Fix parameters of native functions and refactor Dictionary

- created bigram/unigram dictionary classes

Change-Id: I233a28ed8d611870db3f4cf8f25fc45b5d41529b

8 files changed, 840 insertions, 668 deletions

diff --git a/native/Android.mk b/native/Android.mk
index 97051c92f..bbbff1efe 100644
--- a/native/Android.mk
+++ b/native/Android.mk
@@ -4,9 +4,11 @@ include $(CLEAR_VARS)
 LOCAL_C_INCLUDES += $(LOCAL_PATH)/src
 
 LOCAL_SRC_FILES := \
-	jni/com_android_inputmethod_latin_BinaryDictionary.cpp \
-	src/dictionary.cpp \
-	src/char_utils.cpp
+    jni/com_android_inputmethod_latin_BinaryDictionary.cpp \
+    src/bigram_dictionary.cpp \
+    src/char_utils.cpp \
+    src/dictionary.cpp \
+    src/unigram_dictionary.cpp
 
 #FLAG_DBG := true
 
diff --git a/native/jni/com_android_inputmethod_latin_BinaryDictionary.cpp b/native/jni/com_android_inputmethod_latin_BinaryDictionary.cpp
index bf7ec0d1a..6ed743c2e 100644
--- a/native/jni/com_android_inputmethod_latin_BinaryDictionary.cpp
+++ b/native/jni/com_android_inputmethod_latin_BinaryDictionary.cpp
@@ -42,21 +42,23 @@ static void throwException(JNIEnv *env, const char* ex, const char* fmt, int dat
 
 static jint latinime_BinaryDictionary_open
         (JNIEnv *env, jobject object, jobject dictDirectBuffer,
-         jint typedLetterMultiplier, jint fullWordMultiplier)
+         jint typedLetterMultiplier, jint fullWordMultiplier, jint maxWordLength, jint maxWords,
+         jint maxAlternatives)
 {
     void *dict = env->GetDirectBufferAddress(dictDirectBuffer);
     if (dict == NULL) {
         fprintf(stderr, "DICT: Dictionary buffer is null\n");
         return 0;
     }
-    Dictionary *dictionary = new Dictionary(dict, typedLetterMultiplier, fullWordMultiplier);
+    Dictionary *dictionary = new Dictionary(dict, typedLetterMultiplier, fullWordMultiplier,
+            maxWordLength, maxWords, maxAlternatives);
     return (jint) dictionary;
 }
 
 static int latinime_BinaryDictionary_getSuggestions(
         JNIEnv *env, jobject object, jint dict, jintArray inputArray, jint arraySize,
-        jcharArray outputArray, jintArray frequencyArray, jint maxWordLength, jint maxWords,
-        jint maxAlternatives, jint skipPos, jintArray nextLettersArray, jint nextLettersSize)
+        jcharArray outputArray, jintArray frequencyArray,
+        jintArray nextLettersArray, jint nextLettersSize)
 {
     Dictionary *dictionary = (Dictionary*) dict;
     if (dictionary == NULL) return 0;
@@ -68,8 +70,7 @@ static int latinime_BinaryDictionary_getSuggestions(
             : NULL;
 
     int count = dictionary->getSuggestions(inputCodes, arraySize, (unsigned short*) outputChars,
-            frequencies, maxWordLength, maxWords, maxAlternatives, skipPos, nextLetters,
-            nextLettersSize);
+            frequencies, nextLetters, nextLettersSize);
 
     env->ReleaseIntArrayElements(frequencyArray, frequencies, 0);
     env->ReleaseIntArrayElements(inputArray, inputCodes, JNI_ABORT);
@@ -123,17 +124,16 @@ static jboolean latinime_BinaryDictionary_isValidWord
 static void latinime_BinaryDictionary_close
         (JNIEnv *env, jobject object, jint dict)
 {
-    Dictionary *dictionary = (Dictionary*) dict;
     delete (Dictionary*) dict;
 }
 
 // ----------------------------------------------------------------------------
 
 static JNINativeMethod gMethods[] = {
-    {"openNative",           "(Ljava/nio/ByteBuffer;II)I",
+    {"openNative",           "(Ljava/nio/ByteBuffer;IIIII)I",
                                           (void*)latinime_BinaryDictionary_open},
     {"closeNative",          "(I)V",            (void*)latinime_BinaryDictionary_close},
-    {"getSuggestionsNative", "(I[II[C[IIIII[II)I",  (void*)latinime_BinaryDictionary_getSuggestions},
+    {"getSuggestionsNative", "(I[II[C[I[II)I",  (void*)latinime_BinaryDictionary_getSuggestions},
     {"isValidWordNative",    "(I[CI)Z",         (void*)latinime_BinaryDictionary_isValidWord},
     {"getBigramsNative",    "(I[CI[II[C[IIII)I",         (void*)latinime_BinaryDictionary_getBigrams}
 };
diff --git a/native/src/bigram_dictionary.cpp b/native/src/bigram_dictionary.cpp
new file mode 100644
index 000000000..4d9a612a5
--- /dev/null
+++ b/native/src/bigram_dictionary.cpp
@@ -0,0 +1,31 @@
+/*
+**
+** Copyright 2010, The Android Open Source Project
+**
+** Licensed under the Apache License, Version 2.0 (the "License");
+** you may not use this file except in compliance with the License.
+** You may obtain a copy of the License at
+**
+**     http://www.apache.org/licenses/LICENSE-2.0
+**
+** Unless required by applicable law or agreed to in writing, software
+** distributed under the License is distributed on an "AS IS" BASIS,
+** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+** See the License for the specific language governing permissions and
+** limitations under the License.
+*/
+
+#include "bigram_dictionary.h"
+
+namespace latinime {
+
+BigramDictionary::BigramDictionary(void *dict, int typedLetterMultiplier, int fullWordMultiplier,
+        int maxWordLength, int maxWords, int maxAlternatives, Dictionary *parentDictionary)
+{
+}
+
+BigramDictionary::~BigramDictionary()
+{
+}
+// TODO: Move functions related to bigram to here
+} // namespace latinime
diff --git a/native/src/bigram_dictionary.h b/native/src/bigram_dictionary.h
new file mode 100644
index 000000000..98146a0e7
--- /dev/null
+++ b/native/src/bigram_dictionary.h
@@ -0,0 +1,32 @@
+/*
+ * Copyright (C) 2010 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef LATINIME_BIGRAM_DICTIONARY_H
+#define LATINIME_BIGRAM_DICTIONARY_H
+
+namespace latinime {
+
+class Dictionary;
+class BigramDictionary {
+public:
+    BigramDictionary(void *dict, int typedLetterMultipler, int fullWordMultiplier, int maxWordLength,
+            int maxWords, int maxAlternatives, Dictionary *parentDictionary);
+    ~BigramDictionary();
+private:
+};
+// ----------------------------------------------------------------------------
+}; // namespace latinime
+#endif // LATINIME_BIGRAM_DICTIONARY_H
diff --git a/native/src/dictionary.cpp b/native/src/dictionary.cpp
index b20dc1173..a21b80a48 100644
--- a/native/src/dictionary.cpp
+++ b/native/src/dictionary.cpp
@@ -16,618 +16,23 @@
 */
 
 #include <stdio.h>
-#include <fcntl.h>
-#include <sys/mman.h>
-#include <string.h>
-
-#ifdef FLAG_DBG
-#define LOG_TAG "LatinIME: dictionary.cpp"
-#include <cutils/log.h>
-#define DEBUG_DICT 1
-#else // FLAG_DBG
-#define LOGI
-#define DEBUG_DICT 0
-#endif // FLAG_DBG
 
