdf.styledxmlparser.css.parse;

/**
 * Tokenizer for CSS declaration values.
 */
public class CssDeclarationValueTokenizer {
    
    /** The source string. */
    private String src;
    
    /** The current index. */
    private int index = -1;
    
    /** The quote string, either "'" or "\"". */
    private char stringQuote;
    
    /** Indicates if we're inside a string. */
    private boolean inString;
    
    /** The depth. */
    private int functionDepth = 0;

    /**
     * Creates a new {@link CssDeclarationValueTokenizer} instance.
     *
     * @param propertyValue the property value
     */
    public CssDeclarationValueTokenizer(String propertyValue) {
        this.src = propertyValue;
    }

    /**
     * Gets the next valid token.
     *
     * @return the next valid token
     */
    public Token getNextValidToken() {
        Token token = getNextToken();
        while (token != null && !token.isString() && token.getValue().trim().isEmpty()) {
            token = getNextToken();
        }
        if (token != null && functionDepth > 0) {
            StringBuilder functionBuffer = new StringBuilder();
            while (token != null && functionDepth > 0) {
                processFunctionToken(token, functionBuffer);
                token = getNextToken();
            }
            functionDepth = 0;
            if (functionBuffer.length() != 0) {
                if (token != null) {
                    processFunctionToken(token, functionBuffer);
                }
                return new Token(functionBuffer.toString(), TokenType.FUNCTION);
            }
        }
        return token;
    }

    /**
     * Gets the next token.
     *
     * @return the next token
     */
    private Token getNextToken() {
        StringBuilder buff = new StringBuilder();
        char curChar;
        if (index >= src.length() - 1) {
            return null;
        }
        if (inString) {
            boolean isEscaped = false;
            StringBuilder pendingUnicodeSequence = new StringBuilder();
            while (++index < src.length()) {
                curChar = src.charAt(index);
                if (isEscaped) {
                    if (isHexDigit(curChar) && pendingUnicodeSequence.length() < 6) {
                        pendingUnicodeSequence.append(curChar);
                    } else if (pendingUnicodeSequence.length() != 0) {
                        int codePoint = Integer.parseInt(pendingUnicodeSequence.toString(), 16);
                        if (Character.isValidCodePoint(codePoint)) {
                            buff.appendCodePoint(codePoint);
                        } else {
                            buff.append("\uFFFD");
                        }
                        pendingUnicodeSequence.setLength(0);
                        if (curChar == stringQuote) {
                            inString = false;
                            return new Token(buff.toString(), TokenType.STRING);
                        } else if (!Character.isWhitespace(curChar)) {
                            buff.append(curChar);
                        }
                        isEscaped = false;
                    } else {
                        buff.append(curChar);
                        isEscaped = false;
                    }
                } else if (curChar == stringQuote){
                    inString = false;
                    return new Token(buff.toString(), TokenType.STRING);
                } else if (curChar == '\\') {
                    isEscaped = true;
                } else {
                    buff.append(curChar);
                }
            }
        } else {
            while (++index < src.length()) {
                curChar = src.charAt(index);
                if (curChar == '(') {
                    ++functionDepth;
                    buff.append(curChar);
                } else if (curChar == ')') {
                    --functionDepth;
                    buff.append(curChar);
                    if (functionDepth == 0) {
                        return new Token(buff.toString(), TokenType.FUNCTION);
                    }
                } else if (curChar == '"' || curChar == '\'') {
                    stringQuote = curChar;
                    inString = true;
                    return new Token(buff.toString(), TokenType.FUNCTION);
                } else if (curChar == ',' && !inString && functionDepth == 0) {
                    if (buff.length() == 0) {
                        return new Token(",", TokenType.COMMA);
                    } else {
                        --index;
                        return new Token(buff.toString(), TokenType.UNKNOWN);
                    }
                } else if (Character.isWhitespace(curChar)) {
                    if (functionDepth > 0) {
                        buff.append(curChar);
                    }
                    return new Token(buff.toString(), functionDepth > 0 ? TokenType.FUNCTION : TokenType.UNKNOWN);
                } else {
                    buff.append(curChar);
                }
            }
        }
        return new Token(buff.toString(), TokenType.FUNCTION);
    }

    /**
     * Checks if a character is a hexadecimal digit.
     *
     * @param c the character
     * @return true, if it's a hexadecimal digit
     */
    private boolean isHexDigit(char c) {
        return (47 < c && c < 58) || (64 < c && c < 71) || (96 < c && c < 103);
    }

    /**
     * Processes a function token.
     *
     * @param token the token
     * @param functionBuffer the function buffer
     */
    private void processFunctionToken(Token token, StringBuilder functionBuffer) {
        if (token.isString()) {
            functionBuffer.append(stringQuote);
            functionBuffer.append(token.getValue());
            functionBuffer.append(stringQuote);
        } else {
            functionBuffer.append(token.getValue());
        }
    }

    /**
     * The Token class.
     */
    public static class Token {
        
        /** The value. */
        private String value;
        
        /** The type. */
        private TokenType type;

        /**
         * Creates a new {@link Token} instance.
         *
         * @param value the value
         * @param type the type
         */
        public Token(String value, TokenType type) {
            this.value = value;
            this.type = type;
        }

        /**
         * Gets the value.
         *
         * @return the value
         */
        public String getValue() {
            return value;
        }

        /**
         * Gets the type.
         *
         * @return the type
         */
        public TokenType getType() {
            return type;
        }

        /**
         * Checks if the token is a string.
         *
         * @return true, if is string
         */
        public boolean isString() {
            return type == TokenType.STRING;
        }

        /* (non-Javadoc)
         * @see java.lang.Object#toString()
         */
        @Override
        public String toString() {
            return value;
        }
    }

    /**
     * Enumeration of the different token types.
     */
    public enum TokenType {
        
        /** The string type. */
        STRING,
        
        /** The function type. */
        FUNCTION,
        
        /** The comma type. */
        COMMA,
        
        /** Unknown type. */
        UNKNOWN
    }
}