Fix two nasty bugs with surrogate pairs.

The important bug is in findWordInTree. The problem, which is
not obvious, is that we were calling codePointAt() with the
code point index in the string, instead of the char index.
The other bug this change fixes was harmless in the practice,
because it's in the iteration which is only used for debug and
pretty printing purposes. It's very similar in that it would
substract a length in code point to a length in chars and
truncate a StringBuilder at that length, so it would fail in a
quite similar manner. This changes the meaning of the "length"
attribute in Position, but it's clearer this way anyway.

Bug: 8450145
Change-Id: If396f883a9e6449de39351553ba83f5be5bd30f0

1 files changed, 13 insertions, 13 deletions

diff --git a/java/src/com/android/inputmethod/latin/makedict/FusionDictionary.java b/java/src/com/android/inputmethod/latin/makedict/FusionDictionary.java
index 5c805598a..e7c7e2b8a 100644
--- a/java/src/com/android/inputmethod/latin/makedict/FusionDictionary.java
+++ b/java/src/com/android/inputmethod/latin/makedict/FusionDictionary.java
@@ -620,34 +620,34 @@ public final class FusionDictionary implements Iterable<Word> {
      * Helper method to find a word in a given branch.
      */
     @SuppressWarnings("unused")
-    public static CharGroup findWordInTree(Node node, final String s) {
+    public static CharGroup findWordInTree(Node node, final String string) {
         int index = 0;
         final StringBuilder checker = DBG ? new StringBuilder() : null;
+        final int[] codePoints = getCodePoints(string);
 
         CharGroup currentGroup;
-        final int codePointCountInS = s.codePointCount(0, s.length());
         do {
-            int indexOfGroup = findIndexOfChar(node, s.codePointAt(index));
+            int indexOfGroup = findIndexOfChar(node, codePoints[index]);
             if (CHARACTER_NOT_FOUND == indexOfGroup) return null;
             currentGroup = node.mData.get(indexOfGroup);
 
-            if (s.length() - index < currentGroup.mChars.length) return null;
+            if (codePoints.length - index < currentGroup.mChars.length) return null;
             int newIndex = index;
-            while (newIndex < s.length() && newIndex - index < currentGroup.mChars.length) {
-                if (currentGroup.mChars[newIndex - index] != s.codePointAt(newIndex)) return null;
+            while (newIndex < codePoints.length && newIndex - index < currentGroup.mChars.length) {
+                if (currentGroup.mChars[newIndex - index] != codePoints[newIndex]) return null;
                 newIndex++;
             }
             index = newIndex;
 
             if (DBG) checker.append(new String(currentGroup.mChars, 0, currentGroup.mChars.length));
-            if (index < codePointCountInS) {
+            if (index < codePoints.length) {
                 node = currentGroup.mChildren;
             }
-        } while (null != node && index < codePointCountInS);
+        } while (null != node && index < codePoints.length);
 
-        if (index < codePointCountInS) return null;
+        if (index < codePoints.length) return null;
         if (!currentGroup.isTerminal()) return null;
-        if (DBG && !s.equals(checker.toString())) return null;
+        if (DBG && !codePoints.equals(checker.toString())) return null;
         return currentGroup;
     }
 
@@ -847,12 +847,12 @@ public final class FusionDictionary implements Iterable<Word> {
         @Override
         public Word next() {
             Position currentPos = mPositions.getLast();
-            mCurrentString.setLength(mCurrentString.length() - currentPos.length);
+            mCurrentString.setLength(currentPos.length);
 
             do {
                 if (currentPos.pos.hasNext()) {
                     final CharGroup currentGroup = currentPos.pos.next();
-                    currentPos.length = currentGroup.mChars.length;
+                    currentPos.length = mCurrentString.length();
                     for (int i : currentGroup.mChars)
                         mCurrentString.append(Character.toChars(i));
                     if (null != currentGroup.mChildren) {
@@ -866,7 +866,7 @@ public final class FusionDictionary implements Iterable<Word> {
                 } else {
                     mPositions.removeLast();
                     currentPos = mPositions.getLast();
-                    mCurrentString.setLength(mCurrentString.length() - mPositions.getLast().length);
+                    mCurrentString.setLength(mPositions.getLast().length);
                 }
             } while (true);
         }