 #include "dictionary.h"
-#include "basechars.h"
-#include "char_utils.h"
-
-#define DICTIONARY_VERSION_MIN 200
-#define DICTIONARY_HEADER_SIZE 2
-#define NOT_VALID_WORD -99
-
-#define SUGGEST_MISSING_CHARACTERS true
-#define SUGGEST_MISSING_CHARACTERS_THRESHOLD 5
-
 
 namespace latinime {
 
-Dictionary::Dictionary(void *dict, int typedLetterMultiplier, int fullWordMultiplier)
+Dictionary::Dictionary(void *dict, int typedLetterMultiplier, int fullWordMultiplier,
+        int maxWordLength, int maxWords, int maxAlternatives)
 {
-    LOGI("Dictionary - constructor");
-    mDict = (unsigned char*) dict;
-    mTypedLetterMultiplier = typedLetterMultiplier;
-    mFullWordMultiplier = fullWordMultiplier;
-    getVersionNumber();
+    mUnigramDictionary = new UnigramDictionary(dict, typedLetterMultiplier, fullWordMultiplier,
+            maxWordLength, maxWords, maxAlternatives, this);
+    mBigramDictionary = new BigramDictionary(dict, typedLetterMultiplier, fullWordMultiplier,
+            maxWordLength, maxWords, maxAlternatives, this);
 }
 
