Activate bigram predictions from the binary dictionary

Change-Id: If1cc50539d7677b854b1cd3bea3423c8c0865de5

java/src/com/android/inputmethod/latin/BinaryDictionary.java

@@ -139,22 +139,19 @@ public class BinaryDictionary extends Dictionary {
         Arrays.fill(mBigramScores, 0);
 
         int codesSize = codes.size();
-        if (codesSize <= 0) {
-            // Do not return bigrams from BinaryDictionary when nothing was typed.
-            // Only use user-history bigrams (or whatever other bigram dictionaries decide).
-            return;
-        }
         Arrays.fill(mInputCodes, -1);
-        int[] alternatives = codes.getCodesAt(0);
-        System.arraycopy(alternatives, 0, mInputCodes, 0,
-                Math.min(alternatives.length, MAX_PROXIMITY_CHARS_SIZE));
+        if (codesSize > 0) {
+            int[] alternatives = codes.getCodesAt(0);
+            System.arraycopy(alternatives, 0, mInputCodes, 0,
+                    Math.min(alternatives.length, MAX_PROXIMITY_CHARS_SIZE));
+        }
 
         int count = getBigramsNative(mNativeDict, chars, chars.length, mInputCodes, codesSize,
                 mOutputChars_bigrams, mBigramScores, MAX_WORD_LENGTH, MAX_BIGRAMS,
                 MAX_PROXIMITY_CHARS_SIZE);
 
         for (int j = 0; j < count; ++j) {
-            if (mBigramScores[j] < 1) break;
+            if (codesSize > 0 && mBigramScores[j] < 1) break;
             final int start = j * MAX_WORD_LENGTH;
             int len = 0;
             while (len <  MAX_WORD_LENGTH && mOutputChars_bigrams[start + len] != 0) {

native/src/bigram_dictionary.cpp

@@ -134,7 +134,8 @@ int BigramDictionary::getBigrams(unsigned short *prevWord, int prevWordLength, i
         const int length = BinaryFormat::getWordAtAddress(root, bigramPos, MAX_WORD_LENGTH,
                 bigramBuffer);
 
-        if (checkFirstCharacter(bigramBuffer)) {
+        // codesSize == 0 means we are trying to find bigram predictions.
+        if (codesSize < 1 || checkFirstCharacter(bigramBuffer)) {
             const int frequency = UnigramDictionary::MASK_ATTRIBUTE_FREQUENCY & bigramFlags;
             addWordBigram(bigramBuffer, length, frequency);
         }