Add EmojiManager#extractEmojisInOrderWithIndex

lib/src/main/java/net/fellbaum/jemoji/EmojiManager.java

@@ -15,10 +15,7 @@
 import java.util.stream.Collector;
 import java.util.stream.Collectors;
 
-import static net.fellbaum.jemoji.EmojiUtils.addColonToAlias;
-import static net.fellbaum.jemoji.EmojiUtils.findEmojiByEitherAlias;
-import static net.fellbaum.jemoji.EmojiUtils.isStringNullOrEmpty;
-import static net.fellbaum.jemoji.EmojiUtils.removeColonFromAlias;
+import static net.fellbaum.jemoji.EmojiUtils.*;
 
 @SuppressWarnings("unused")
 public final class EmojiManager {
@@ -308,6 +305,56 @@ public static List<Emoji> extractEmojisInOrder(final String text) {
         return Collections.unmodifiableList(emojis);
     }
 
+    /**
+     * Extracts all emojis from the given text in the order they appear.
+     *
+     * @param text The text to extract emojis from.
+     * @return A list of indexed emojis.
+     */
+    public static List<IndexedEmoji> extractEmojisInOrderWithIndex(final String text) {
+        if (isStringNullOrEmpty(text)) return Collections.emptyList();
+
+        final List<IndexedEmoji> emojis = new ArrayList<>();
+
+        final int[] textCodePointsArray = text.codePoints().toArray();
+        final long textCodePointsLength = textCodePointsArray.length;
+
+        int charIndex = 0;
+        nextTextIteration:
+        for (int textIndex = 0; textIndex < textCodePointsLength; textIndex++) {
+            final int currentCodepoint = textCodePointsArray[textIndex];
+            final List<Emoji> emojisByCodePoint = EMOJI_FIRST_CODEPOINT_TO_EMOJIS_ORDER_CODEPOINT_LENGTH_DESCENDING.get(currentCodepoint);
+            if (emojisByCodePoint == null) {
+                charIndex += Character.charCount(currentCodepoint);
+                continue;
+            }
+            for (final Emoji emoji : emojisByCodePoint) {
+                final int[] emojiCodePointsArray = emoji.getEmoji().codePoints().toArray();
+                final int emojiCodePointsLength = emojiCodePointsArray.length;
+                // Emoji code points are in bounds of the text code points
+                if (!((textIndex + emojiCodePointsLength) <= textCodePointsLength)) {
+                    continue;
+                }
+
+                for (int emojiCodePointIndex = 0; emojiCodePointIndex < emojiCodePointsLength; emojiCodePointIndex++) {
+                    if (textCodePointsArray[textIndex + emojiCodePointIndex] != emojiCodePointsArray[emojiCodePointIndex]) {
+                        break;
+                    }
+                    if (emojiCodePointIndex == (emojiCodePointsLength - 1)) {
+                        emojis.add(new IndexedEmoji(emoji, charIndex, textIndex));
+                        textIndex += emojiCodePointsLength - 1;
+                        charIndex += emoji.getEmoji().length();
+                        continue nextTextIteration;
+                    }
+                }
+            }
+
+            charIndex += Character.charCount(currentCodepoint);
+        }
+
+        return Collections.unmodifiableList(emojis);
+    }
+
     /**
      * Extracts all emojis from the given text.
      *

lib/src/main/java/net/fellbaum/jemoji/IndexedEmoji.java

@@ -0,0 +1,51 @@
+package net.fellbaum.jemoji;
+
+/**
+ * Represents an emoji with character and codepoint indexes.
+ *
+ * @see EmojiManager#extractEmojisInOrderWithIndex(String)
+ */
+public class IndexedEmoji {
+    private final Emoji emoji;
+    private final int charIndex;
+    private final int codePointIndex;
+
+    IndexedEmoji(Emoji emoji, int charIndex, int codePointIndex) {
+        this.emoji = emoji;
+        this.charIndex = charIndex;
+        this.codePointIndex = codePointIndex;
+    }
+
+    /**
+     * Gets the captured {@link Emoji emoji}.
+     *
+     * @return The captured emoji
+     */
+    public Emoji getEmoji() {
+        return emoji;
+    }
+
+    /**
+     * Gets the character index at which the emoji starts.
+     *
+     * <p>The index is included in {@code 0 < input <= input.length() - 1}
+     *
+     * @return The character index at which the emoji starts
+     */
+    public int getCharIndex() {
+        return charIndex;
+    }
+
+    /**
+     * Gets the codepoint index at which the emoji starts.
+     *
+     * <p>This must not be confused with {@link #getCharIndex()},
+     * a codepoint can contain one or two characters,
+     * which means the codepoint index will likely be lower than the character index.
+     *
+     * @return The character index at which the emoji starts
+     */
+    public int getCodePointIndex() {
+        return codePointIndex;
+    }
+}

lib/src/test/java/net/fellbaum/jemoji/EmojiManagerTest.java

@@ -8,14 +8,13 @@
 import java.util.Set;
 import java.util.stream.Collectors;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.*;
 
 public class EmojiManagerTest {
 
     public static final String ALL_EMOJIS_STRING = EmojiManager.getAllEmojisLengthDescending().stream().map(Emoji::getEmoji).collect(Collectors.joining());
     private static final String SIMPLE_EMOJI_STRING = "Hello ❤️ ❤ ❤❤️ World";
+    private static final String SIMPLE_POSITION_EMOJI_STRING = "Hello ❤️ ❤ 👩🏻‍🤝‍👨🏼 ❤❤️ World";
 
     @Test
     public void extractEmojisInOrder() {
@@ -28,6 +27,37 @@ public void extractEmojisInOrder() {
         assertEquals(allEmojis, emojis);
     }
 
+    @Test
+    public void extractEmojisInOrderWithIndex() {
+        List<Emoji> emojis = EmojiManager.extractEmojisInOrderWithIndex(ALL_EMOJIS_STRING + ALL_EMOJIS_STRING)
+                .stream()
+                .map(IndexedEmoji::getEmoji)
+                .collect(Collectors.toList());
+
+        assertEquals(EmojiManager.getAllEmojisLengthDescending().size() * 2, emojis.size());
+        List<Emoji> allEmojis = new ArrayList<>(EmojiManager.getAllEmojisLengthDescending());
+        allEmojis.addAll(EmojiManager.getAllEmojisLengthDescending());
+
+        assertEquals(allEmojis, emojis);
+    }
+
+    @Test
+    public void extractEmojisInOrderWithIndexCheckPosition() {
+        List<IndexedEmoji> emojis = EmojiManager.extractEmojisInOrderWithIndex(SIMPLE_POSITION_EMOJI_STRING);
+        assertEquals(5, emojis.size());
+
+        checkIndexedEmoji(emojis.get(0), 6, 6);
+        checkIndexedEmoji(emojis.get(1), 9, 9);
+        checkIndexedEmoji(emojis.get(2), 11, 11);
+        checkIndexedEmoji(emojis.get(3), 24, 19);
+        checkIndexedEmoji(emojis.get(4), 25, 20);
+    }
+
+    private void checkIndexedEmoji(IndexedEmoji indexedEmoji, int expectedCharIndex, int expectedCodePointIndex) {
+        assertEquals(expectedCharIndex, indexedEmoji.getCharIndex());
+        assertEquals(expectedCodePointIndex, indexedEmoji.getCodePointIndex());
+    }
+
     @Test
     public void extractEmojis() {
         Set<Emoji> emojis = EmojiManager.extractEmojis(ALL_EMOJIS_STRING + ALL_EMOJIS_STRING);