 Dictionary::~Dictionary()
 {
+    delete mUnigramDictionary;
+    delete mBigramDictionary;
 }
-
-int Dictionary::getSuggestions(int *codes, int codesSize, unsigned short *outWords, int *frequencies,
-        int maxWordLength, int maxWords, int maxAlternatives, int skipPos,
-        int *nextLetters, int nextLettersSize)
-{
-
-    initSuggestions(codes, codesSize, outWords, frequencies, maxWordLength, maxWords,
-            maxAlternatives);
-
-    int suggestedWordsCount = getSuggestionCandidates(codesSize, maxWords, skipPos, nextLetters,
-            nextLettersSize);
-
-    // If there aren't sufficient suggestions, search for words by allowing wild cards at
-    // the different character positions. This feature is not ready for prime-time as we need
-    // to figure out the best ranking for such words compared to proximity corrections and
-    // completions.
-    if (SUGGEST_MISSING_CHARACTERS && suggestedWordsCount < SUGGEST_MISSING_CHARACTERS_THRESHOLD) {
-        for (int i = 0; i < codesSize; ++i) {
-            int tempCount = getSuggestionCandidates(codesSize, maxWords, i, NULL, 0);
-            if (tempCount > suggestedWordsCount) {
-                suggestedWordsCount = tempCount;
-                break;
-            }
-        }
-    }
-
-    if (DEBUG_DICT) {
-        LOGI("Returning %d words", suggestedWordsCount);
-        LOGI("Next letters: ");
-        for (int k = 0; k < nextLettersSize; k++) {
-            if (nextLetters[k] > 0) {
-                LOGI("%c = %d,", k, nextLetters[k]);
-            }
-        }
-        LOGI("\n");
-    }
-    return suggestedWordsCount;
-}
-
-void Dictionary::initSuggestions(int *codes, int codesSize, unsigned short *outWords,
-        int *frequencies, int maxWordLength, int maxWords, int maxAlternatives) {
-    mFrequencies = frequencies;
-    mOutputChars = outWords;
-    mInputCodes = codes;
-    mInputLength = codesSize;
-    mMaxAlternatives = maxAlternatives;
-    mMaxWordLength = maxWordLength;
-    mMaxWords = maxWords;
-    mMaxEditDistance = mInputLength < 5 ? 2 : mInputLength / 2;
-}
-
-int Dictionary::getSuggestionCandidates(int inputLength, int maxWords, int skipPos,
-        int *nextLetters, int nextLettersSize) {
-    if (checkIfDictVersionIsLatest()) {
-        getWordsRec(DICTIONARY_HEADER_SIZE, 0, inputLength * 3, false, 1, 0, 0, skipPos,
-                nextLetters, nextLettersSize);
-    } else {
-        getWordsRec(0, 0, inputLength * 3, false, 1, 0, 0, skipPos, nextLetters, nextLettersSize);
-    }
-
-    // Get the word count
-    int suggestedWordsCount = 0;
-    while (suggestedWordsCount < maxWords && mFrequencies[suggestedWordsCount] > 0) {
-        suggestedWordsCount++;
-    }
-    return suggestedWordsCount;
-}
-
-void Dictionary::registerNextLetter(unsigned short c, int *nextLetters, int nextLettersSize) {
-    if (c < nextLettersSize) {
-        nextLetters[c]++;
-    }
-}
-
-void
-Dictionary::getVersionNumber()
-{
-    mVersion = (mDict[0] & 0xFF);
-    mBigram = (mDict[1] & 0xFF);
-    LOGI("IN NATIVE SUGGEST Version: %d Bigram : %d \n", mVersion, mBigram);
-}
-
-// Checks whether it has the latest dictionary or the old dictionary
-bool
-Dictionary::checkIfDictVersionIsLatest()
-{
-    return (mVersion >= DICTIONARY_VERSION_MIN) && (mBigram == 1 || mBigram == 0);
-}
-
-unsigned short
-Dictionary::getChar(int *pos)
-{
-    unsigned short ch = (unsigned short) (mDict[(*pos)++] & 0xFF);
-    // If the code is 255, then actual 16 bit code follows (in big endian)
-    if (ch == 0xFF) {
-        ch = ((mDict[*pos] & 0xFF) << 8) | (mDict[*pos + 1] & 0xFF);
-        (*pos) += 2;
-    }
-    return ch;
-}
-
-int
-Dictionary::getAddress(int *pos)
-{
-    int address = 0;
-    if ((mDict[*pos] & FLAG_ADDRESS_MASK) == 0) {
-        *pos += 1;
-    } else {
-        address += (mDict[*pos] & (ADDRESS_MASK >> 16)) << 16;
-        address += (mDict[*pos + 1] & 0xFF) << 8;
-        address += (mDict[*pos + 2] & 0xFF);
-        *pos += 3;
-    }
-    return address;
-}
-
-int
-Dictionary::getFreq(int *pos)
-{
-    int freq = mDict[(*pos)++] & 0xFF;
-
-    if (checkIfDictVersionIsLatest()) {
-        // skipping bigram
-        int bigramExist = (mDict[*pos] & FLAG_BIGRAM_READ);
-        if (bigramExist > 0) {
-            int nextBigramExist = 1;
-            while (nextBigramExist > 0) {
-                (*pos) += 3;
-                nextBigramExist = (mDict[(*pos)++] & FLAG_BIGRAM_CONTINUED);
-            }
-        } else {
-            (*pos)++;
-        }
-    }
-
-    return freq;
-}
-
-int
-Dictionary::wideStrLen(unsigned short *str)
-{
-    if (!str) return 0;
-    unsigned short *end = str;
-    while (*end)
-        end++;
-    return end - str;
-}
-
-bool
-Dictionary::addWord(unsigned short *word, int length, int frequency)
-{
-    word[length] = 0;
-    if (DEBUG_DICT) {
-        char s[length + 1];
-        for (int i = 0; i <= length; i++) s[i] = word[i];
-        LOGI("Found word = %s, freq = %d : \n", s, frequency);
-    }
-
-    // Find the right insertion point
-    int insertAt = 0;
-    while (insertAt < mMaxWords) {
-        if (frequency > mFrequencies[insertAt]
-                 || (mFrequencies[insertAt] == frequency
-                     && length < wideStrLen(mOutputChars + insertAt * mMaxWordLength))) {
-            break;
-        }
-        insertAt++;
-    }
-    if (insertAt < mMaxWords) {
-        memmove((char*) mFrequencies + (insertAt + 1) * sizeof(mFrequencies[0]),
-               (char*) mFrequencies + insertAt * sizeof(mFrequencies[0]),
-               (mMaxWords - insertAt - 1) * sizeof(mFrequencies[0]));
-        mFrequencies[insertAt] = frequency;
-        memmove((char*) mOutputChars + (insertAt + 1) * mMaxWordLength * sizeof(short),
-               (char*) mOutputChars + (insertAt    ) * mMaxWordLength * sizeof(short),
-               (mMaxWords - insertAt - 1) * sizeof(short) * mMaxWordLength);
-        unsigned short *dest = mOutputChars + (insertAt    ) * mMaxWordLength;
-        while (length--) {
-            *dest++ = *word++;
-        }
-        *dest = 0; // NULL terminate
-        if (DEBUG_DICT) LOGI("Added word at %d\n", insertAt);
-        return true;
-    }
-    return false;
-}
-
-bool
-Dictionary::addWordBigram(unsigned short *word, int length, int frequency)
-{
-    word[length] = 0;
-    if (DEBUG_DICT) {
-        char s[length + 1];
-        for (int i = 0; i <= length; i++) s[i] = word[i];
-        LOGI("Bigram: Found word = %s, freq = %d : \n", s, frequency);
-    }
-
-    // Find the right insertion point
-    int insertAt = 0;
-    while (insertAt < mMaxBigrams) {
-        if (frequency > mBigramFreq[insertAt]
-                 || (mBigramFreq[insertAt] == frequency
-                     && length < wideStrLen(mBigramChars + insertAt * mMaxWordLength))) {
-            break;
-        }
-        insertAt++;
-    }
-    LOGI("Bigram: InsertAt -> %d maxBigrams: %d\n", insertAt, mMaxBigrams);
-    if (insertAt < mMaxBigrams) {
-        memmove((char*) mBigramFreq + (insertAt + 1) * sizeof(mBigramFreq[0]),
-               (char*) mBigramFreq + insertAt * sizeof(mBigramFreq[0]),
-               (mMaxBigrams - insertAt - 1) * sizeof(mBigramFreq[0]));
-        mBigramFreq[insertAt] = frequency;
-        memmove((char*) mBigramChars + (insertAt + 1) * mMaxWordLength * sizeof(short),
-               (char*) mBigramChars + (insertAt    ) * mMaxWordLength * sizeof(short),
-               (mMaxBigrams - insertAt - 1) * sizeof(short) * mMaxWordLength);
-        unsigned short *dest = mBigramChars + (insertAt    ) * mMaxWordLength;
-        while (length--) {
-            *dest++ = *word++;
-        }
-        *dest = 0; // NULL terminate
-        if (DEBUG_DICT) LOGI("Bigram: Added word at %d\n", insertAt);
-        return true;
-    }
-    return false;
-}
-
-unsigned short
-Dictionary::toLowerCase(unsigned short c) {
-    if (c < sizeof(BASE_CHARS) / sizeof(BASE_CHARS[0])) {
-        c = BASE_CHARS[c];
-    }
-    if (c >='A' && c <= 'Z') {
-        c |= 32;
-    } else if (c > 127) {
-        c = latin_tolower(c);
-    }
-    return c;
-}
-
-bool
-Dictionary::sameAsTyped(unsigned short *word, int length)
-{
-    if (length != mInputLength) {
-        return false;
-    }
-    int *inputCodes = mInputCodes;
-    while (length--) {
-        if ((unsigned int) *inputCodes != (unsigned int) *word) {
-            return false;
-        }
-        inputCodes += mMaxAlternatives;
-        word++;
-    }
-    return true;
-}
-
-static char QUOTE = '\'';
-
-void
-Dictionary::getWordsRec(int pos, int depth, int maxDepth, bool completion, int snr, int inputIndex,
-                        int diffs, int skipPos, int *nextLetters, int nextLettersSize)
-{
-    // Optimization: Prune out words that are too long compared to how much was typed.
-    if (depth > maxDepth) {
-        return;
-    }
-    if (diffs > mMaxEditDistance) {
-        return;
-    }
-    int count = getCount(&pos);
-    int *currentChars = NULL;
-    if (mInputLength <= inputIndex) {
-        completion = true;
-    } else {
-        currentChars = mInputCodes + (inputIndex * mMaxAlternatives);
-    }
-
-    for (int i = 0; i < count; i++) {
-        // -- at char
-        unsigned short c = getChar(&pos);
-        // -- at flag/add
-        unsigned short lowerC = toLowerCase(c);
-        bool terminal = getTerminal(&pos);
-        int childrenAddress = getAddress(&pos);
-        // -- after address or flag
-        int freq = 1;
-        if (terminal) freq = getFreq(&pos);
-        // -- after add or freq
-
-        // If we are only doing completions, no need to look at the typed characters.
-        if (completion) {
-            mWord[depth] = c;
-            if (terminal) {
-                addWord(mWord, depth + 1, freq * snr);
-                if (depth >= mInputLength && skipPos < 0) {
-                    registerNextLetter(mWord[mInputLength], nextLetters, nextLettersSize);
-                }
-            }
-            if (childrenAddress != 0) {
