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 * Copyright (c) 2013, 2017, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code 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 General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
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package com.oracle.svm.hosted.c.query;

import com.oracle.svm.hosted.c.info.PropertyInfo;

public class QueryParserUtil {

    // The size of hex string the represents a long integer
    static final int SIZE_OF_LONG_HEX = 16;

    static void parseSigned(PropertyInfo<Object> info, String hex) {
        if (isNegative(hex)) {
            if (hex.length() < SIZE_OF_LONG_HEX) {
                String extended = signedExtend(hex);
                parseHexToLong(info, extended);
            } else {
                parseHexToLong(info, hex);
            }
        } else {
            parseHexToLong(info, hex);
        }
    }

    
Only checks the most significant digit in the hexadecimal representation of the integer
number. This method converts the most significant digit from String to int and check if its
value if greater or equals to 8, if it is the most significant bit is set. Therefore, the
integer number is negative.

A unsigned integer should not use this method.
Params:
hex – hexadecimal string representation of the integer being checked
Returns:
true if the hex represents a negative signed integer; no if it does not/**
     * Only checks the most significant digit in the hexadecimal representation of the integer
     * number. This method converts the most significant digit from String to int and check if its
     * value if greater or equals to 8, if it is the most significant bit is set. Therefore, the
     * integer number is negative.
     * <p>
     * A unsigned integer should not use this method.
     *
     * @param hex hexadecimal string representation of the integer being checked
     * @return true if the hex represents a negative signed integer; no if it does not
     */
    static boolean isNegative(String hex) {
        int mostSignificantDigit = Integer.parseInt(hex.substring(0, 1), 16);

        if (mostSignificantDigit >= 8) {
            return true;
        }

        return false;
    }

    static String unsignedExtend(String hex) {
        int numOfMissingHexDigit = SIZE_OF_LONG_HEX - hex.length();
        StringBuilder sb = new StringBuilder();

        for (int i = 0; i < numOfMissingHexDigit; i++) {
            sb.append('0');
        }

        return sb.append(hex).toString();
    }

    static String unsignedExtendToSize(int sizeInByte, String hex) {
        int numOfMissingHexDigit = sizeInByte * 2 - hex.length();
        StringBuilder sb = new StringBuilder();

        for (int i = 0; i < numOfMissingHexDigit; i++) {
            sb.append('0');
        }

        return sb.append(hex).toString();
    }

    static String signedExtend(String hex) {
        int numOfMissingHexDigit = SIZE_OF_LONG_HEX - hex.length();
        StringBuilder sb = new StringBuilder();

        for (int i = 0; i < numOfMissingHexDigit; i++) {
            sb.append('F');
        }

        return sb.append(hex).toString();
    }

    
Extends short or int hex to long hex by assigning most significant bits to 0, and then parses
the hex string in chunks to avoid the problem that { Long.parseLong } does not deal with
two's complement.

Signed negative hex should already be signed extended before calling { parseHexToLong }.
Params:
info – ValueInfo to be updated
hex – Hex string to be parsed/**
     * Extends short or int hex to long hex by assigning most significant bits to 0, and then parses
     * the hex string in chunks to avoid the problem that { Long.parseLong } does not deal with
     * two's complement.
     * <p>
     * Signed negative hex should already be signed extended before calling { parseHexToLong }.
     *
     * @param info ValueInfo to be updated
     * @param hex Hex string to be parsed
     */
    static void parseHexToLong(PropertyInfo<Object> info, String hex) {
        String extended = unsignedExtend(hex);

        try {
            String msb = extended.substring(0, 8);
            String lsb = extended.substring(8);
            long msbValue = Long.parseLong(msb, 16);
            long lsbValue = Long.parseLong(lsb, 16);
            long value = msbValue << 32 | lsbValue;
            info.setProperty(value);
        } catch (NumberFormatException e) {
            parseHexToLongUnsafe(info, hex);
        }
    }

    static void parseHexToLongUnsafe(PropertyInfo<Object> info, String hex) {
        long value = 0;

        for (int i = 0; i < hex.length(); i++) {
            char digit = hex.charAt(i);
            value = 16 * value + Character.getNumericValue(digit);
        }

        info.setProperty(value);
    }

}