add reconstructBigramFrequency

Change-Id: Iff20dcb9ca0d6064bb118247887fe24b812c0c61

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

@@ -52,14 +52,14 @@ public class UserHistoryDictionary extends ExpandableDictionary {
     private static final int FREQUENCY_FOR_TYPED = 2;
 
     /** Maximum number of pairs. Pruning will start when databases goes above this number. */
-    private static int sMaxHistoryBigrams = 10000;
+    public static final int sMaxHistoryBigrams = 10000;
 
     /**
      * When it hits maximum bigram pair, it will delete until you are left with
      * only (sMaxHistoryBigrams - sDeleteHistoryBigrams) pairs.
      * Do not keep this number small to avoid deleting too often.
      */
-    private static int sDeleteHistoryBigrams = 1000;
+    public static final int sDeleteHistoryBigrams = 1000;
 
     /**
      * Database version should increase if the database structure changes
@@ -109,12 +109,8 @@ public class UserHistoryDictionary extends ExpandableDictionary {
 
     private static DatabaseHelper sOpenHelper = null;
 
-    public void setDatabaseMax(int maxHistoryBigram) {
+    public String getLocale() {
-        sMaxHistoryBigrams = maxHistoryBigram;
+        return mLocale;
-    }
-
-    public void setDatabaseDelete(int deleteHistoryBigram) {
-        sDeleteHistoryBigrams = deleteHistoryBigram;
     }
 
     public synchronized static UserHistoryDictionary getInstance(
@@ -502,9 +498,11 @@ public class UserHistoryDictionary extends ExpandableDictionary {
                                     needsToSave(fc, isValid, addLevel0Bigram)) {
                                 freq = fc;
                             } else {
+                                // Delete this entry
                                 freq = -1;
                             }
                         } else {
+                            // Delete this entry
                             freq = -1;
                         }
                     }
@@ -541,6 +539,7 @@ public class UserHistoryDictionary extends ExpandableDictionary {
                                     getContentValues(word1, word2, mLocale));
                             pairId = pairIdLong.intValue();
                         }
+                        // Eliminate freq == 0 because that word is profanity.
                         if (freq > 0) {
                             if (PROFILE_SAVE_RESTORE) {
                                 ++profInsert;

java/src/com/android/inputmethod/latin/makedict/BinaryDictInputOutput.java

@@ -1410,4 +1410,22 @@ public class BinaryDictInputOutput {
             return false;
         }
     }
+
+    /**
+     * Calculate bigram frequency from compressed value
+     *
+     * @see #makeBigramFlags
+     *
+     * @param unigramFrequency
+     * @param bigramFrequency compressed frequency
+     * @return approximate bigram frequency
+     */
+    public static int reconstructBigramFrequency(final int unigramFrequency,
+            final int bigramFrequency) {
+        final float stepSize = (MAX_TERMINAL_FREQUENCY - unigramFrequency)
+                / (1.5f + MAX_BIGRAM_FREQUENCY);
+        final float resultFreqFloat = (float)unigramFrequency
+                + stepSize * (bigramFrequency + 1.0f);
+        return (int)resultFreqFloat;
+    }
 }