-                getWordsRec(childrenAddress, depth + 1, maxDepth, completion, snr, inputIndex,
-                        diffs, skipPos, nextLetters, nextLettersSize);
-            }
-        } else if ((c == QUOTE && currentChars[0] != QUOTE) || skipPos == depth) {
-            // Skip the ' or other letter and continue deeper
-            mWord[depth] = c;
-            if (childrenAddress != 0) {
-                getWordsRec(childrenAddress, depth + 1, maxDepth, false, snr, inputIndex, diffs,
-                        skipPos, nextLetters, nextLettersSize);
-            }
-        } else {
-            int j = 0;
-            while (currentChars[j] > 0) {
-                if (currentChars[j] == lowerC || currentChars[j] == c) {
-                    int addedWeight = j == 0 ? mTypedLetterMultiplier : 1;
-                    mWord[depth] = c;
-                    if (mInputLength == inputIndex + 1) {
-                        if (terminal) {
-                            if (//INCLUDE_TYPED_WORD_IF_VALID ||
-                                !sameAsTyped(mWord, depth + 1)) {
-                                int finalFreq = freq * snr * addedWeight;
-                                if (skipPos < 0) finalFreq *= mFullWordMultiplier;
-                                addWord(mWord, depth + 1, finalFreq);
-                            }
-                        }
-                        if (childrenAddress != 0) {
-                            getWordsRec(childrenAddress, depth + 1,
-                                    maxDepth, true, snr * addedWeight, inputIndex + 1,
-                                    diffs + (j > 0), skipPos, nextLetters, nextLettersSize);
-                        }
-                    } else if (childrenAddress != 0) {
-                        getWordsRec(childrenAddress, depth + 1, maxDepth,
-                                false, snr * addedWeight, inputIndex + 1, diffs + (j > 0),
-                                skipPos, nextLetters, nextLettersSize);
-                    }
-                }
-                j++;
-                if (skipPos >= 0) break;
-            }
-        }
-    }
-}
-
-int
-Dictionary::getBigramAddress(int *pos, bool advance)
-{
-    int address = 0;
-
-    address += (mDict[*pos] & 0x3F) << 16;
-    address += (mDict[*pos + 1] & 0xFF) << 8;
-    address += (mDict[*pos + 2] & 0xFF);
-
-    if (advance) {
-        *pos += 3;
-    }
-
-    return address;
-}
-
-int
-Dictionary::getBigramFreq(int *pos)
-{
-    int freq = mDict[(*pos)++] & FLAG_BIGRAM_FREQ;
-
-    return freq;
-}
-
-
-int
-Dictionary::getBigrams(unsigned short *prevWord, int prevWordLength, int *codes, int codesSize,
-        unsigned short *bigramChars, int *bigramFreq, int maxWordLength, int maxBigrams,
-        int maxAlternatives)
-{
-    mBigramFreq = bigramFreq;
-    mBigramChars = bigramChars;
-    mInputCodes = codes;
-    mInputLength = codesSize;
-    mMaxWordLength = maxWordLength;
-    mMaxBigrams = maxBigrams;
-    mMaxAlternatives = maxAlternatives;
-
-    if (mBigram == 1 && checkIfDictVersionIsLatest()) {
-        int pos = isValidWordRec(DICTIONARY_HEADER_SIZE, prevWord, 0, prevWordLength);
-        LOGI("Pos -> %d\n", pos);
-        if (pos < 0) {
-            return 0;
-        }
-
-        int bigramCount = 0;
-        int bigramExist = (mDict[pos] & FLAG_BIGRAM_READ);
-        if (bigramExist > 0) {
-            int nextBigramExist = 1;
-            while (nextBigramExist > 0 && bigramCount < maxBigrams) {
-                int bigramAddress = getBigramAddress(&pos, true);
-                int frequency = (FLAG_BIGRAM_FREQ & mDict[pos]);
-                // search for all bigrams and store them
-                searchForTerminalNode(bigramAddress, frequency);
-                nextBigramExist = (mDict[pos++] & FLAG_BIGRAM_CONTINUED);
-                bigramCount++;
-            }
-        }
-
-        return bigramCount;
-    }
-    return 0;
-}
-
-void
-Dictionary::searchForTerminalNode(int addressLookingFor, int frequency)
-{
-    // track word with such address and store it in an array
-    unsigned short word[mMaxWordLength];
-
-    int pos;
-    int followDownBranchAddress = DICTIONARY_HEADER_SIZE;
-    bool found = false;
-    char followingChar = ' ';
-    int depth = -1;
-
-    while(!found) {
-        bool followDownAddressSearchStop = false;
-        bool firstAddress = true;
-        bool haveToSearchAll = true;
-
-        if (depth >= 0) {
-            word[depth] = (unsigned short) followingChar;
-        }
-        pos = followDownBranchAddress; // pos start at count
-        int count = mDict[pos] & 0xFF;
-        LOGI("count - %d\n",count);
-        pos++;
-        for (int i = 0; i < count; i++) {
-            // pos at data
-            pos++;
-            // pos now at flag
-            if (!getFirstBitOfByte(&pos)) { // non-terminal
-                if (!followDownAddressSearchStop) {
-                    int addr = getBigramAddress(&pos, false);
-                    if (addr > addressLookingFor) {
-                        followDownAddressSearchStop = true;
-                        if (firstAddress) {
-                            firstAddress = false;
-                            haveToSearchAll = true;
-                        } else if (!haveToSearchAll) {
-                            break;
-                        }
-                    } else {
-                        followDownBranchAddress = addr;
-                        followingChar = (char)(0xFF & mDict[pos-1]);
-                        if (firstAddress) {
-                            firstAddress = false;
-                            haveToSearchAll = false;
-                        }
-                    }
-                }
-                pos += 3;
-            } else if (getFirstBitOfByte(&pos)) { // terminal
-                if (addressLookingFor == (pos-1)) { // found !!
-                    depth++;
-                    word[depth] = (0xFF & mDict[pos-1]);
-                    found = true;
-                    break;
-                }
-                if (getSecondBitOfByte(&pos)) { // address + freq (4 byte)
-                    if (!followDownAddressSearchStop) {
-                        int addr = getBigramAddress(&pos, false);
-                        if (addr > addressLookingFor) {
-                            followDownAddressSearchStop = true;
-                            if (firstAddress) {
-                                firstAddress = false;
-                                haveToSearchAll = true;
-                            } else if (!haveToSearchAll) {
-                                break;
-                            }
-                        } else {
-                            followDownBranchAddress = addr;
-                            followingChar = (char)(0xFF & mDict[pos-1]);
-                            if (firstAddress) {
-                                firstAddress = false;
-                                haveToSearchAll = true;
-                            }
-                        }
-                    }
-                    pos += 4;
-                } else { // freq only (2 byte)
-                    pos += 2;
-                }
-
-                // skipping bigram
-                int bigramExist = (mDict[pos] & FLAG_BIGRAM_READ);
-                if (bigramExist > 0) {
-                    int nextBigramExist = 1;
-                    while (nextBigramExist > 0) {
-                        pos += 3;
-                        nextBigramExist = (mDict[pos++] & FLAG_BIGRAM_CONTINUED);
-                    }
-                } else {
-                    pos++;
-                }
-            }
-        }
-        depth++;
-        if (followDownBranchAddress == 0) {
-            LOGI("ERROR!!! Cannot find bigram!!");
-            break;
-        }
-    }
-    if (checkFirstCharacter(word)) {
-        addWordBigram(word, depth, frequency);
-    }
-}
-
-bool
-Dictionary::checkFirstCharacter(unsigned short *word)
-{
-    // Checks whether this word starts with same character or neighboring characters of
-    // what user typed.
-
-    int *inputCodes = mInputCodes;
-    int maxAlt = mMaxAlternatives;
-    while (maxAlt > 0) {
-        if ((unsigned int) *inputCodes == (unsigned int) *word) {
-            return true;
-        }
-        inputCodes++;
-        maxAlt--;
-    }
-    return false;
-}
-
-bool
-Dictionary::isValidWord(unsigned short *word, int length)
-{
-    if (checkIfDictVersionIsLatest()) {
-        return (isValidWordRec(DICTIONARY_HEADER_SIZE, word, 0, length) != NOT_VALID_WORD);
-    } else {
-        return (isValidWordRec(0, word, 0, length) != NOT_VALID_WORD);
-    }
-}
-
-int
-Dictionary::isValidWordRec(int pos, unsigned short *word, int offset, int length) {
-    // returns address of bigram data of that word
-    // return -99 if not found
-
-    int count = getCount(&pos);
-    unsigned short currentChar = (unsigned short) word[offset];
-    for (int j = 0; j < count; j++) {
-        unsigned short c = getChar(&pos);
-        int terminal = getTerminal(&pos);
-        int childPos = getAddress(&pos);
-        if (c == currentChar) {
-            if (offset == length - 1) {
-                if (terminal) {
-                    return (pos+1);
-                }
-            } else {
-                if (childPos != 0) {
-                    int t = isValidWordRec(childPos, word, offset + 1, length);
-                    if (t > 0) {
-                        return t;
-                    }
-                }
-            }
-        }
-        if (terminal) {
-            getFreq(&pos);
-        }
-        // There could be two instances of each alphabet - upper and lower case. So continue
-        // looking ...
-    }
-    return NOT_VALID_WORD;
-}
-
-
 } // namespace latinime
diff --git a/native/src/dictionary.h b/native/src/dictionary.h
index 2dac3b2c4..4c1f8837c 100644
--- a/native/src/dictionary.h
+++ b/native/src/dictionary.h
@@ -17,6 +17,9 @@
 #ifndef LATINIME_DICTIONARY_H
 #define LATINIME_DICTIONARY_H
 
