001/*
002 * VM-Operator
003 * Copyright (C) 2023 Michael N. Lipp
004 * 
005 * This program is free software: you can redistribute it and/or modify
006 * it under the terms of the GNU Affero General Public License as
007 * published by the Free Software Foundation, either version 3 of the
008 * License, or (at your option) any later version.
009 *
010 * This program is distributed in the hope that it will be useful,
011 * but WITHOUT ANY WARRANTY; without even the implied warranty of
012 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
013 * GNU Affero General Public License for more details.
014 *
015 * You should have received a copy of the GNU Affero General Public License
016 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
017 */
018
019package org.jdrupes.vmoperator.common;
020
021import java.math.BigDecimal;
022import java.math.BigInteger;
023import java.util.HashMap;
024import java.util.List;
025import java.util.Map;
026import java.util.regex.Pattern;
027
028/**
029 * Provides methods for parsing "official" memory sizes..
030 */
031@SuppressWarnings("PMD.UseUtilityClass")
032public class Convertions {
033
034    @SuppressWarnings({ "PMD.UseConcurrentHashMap",
035        "PMD.FieldNamingConventions" })
036    private static final Map<String, BigInteger> unitMap = new HashMap<>();
037    @SuppressWarnings({ "PMD.FieldNamingConventions" })
038    private static final List<Map.Entry<String, BigInteger>> unitMappings;
039    @SuppressWarnings({ "PMD.FieldNamingConventions" })
040    private static final Pattern memorySize
041        = Pattern.compile("^\\s*(\\d+(\\.\\d+)?)\\s*([A-Za-z]*)\\s*");
042
043    static {
044        // SI units and common abbreviations
045        BigInteger factor = BigInteger.ONE;
046        unitMap.put("", factor);
047        BigInteger scale = BigInteger.valueOf(1000);
048        for (var unit : List.of("B", "kB", "MB", "GB", "TB", "PB", "EB")) {
049            unitMap.put(unit, factor);
050            factor = factor.multiply(scale);
051        }
052        // Binary units
053        factor = BigInteger.valueOf(1024);
054        scale = BigInteger.valueOf(1024);
055        for (var unit : List.of("KiB", "MiB", "GiB", "TiB", "PiB", "EiB")) {
056            unitMap.put(unit, factor);
057            factor = factor.multiply(scale);
058        }
059        unitMappings = unitMap.entrySet().stream()
060            .sorted((a, b) -> -1 * a.getValue().compareTo(b.getValue()))
061            .toList();
062    }
063
064    /**
065     * Parses a memory size specification.
066     *
067     * @param amount the amount
068     * @return the big integer
069     */
070    public static BigInteger parseMemory(Object amount) {
071        if (amount == null) {
072            return (BigInteger) amount;
073        }
074        if (amount instanceof BigInteger number) {
075            return number;
076        }
077        if (amount instanceof Number number) {
078            return BigInteger.valueOf(number.longValue());
079        }
080        var matcher = memorySize.matcher(amount.toString());
081        if (!matcher.matches()) {
082            throw new NumberFormatException(amount.toString());
083        }
084        var unit = BigInteger.ONE;
085        if (matcher.group(3) != null) {
086            unit = unitMap.get(matcher.group(3));
087            if (unit == null) {
088                throw new NumberFormatException("Illegal unit \""
089                    + matcher.group(3) + "\" in \"" + amount.toString() + "\"");
090            }
091        }
092        var number = matcher.group(1);
093        return new BigDecimal(number).multiply(new BigDecimal(unit))
094            .toBigInteger();
095    }
096
097    /**
098     * Format memory size for humans.
099     *
100     * @param size the size
101     * @return the string
102     */
103    public static String formatMemory(BigInteger size) {
104        for (var mapping : unitMappings) {
105            if (size.compareTo(mapping.getValue()) >= 0
106                && size.mod(mapping.getValue()).equals(BigInteger.ZERO)) {
107                return (size.divide(mapping.getValue()).toString()
108                    + " " + mapping.getKey()).trim();
109            }
110        }
111        return size.toString();
112    }
113}