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 * Copyright (c) 2019, 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.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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package build.tools.generateemojidata;

import java.io.IOException;

import java.nio.file.Files;

import java.nio.file.Paths;

import java.nio.file.StandardOpenOption;

import java.util.ArrayList;

import java.util.List;

import java.util.function.Predicate;

import java.util.stream.Collectors;

import java.util.stream.Stream;

/**

 * Generate EmojiData.java

 *    args[0]: Full path string to the template file

 *    args[1]: Full path string to the directory that contains "emoji-data.txt"

 *    args[2]: Full path string to the generated .java file

 */

public class GenerateEmojiData {

    public static void main(String[] args) {

        try {

            final Range[] last = new Range[1]; // last extended pictographic range

            last[0] = new Range(0, 0);

            List<Range> extPictRanges = Files.lines(Paths.get(args[1], "emoji-data.txt"))

                .filter(Predicate.not(l -> l.startsWith("#") || l.isBlank()))

                .filter(l -> l.contains("; Extended_Pictograph"))

                .map(l -> new Range(l.replaceFirst(" .*", "")))

                .sorted()

                .collect(ArrayList<Range>::new,

                    (list, r) -> {

                        // collapsing consecutive pictographic ranges

                        int lastIndex = list.size() - 1;

                        if (lastIndex >= 0) {

                            Range lastRange = list.get(lastIndex);

                            if (lastRange.last + 1 == r.start) {

                                list.set(lastIndex, new Range(lastRange.start, r.last));

                                return;

                            }

                        }

                        list.add(r);

                    },

                    ArrayList<Range>::addAll);

            // make the code point conditions

            // only very few codepoints below 0x2000 are "emojis", so separate them

            // out to generate a fast-path check that can be efficiently inlined

            String lowExtPictCodePoints = extPictRanges.stream()

                    .takeWhile(r -> r.last < 0x2000)

                    .map(r -> rangeToString(r))

                    .collect(Collectors.joining(" ||\n", "", ";\n"));

            String highExtPictCodePoints = extPictRanges.stream()

                    .dropWhile(r -> r.last < 0x2000)

                    .map(r -> rangeToString(r))

                    .collect(Collectors.joining(" ||\n", "", ";\n"));

            // Generate EmojiData.java file

            Files.write(Paths.get(args[2]),

                Files.lines(Paths.get(args[0]))

                    .flatMap(l -> {

                        if (l.equals("%%%EXTPICT_LOW%%%")) {

                            return Stream.of(lowExtPictCodePoints);

                        } else if (l.equals("%%%EXTPICT_HIGH%%%")) {

                            return Stream.of(highExtPictCodePoints);

                        } else {

                            return Stream.of(l);

                        }

                    })

                    .collect(Collectors.toList()),

                StandardOpenOption.CREATE, StandardOpenOption.TRUNCATE_EXISTING);

        } catch (IOException e) {

            e.printStackTrace();

        }

    }

    static String rangeToString(Range r) {

        if (r.start == r.last) {

            return (" ".repeat(16) + "cp == 0x" + toHexString(r.start));

        } else  if (r.start == r.last - 1) {

            return " ".repeat(16) + "cp == 0x" + toHexString(r.start) + " ||\n" +

                    " ".repeat(16) + "cp == 0x" + toHexString(r.last);

        } else {

            return " ".repeat(15) + "(cp >= 0x" + toHexString(r.start) +

                    " && cp <= 0x" + toHexString(r.last) + ")";

        }

    }

    static int toInt(String hexStr) {

        return Integer.parseUnsignedInt(hexStr, 16);

    }

    static String toHexString(int cp) {

        String ret = Integer.toUnsignedString(cp, 16).toUpperCase();

        if (ret.length() < 4) {

            ret = "0".repeat(4 - ret.length()) + ret;

        }

        return ret;

    }

    static class Range implements Comparable<Range> {

        int start;

        int last;

        Range (int start, int last) {

            this.start = start;

            this.last = last;

        }

        Range (String input) {

            input = input.replaceFirst("\\s#.*", "");

            start = toInt(input.replaceFirst("[\\s\\.].*", ""));

            last = input.contains("..") ?

                    toInt(input.replaceFirst(".*\\.\\.", "")

                            .replaceFirst(";.*", "").trim())

                    : start;

        }

        @Override

        public String toString() {

            return "Start: " + toHexString(start) + ", Last: " + toHexString(last);

        }

        @Override

        public int compareTo(Range other) {

            return Integer.compare(start, other.start);

        }

    }

}