+#include "bigram_dictionary.h"
+#include "unigram_dictionary.h"
+
 namespace latinime {
 
 // 22-bit address = ~4MB dictionary size limit, which on average would be about 200k-300k words
@@ -35,68 +38,32 @@ namespace latinime {
 
 class Dictionary {
 public:
-    Dictionary(void *dict, int typedLetterMultipler, int fullWordMultiplier);
+    Dictionary(void *dict, int typedLetterMultipler, int fullWordMultiplier, int maxWordLength,
+            int maxWords, int maxAlternatives);
     int getSuggestions(int *codes, int codesSize, unsigned short *outWords, int *frequencies,
-            int maxWordLength, int maxWords, int maxAlternatives, int skipPos,
-            int *nextLetters, int nextLettersSize);
+            int *nextLetters, int nextLettersSize) {
+        return mUnigramDictionary->getSuggestions(codes, codesSize, outWords, frequencies,
+                nextLetters, nextLettersSize);
+    }
+
+    // TODO: Call mBigramDictionary instead of mUnigramDictionary
     int getBigrams(unsigned short *word, int length, int *codes, int codesSize,
             unsigned short *outWords, int *frequencies, int maxWordLength, int maxBigrams,
-            int maxAlternatives);
-    bool isValidWord(unsigned short *word, int length);
+            int maxAlternatives) {
+        return mUnigramDictionary->getBigrams(word, length, codes, codesSize, outWords, frequencies,
+                maxWordLength, maxBigrams, maxAlternatives);
+    }
+    bool isValidWord(unsigned short *word, int length) {
+        return mUnigramDictionary->isValidWord(word, length);
+    }
     void setAsset(void *asset) { mAsset = asset; }
     void *getAsset() { return mAsset; }
     ~Dictionary();
 
 private:
-    void initSuggestions(int *codes, int codesSize, unsigned short *outWords, int *frequencies,
-            int maxWordLength, int maxWords, int maxAlternatives);
-    int getSuggestionCandidates(int inputLength, int maxWords, int skipPos, int *nextLetters,
-            int nextLettersSize);
-    void getVersionNumber();
-    bool checkIfDictVersionIsLatest();
-    int getAddress(int *pos);
-    int getBigramAddress(int *pos, bool advance);
-    int getFreq(int *pos);
-    int getBigramFreq(int *pos);
-    void searchForTerminalNode(int address, int frequency);
-
-    bool getFirstBitOfByte(int *pos) { return (mDict[*pos] & 0x80) > 0; }
-    bool getSecondBitOfByte(int *pos) { return (mDict[*pos] & 0x40) > 0; }
-    bool getTerminal(int *pos) { return (mDict[*pos] & FLAG_TERMINAL_MASK) > 0; }
-    int getCount(int *pos) { return mDict[(*pos)++] & 0xFF; }
-    unsigned short getChar(int *pos);
-    int wideStrLen(unsigned short *str);
-
-    bool sameAsTyped(unsigned short *word, int length);
-    bool checkFirstCharacter(unsigned short *word);
-    bool addWord(unsigned short *word, int length, int frequency);
-    bool addWordBigram(unsigned short *word, int length, int frequency);
-    unsigned short toLowerCase(unsigned short c);
-    void getWordsRec(int pos, int depth, int maxDepth, bool completion, int frequency,
-            int inputIndex, int diffs, int skipPos, int *nextLetters, int nextLettersSize);
-    int isValidWordRec(int pos, unsigned short *word, int offset, int length);
-    void registerNextLetter(unsigned short c, int *nextLetters, int nextLettersSize);
-
-    unsigned char *mDict;
     void *mAsset;
-
-    int *mFrequencies;
-    int *mBigramFreq;
-    int mMaxWords;
-    int mMaxBigrams;
-    int mMaxWordLength;
-    unsigned short *mOutputChars;
-    unsigned short *mBigramChars;
-    int *mInputCodes;
-    int mInputLength;
-    int mMaxAlternatives;
-    unsigned short mWord[128];
-    int mMaxEditDistance;
-
-    int mFullWordMultiplier;
-    int mTypedLetterMultiplier;
-    int mVersion;
-    int mBigram;
+    BigramDictionary *mBigramDictionary;
+    UnigramDictionary *mUnigramDictionary;
 };
 
 // ----------------------------------------------------------------------------
diff --git a/native/src/unigram_dictionary.cpp b/native/src/unigram_dictionary.cpp
new file mode 100644
index 000000000..88382a94d
--- /dev/null
+++ b/native/src/unigram_dictionary.cpp
@@ -0,0 +1,631 @@
+/*
+**
+** Copyright 2010, The Android Open Source Project
+**
+** Licensed under the Apache License, Version 2.0 (the "License");
+** you may not use this file except in compliance with the License.
+** You may obtain a copy of the License at
+**
+**     http://www.apache.org/licenses/LICENSE-2.0
+**
+** Unless required by applicable law or agreed to in writing, software
+** distributed under the License is distributed on an "AS IS" BASIS,
+** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+** See the License for the specific language governing permissions and
+** limitations under the License.
+*/
+
+#include <stdio.h>
+#include <fcntl.h>
+#include <sys/mman.h>
+#include <string.h>
+
+#ifdef FLAG_DBG
+#define LOG_TAG "LatinIME: dictionary.cpp"
+#include <cutils/log.h>
+#define DEBUG_DICT 1
+#else // FLAG_DBG
+#define LOGI
+#define DEBUG_DICT 0
+#endif // FLAG_DBG
+
+#include "unigram_dictionary.h"
+#include "basechars.h"
+#include "char_utils.h"
+
+#define DICTIONARY_VERSION_MIN 200
+#define DICTIONARY_HEADER_SIZE 2
+#define NOT_VALID_WORD -99
+
+#define SUGGEST_MISSING_CHARACTERS true
+#define SUGGEST_MISSING_CHARACTERS_THRESHOLD 5
+
+
+namespace latinime {
+
+UnigramDictionary::UnigramDictionary(void *dict, int typedLetterMultiplier, int fullWordMultiplier,
+        int maxWordLength, int maxWords, int maxAlternatives, Dictionary *parentDictionary)
+    : MAX_WORD_LENGTH(maxWordLength),MAX_WORDS(maxWords), MAX_ALTERNATIVES(maxAlternatives)
+{
+    LOGI("UnigramDictionary - constructor");
+    mDict = (unsigned char*) dict;
+    mTypedLetterMultiplier = typedLetterMultiplier;
+    mFullWordMultiplier = fullWordMultiplier;
+    mParentDictionary = parentDictionary;
+    getVersionNumber();
+}
+
+UnigramDictionary::~UnigramDictionary()
+{
+}
+
+int UnigramDictionary::getSuggestions(int *codes, int codesSize, unsigned short *outWords, int *frequencies,
+        int *nextLetters, int nextLettersSize)
+{
+
+    initSuggestions(codes, codesSize, outWords, frequencies);
+
+    int suggestedWordsCount = getSuggestionCandidates(codesSize, -1, nextLetters,
+            nextLettersSize);
+
+    // If there aren't sufficient suggestions, search for words by allowing wild cards at
+    // the different character positions. This feature is not ready for prime-time as we need
+    // to figure out the best ranking for such words compared to proximity corrections and
+    // completions.
+    if (SUGGEST_MISSING_CHARACTERS && suggestedWordsCount < SUGGEST_MISSING_CHARACTERS_THRESHOLD) {
+        for (int i = 0; i < codesSize; ++i) {
+            int tempCount = getSuggestionCandidates(codesSize, i, NULL, 0);
+            if (tempCount > suggestedWordsCount) {
+                suggestedWordsCount = tempCount;
+                break;
+            }
+        }
+    }
+
+    if (DEBUG_DICT) {
+        LOGI("Returning %d words", suggestedWordsCount);
+        LOGI("Next letters: ");
+        for (int k = 0; k < nextLettersSize; k++) {
+            if (nextLetters[k] > 0) {
+                LOGI("%c = %d,", k, nextLetters[k]);
+            }
+        }
+        LOGI("\n");
+    }
+    return suggestedWordsCount;
+}
+
+void UnigramDictionary::initSuggestions(int *codes, int codesSize, unsigned short *outWords,
+        int *frequencies) {
+    mFrequencies = frequencies;
+    mOutputChars = outWords;
+    mInputCodes = codes;
+    mInputLength = codesSize;
+    mMaxEditDistance = mInputLength < 5 ? 2 : mInputLength / 2;
+}
+
+int UnigramDictionary::getSuggestionCandidates(int inputLength, int skipPos,
+        int *nextLetters, int nextLettersSize) {
+    if (checkIfDictVersionIsLatest()) {
+        getWordsRec(DICTIONARY_HEADER_SIZE, 0, inputLength * 3, false, 1, 0, 0, skipPos,
+                nextLetters, nextLettersSize);
+    } else {
+        getWordsRec(0, 0, inputLength * 3, false, 1, 0, 0, skipPos, nextLetters, nextLettersSize);
+    }
+
+    // Get the word count
+    int suggestedWordsCount = 0;
+    while (suggestedWordsCount < MAX_WORDS && mFrequencies[suggestedWordsCount] > 0) {
+        suggestedWordsCount++;
+    }
+    return suggestedWordsCount;
+}
+
+void UnigramDictionary::registerNextLetter(unsigned short c, int *nextLetters, int nextLettersSize) {
+    if (c < nextLettersSize) {
+        nextLetters[c]++;
+    }
+}
+
+// TODO: Should be const static variable calculate in the constructor
+void
+UnigramDictionary::getVersionNumber()
+{
+    mVersion = (mDict[0] & 0xFF);
+    mBigram = (mDict[1] & 0xFF);
+    LOGI("IN NATIVE SUGGEST Version: %d Bigram : %d \n", mVersion, mBigram);
+}
+
+// TODO: Should be const static variable calculate in the constructor
+// Checks whether it has the latest dictionary or the old dictionary
+bool
+UnigramDictionary::checkIfDictVersionIsLatest()
+{
+    return (mVersion >= DICTIONARY_VERSION_MIN) && (mBigram == 1 || mBigram == 0);
+}
+
+unsigned short
+UnigramDictionary::getChar(int *pos)
+{
+    unsigned short ch = (unsigned short) (mDict[(*pos)++] & 0xFF);
+    // If the code is 255, then actual 16 bit code follows (in big endian)
+    if (ch == 0xFF) {
+        ch = ((mDict[*pos] & 0xFF) << 8) | (mDict[*pos + 1] & 0xFF);
+        (*pos) += 2;
+    }
+    return ch;
+}
+
+int
+UnigramDictionary::getAddress(int *pos)
+{
+    int address = 0;
+    if ((mDict[*pos] & FLAG_ADDRESS_MASK) == 0) {
+        *pos += 1;
+    } else {
+        address += (mDict[*pos] & (ADDRESS_MASK >> 16)) << 16;
+        address += (mDict[*pos + 1] & 0xFF) << 8;
+        address += (mDict[*pos + 2] & 0xFF);
+        *pos += 3;
+    }
+    return address;
+}
+
+int
+UnigramDictionary::getFreq(int *pos)
+{
+    int freq = mDict[(*pos)++] & 0xFF;
+
+    if (checkIfDictVersionIsLatest()) {
+        // skipping bigram
+        int bigramExist = (mDict[*pos] & FLAG_BIGRAM_READ);
+        if (bigramExist > 0) {
+            int nextBigramExist = 1;
+            while (nextBigramExist > 0) {
+                (*pos) += 3;
+                nextBigramExist = (mDict[(*pos)++] & FLAG_BIGRAM_CONTINUED);
+            }
+        } else {
+            (*pos)++;
+        }
+    }
+
+    return freq;
+}
+
+int
+UnigramDictionary::wideStrLen(unsigned short *str)
+{
+    if (!str) return 0;
+    unsigned short *end = str;
+    while (*end)
+        end++;
+    return end - str;
+}
+
+bool
+UnigramDictionary::addWord(unsigned short *word, int length, int frequency)
+{
+    word[length] = 0;
+    if (DEBUG_DICT) {
+        char s[length + 1];
+        for (int i = 0; i <= length; i++) s[i] = word[i];
+        LOGI("Found word = %s, freq = %d : \n", s, frequency);
+    }
+
+    // Find the right insertion point
+    int insertAt = 0;
+    while (insertAt < MAX_WORDS) {
+        if (frequency > mFrequencies[insertAt]
+                 || (mFrequencies[insertAt] == frequency
+                     && length < wideStrLen(mOutputChars + insertAt * MAX_WORD_LENGTH))) {
+            break;
+        }
+        insertAt++;
+    }
+    if (insertAt < MAX_WORDS) {
+        memmove((char*) mFrequencies + (insertAt + 1) * sizeof(mFrequencies[0]),
+               (char*) mFrequencies + insertAt * sizeof(mFrequencies[0]),
+               (MAX_WORDS - insertAt - 1) * sizeof(mFrequencies[0]));
+        mFrequencies[insertAt] = frequency;
+        memmove((char*) mOutputChars + (insertAt + 1) * MAX_WORD_LENGTH * sizeof(short),
+               (char*) mOutputChars + (insertAt    ) * MAX_WORD_LENGTH * sizeof(short),
+               (MAX_WORDS - insertAt - 1) * sizeof(short) * MAX_WORD_LENGTH);
+        unsigned short *dest = mOutputChars + (insertAt    ) * MAX_WORD_LENGTH;
+        while (length--) {
+            *dest++ = *word++;
+        }
+        *dest = 0; // NULL terminate
+        if (DEBUG_DICT) LOGI("Added word at %d\n", insertAt);
+        return true;
+    }
+    return false;
+}
+
+bool
+UnigramDictionary::addWordBigram(unsigned short *word, int length, int frequency)
+{
+    word[length] = 0;
+    if (DEBUG_DICT) {
+        char s[length + 1];
+        for (int i = 0; i <= length; i++) s[i] = word[i];
+        LOGI("Bigram: Found word = %s, freq = %d : \n", s, frequency);
+    }
+
+    // Find the right insertion point
+    int insertAt = 0;
+    while (insertAt < mMaxBigrams) {
+        if (frequency > mBigramFreq[insertAt]
+                 || (mBigramFreq[insertAt] == frequency
+                     && length < wideStrLen(mBigramChars + insertAt * MAX_WORD_LENGTH))) {
+            break;
+        }
+        insertAt++;
+    }
+    LOGI("Bigram: InsertAt -> %d maxBigrams: %d\n", insertAt, mMaxBigrams);
+    if (insertAt < mMaxBigrams) {
+        memmove((char*) mBigramFreq + (insertAt + 1) * sizeof(mBigramFreq[0]),
+               (char*) mBigramFreq + insertAt * sizeof(mBigramFreq[0]),
+               (mMaxBigrams - insertAt - 1) * sizeof(mBigramFreq[0]));
+        mBigramFreq[insertAt] = frequency;
+        memmove((char*) mBigramChars + (insertAt + 1) * MAX_WORD_LENGTH * sizeof(short),
+               (char*) mBigramChars + (insertAt    ) * MAX_WORD_LENGTH * sizeof(short),
+               (mMaxBigrams - insertAt - 1) * sizeof(short) * MAX_WORD_LENGTH);
+        unsigned short *dest = mBigramChars + (insertAt    ) * MAX_WORD_LENGTH;
+        while (length--) {
+            *dest++ = *word++;
+        }
+        *dest = 0; // NULL terminate
+        if (DEBUG_DICT) LOGI("Bigram: Added word at %d\n", insertAt);
+        return true;
+    }
+    return false;
+}
+
+unsigned short
+UnigramDictionary::toLowerCase(unsigned short c) {
+    if (c < sizeof(BASE_CHARS) / sizeof(BASE_CHARS[0])) {
+        c = BASE_CHARS[c];
+    }
+    if (c >='A' && c <= 'Z') {
+        c |= 32;
+    } else if (c > 127) {
+        c = latin_tolower(c);
+    }
+    return c;
+}
+
+bool
+UnigramDictionary::sameAsTyped(unsigned short *word, int length)
+{
+    if (length != mInputLength) {
+        return false;
+    }
+    int *inputCodes = mInputCodes;
+    while (length--) {
+        if ((unsigned int) *inputCodes != (unsigned int) *word) {
+            return false;
+        }
+        inputCodes += MAX_ALTERNATIVES;
+        word++;
+    }
+    return true;
+}
+
+static char QUOTE = '\'';
+
+void
+UnigramDictionary::getWordsRec(int pos, int depth, int maxDepth, bool completion, int snr, int inputIndex,
+                        int diffs, int skipPos, int *nextLetters, int nextLettersSize)
+{
+    // Optimization: Prune out words that are too long compared to how much was typed.
+    if (depth > maxDepth) {
+        return;
+    }
+    if (diffs > mMaxEditDistance) {
+        return;
+    }
+    int count = getCount(&pos);
+    int *currentChars = NULL;
+    if (mInputLength <= inputIndex) {
+        completion = true;
+    } else {
+        currentChars = mInputCodes + (inputIndex * MAX_ALTERNATIVES);
+    }
+
+    for (int i = 0; i < count; i++) {
+        // -- at char
+        unsigned short c = getChar(&pos);
+        // -- at flag/add
+        unsigned short lowerC = toLowerCase(c);
+        bool terminal = getTerminal(&pos);
+        int childrenAddress = getAddress(&pos);
+        // -- after address or flag
+        int freq = 1;
+        if (terminal) freq = getFreq(&pos);
+        // -- after add or freq
+
+        // If we are only doing completions, no need to look at the typed characters.
+        if (completion) {
+            mWord[depth] = c;
+            if (terminal) {
+                addWord(mWord, depth + 1, freq * snr);
+                if (depth >= mInputLength && skipPos < 0) {
+                    registerNextLetter(mWord[mInputLength], nextLetters, nextLettersSize);
+                }
+            }
+            if (childrenAddress != 0) {
+                getWordsRec(childrenAddress, depth + 1, maxDepth, completion, snr, inputIndex,
+                        diffs, skipPos, nextLetters, nextLettersSize);
+            }
+        } else if ((c == QUOTE && currentChars[0] != QUOTE) || skipPos == depth) {
+            // Skip the ' or other letter and continue deeper
+            mWord[depth] = c;
+            if (childrenAddress != 0) {
+                getWordsRec(childrenAddress, depth + 1, maxDepth, false, snr, inputIndex, diffs,
+                        skipPos, nextLetters, nextLettersSize);
+            }
+        } else {
+            int j = 0;
+            while (currentChars[j] > 0) {
+                if (currentChars[j] == lowerC || currentChars[j] == c) {
+                    int addedWeight = j == 0 ? mTypedLetterMultiplier : 1;
+                    mWord[depth] = c;
+                    if (mInputLength == inputIndex + 1) {
+                        if (terminal) {
+                            if (//INCLUDE_TYPED_WORD_IF_VALID ||
+                                !sameAsTyped(mWord, depth + 1)) {
+                                int finalFreq = freq * snr * addedWeight;
+                                if (skipPos < 0) finalFreq *= mFullWordMultiplier;
+                                addWord(mWord, depth + 1, finalFreq);
+                            }
+                        }
+                        if (childrenAddress != 0) {
+                            getWordsRec(childrenAddress, depth + 1,
+                                    maxDepth, true, snr * addedWeight, inputIndex + 1,
+                                    diffs + (j > 0), skipPos, nextLetters, nextLettersSize);
+                        }
+                    } else if (childrenAddress != 0) {
+                        getWordsRec(childrenAddress, depth + 1, maxDepth,
+                                false, snr * addedWeight, inputIndex + 1, diffs + (j > 0),
+                                skipPos, nextLetters, nextLettersSize);
+                    }
+                }
+                j++;
+                if (skipPos >= 0) break;
+            }
+        }
+    }
+}
+
+int
+UnigramDictionary::getBigramAddress(int *pos, bool advance)
+{
+    int address = 0;
+
+    address += (mDict[*pos] & 0x3F) << 16;
+    address += (mDict[*pos + 1] & 0xFF) << 8;
+    address += (mDict[*pos + 2] & 0xFF);
+
+    if (advance) {
+        *pos += 3;
+    }
+
+    return address;
+}
+
+int
+UnigramDictionary::getBigramFreq(int *pos)
+{
+    int freq = mDict[(*pos)++] & FLAG_BIGRAM_FREQ;
+
+    return freq;
+}
+
+
+int
+UnigramDictionary::getBigrams(unsigned short *prevWord, int prevWordLength, int *codes, int codesSize,
+        unsigned short *bigramChars, int *bigramFreq, int maxWordLength, int maxBigrams,
+        int maxAlternatives)
+{
+    mBigramFreq = bigramFreq;
+    mBigramChars = bigramChars;
+    mInputCodes = codes;
+    mInputLength = codesSize;
+    mMaxBigrams = maxBigrams;
+
+    if (mBigram == 1 && checkIfDictVersionIsLatest()) {
+        int pos = isValidWordRec(
+                DICTIONARY_HEADER_SIZE, prevWord, 0, prevWordLength);
+        LOGI("Pos -> %d\n", pos);
+        if (pos < 0) {
+            return 0;
+        }
+
+        int bigramCount = 0;
+        int bigramExist = (mDict[pos] & FLAG_BIGRAM_READ);
+        if (bigramExist > 0) {
+            int nextBigramExist = 1;
+            while (nextBigramExist > 0 && bigramCount < maxBigrams) {
+                int bigramAddress = getBigramAddress(&pos, true);
+                int frequency = (FLAG_BIGRAM_FREQ & mDict[pos]);
+                // search for all bigrams and store them
+                searchForTerminalNode(bigramAddress, frequency);
+                nextBigramExist = (mDict[pos++] & FLAG_BIGRAM_CONTINUED);
+                bigramCount++;
+            }
+        }
+
+        return bigramCount;
+    }
+    return 0;
+}
+
+void
+UnigramDictionary::searchForTerminalNode(int addressLookingFor, int frequency)
+{
+    // track word with such address and store it in an array
+    unsigned short word[MAX_WORD_LENGTH];
+
+    int pos;
+    int followDownBranchAddress = DICTIONARY_HEADER_SIZE;
+    bool found = false;
+    char followingChar = ' ';
+    int depth = -1;
+
+    while(!found) {
+        bool followDownAddressSearchStop = false;
+        bool firstAddress = true;
+        bool haveToSearchAll = true;
+
+        if (depth >= 0) {
+            word[depth] = (unsigned short) followingChar;
+        }
+        pos = followDownBranchAddress; // pos start at count
+        int count = mDict[pos] & 0xFF;
+        LOGI("count - %d\n",count);
+        pos++;
+        for (int i = 0; i < count; i++) {
+            // pos at data
+            pos++;
+            // pos now at flag
+            if (!getFirstBitOfByte(&pos)) { // non-terminal
+                if (!followDownAddressSearchStop) {
+                    int addr = getBigramAddress(&pos, false);
+                    if (addr > addressLookingFor) {
+                        followDownAddressSearchStop = true;
+                        if (firstAddress) {
+                            firstAddress = false;
+                            haveToSearchAll = true;
+                        } else if (!haveToSearchAll) {
+                            break;
+                        }
+                    } else {
+                        followDownBranchAddress = addr;
+                        followingChar = (char)(0xFF & mDict[pos-1]);
+                        if (firstAddress) {
+                            firstAddress = false;
+                            haveToSearchAll = false;
+                        }
+                    }
+                }
+                pos += 3;
+            } else if (getFirstBitOfByte(&pos)) { // terminal
+                if (addressLookingFor == (pos-1)) { // found !!
+                    depth++;
+                    word[depth] = (0xFF & mDict[pos-1]);
+                    found = true;
+                    break;
+                }
+                if (getSecondBitOfByte(&pos)) { // address + freq (4 byte)
+                    if (!followDownAddressSearchStop) {
+                        int addr = getBigramAddress(&pos, false);
+                        if (addr > addressLookingFor) {
+                            followDownAddressSearchStop = true;
+                            if (firstAddress) {
+                                firstAddress = false;
+                                haveToSearchAll = true;
+                            } else if (!haveToSearchAll) {
+                                break;
+                            }
+                        } else {
+                            followDownBranchAddress = addr;
+                            followingChar = (char)(0xFF & mDict[pos-1]);
+                            if (firstAddress) {
+                                firstAddress = false;
+                                haveToSearchAll = true;
+                            }
+                        }
+                    }
+                    pos += 4;
+                } else { // freq only (2 byte)
+                    pos += 2;
+                }
+
+                // skipping bigram
+                int bigramExist = (mDict[pos] & FLAG_BIGRAM_READ);
+                if (bigramExist > 0) {
+                    int nextBigramExist = 1;
+                    while (nextBigramExist > 0) {
+                        pos += 3;
+                        nextBigramExist = (mDict[pos++] & FLAG_BIGRAM_CONTINUED);
+                    }
+                } else {
+                    pos++;
+                }
+            }
+        }
+        depth++;
+        if (followDownBranchAddress == 0) {
+            LOGI("ERROR!!! Cannot find bigram!!");
+            break;
+        }
+    }
+    if (checkFirstCharacter(word)) {
+        addWordBigram(word, depth, frequency);
+    }
+}
+
+bool
+UnigramDictionary::checkFirstCharacter(unsigned short *word)
+{
+    // Checks whether this word starts with same character or neighboring characters of
+    // what user typed.
+
+    int *inputCodes = mInputCodes;
+    int maxAlt = MAX_ALTERNATIVES;
+    while (maxAlt > 0) {
+        if ((unsigned int) *inputCodes == (unsigned int) *word) {
+            return true;
+        }
+        inputCodes++;
+        maxAlt--;
+    }
+    return false;
+}
+
+// TODO: Move to parent dictionary
+bool
+UnigramDictionary::isValidWord(unsigned short *word, int length)
+{
+    if (checkIfDictVersionIsLatest()) {
+        return (isValidWordRec(DICTIONARY_HEADER_SIZE, word, 0, length) != NOT_VALID_WORD);
+    } else {
+        return (isValidWordRec(0, word, 0, length) != NOT_VALID_WORD);
+    }
+}
+
+int
+UnigramDictionary::isValidWordRec(int pos, unsigned short *word, int offset, int length) {
+    // returns address of bigram data of that word
+    // return -99 if not found
+
+    int count = getCount(&pos);
+    unsigned short currentChar = (unsigned short) word[offset];
+    for (int j = 0; j < count; j++) {
+        unsigned short c = getChar(&pos);
+        int terminal = getTerminal(&pos);
+        int childPos = getAddress(&pos);
+        if (c == currentChar) {
+            if (offset == length - 1) {
+                if (terminal) {
+                    return (pos+1);
+                }
+            } else {
+                if (childPos != 0) {
+                    int t = isValidWordRec(childPos, word, offset + 1, length);
+                    if (t > 0) {
+                        return t;
+                    }
+                }
+            }
+        }
+        if (terminal) {
+            getFreq(&pos);
+        }
+        // There could be two instances of each alphabet - upper and lower case. So continue
+        // looking ...
+    }
+    return NOT_VALID_WORD;
+}
+} // namespace latinime
diff --git a/native/src/unigram_dictionary.h b/native/src/unigram_dictionary.h
new file mode 100644
index 000000000..28e4308b4
--- /dev/null
+++ b/native/src/unigram_dictionary.h
@@ -0,0 +1,104 @@
+/*
+ * Copyright (C) 2010 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef LATINIME_UNIGRAM_DICTIONARY_H
+#define LATINIME_UNIGRAM_DICTIONARY_H
+
+namespace latinime {
+
+// 22-bit address = ~4MB dictionary size limit, which on average would be about 200k-300k words
+#define ADDRESS_MASK 0x3FFFFF
+
+// The bit that decides if an address follows in the next 22 bits
+#define FLAG_ADDRESS_MASK 0x40
+// The bit that decides if this is a terminal node for a word. The node could still have children,
+// if the word has other endings.
+#define FLAG_TERMINAL_MASK 0x80
+
+#define FLAG_BIGRAM_READ 0x80
+#define FLAG_BIGRAM_CHILDEXIST 0x40
+#define FLAG_BIGRAM_CONTINUED 0x80
+#define FLAG_BIGRAM_FREQ 0x7F
+
+class Dictionary;
+class UnigramDictionary {
+public:
+    UnigramDictionary(void *dict, int typedLetterMultipler, int fullWordMultiplier, int maxWordLength,
+            int maxWords, int maxAlternatives, Dictionary *parentDictionary);
+    int getSuggestions(int *codes, int codesSize, unsigned short *outWords, int *frequencies,
+            int *nextLetters, int nextLettersSize);
+    int getBigrams(unsigned short *word, int length, int *codes, int codesSize,
+            unsigned short *outWords, int *frequencies, int maxWordLength, int maxBigrams,
+            int maxAlternatives);
+    bool isValidWord(unsigned short *word, int length);
+    ~UnigramDictionary();
+
+private:
+    void initSuggestions(int *codes, int codesSize, unsigned short *outWords, int *frequencies);
+    int getSuggestionCandidates(int inputLength, int skipPos, int *nextLetters, int nextLettersSize);
+    void getVersionNumber();
+    bool checkIfDictVersionIsLatest();
+    int getAddress(int *pos);
+    int getBigramAddress(int *pos, bool advance);
+    int getFreq(int *pos);
+    int getBigramFreq(int *pos);
+    void searchForTerminalNode(int address, int frequency);
+
+    bool getFirstBitOfByte(int *pos) { return (mDict[*pos] & 0x80) > 0; }
+    bool getSecondBitOfByte(int *pos) { return (mDict[*pos] & 0x40) > 0; }
+    bool getTerminal(int *pos) { return (mDict[*pos] & FLAG_TERMINAL_MASK) > 0; }
+    int getCount(int *pos) { return mDict[(*pos)++] & 0xFF; }
+    unsigned short getChar(int *pos);
+    int wideStrLen(unsigned short *str);
+
+    bool sameAsTyped(unsigned short *word, int length);
+    bool checkFirstCharacter(unsigned short *word);
+    bool addWord(unsigned short *word, int length, int frequency);
+    bool addWordBigram(unsigned short *word, int length, int frequency);
+    unsigned short toLowerCase(unsigned short c);
+    void getWordsRec(int pos, int depth, int maxDepth, bool completion, int frequency,
+            int inputIndex, int diffs, int skipPos, int *nextLetters, int nextLettersSize);
+    void registerNextLetter(unsigned short c, int *nextLetters, int nextLettersSize);
+    int isValidWordRec(int pos, unsigned short *word, int offset, int length);
+
+    unsigned char *mDict;
+    Dictionary *mParentDictionary;
+
+    const int MAX_WORDS;
+    const int MAX_WORD_LENGTH;
+    const int MAX_ALTERNATIVES;
+
+    int *mFrequencies;
+    int *mBigramFreq;
+    int mMaxBigrams;
+    unsigned short *mOutputChars;
+    unsigned short *mBigramChars;
+    int *mInputCodes;
+    int mInputLength;
+    unsigned short mWord[128];
+    int mMaxEditDistance;
+
+    int mFullWordMultiplier;
+    int mTypedLetterMultiplier;
+    int mVersion;
+    int mBigram;
+};
+
+// ----------------------------------------------------------------------------
+
+}; // namespace latinime
+
+#endif // LATINIME_UNIGRAM_DICTIONARY_H