Home | History | Annotate | Download | only in bigram 
      1 /*
      2  * Copyright (C) 2013 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #ifndef LATINIME_BIGRAM_LIST_READ_WRITE_UTILS_H
     18 #define LATINIME_BIGRAM_LIST_READ_WRITE_UTILS_H
     19 
     20 #include <cstdint>
     21 #include <cstdlib>
     22 
     23 #include "defines.h"
     24 #include "utils/byte_array_view.h"
     25 
     26 namespace latinime {
     27 
     28 class BufferWithExtendableBuffer;
     29 
     30 class BigramListReadWriteUtils {
     31 public:
     32    typedef uint8_t BigramFlags;
     33 
     34    static bool getBigramEntryPropertiesAndAdvancePosition(const ReadOnlyByteArrayView buffer,
     35            BigramFlags *const outBigramFlags, int *const outTargetPtNodePos,
     36            int *const bigramEntryPos);
     37 
     38    static AK_FORCE_INLINE int getProbabilityFromFlags(const BigramFlags flags) {
     39        return flags & MASK_ATTRIBUTE_PROBABILITY;
     40    }
     41 
     42    static AK_FORCE_INLINE bool hasNext(const BigramFlags flags) {
     43        return (flags & FLAG_ATTRIBUTE_HAS_NEXT) != 0;
     44    }
     45 
     46    // Bigrams reading methods
     47    static bool skipExistingBigrams(const ReadOnlyByteArrayView buffer, int *const bigramListPos);
     48 
     49 private:
     50    DISALLOW_IMPLICIT_CONSTRUCTORS(BigramListReadWriteUtils);
     51 
     52    static const BigramFlags MASK_ATTRIBUTE_ADDRESS_TYPE;
     53    static const BigramFlags FLAG_ATTRIBUTE_ADDRESS_TYPE_ONEBYTE;
     54    static const BigramFlags FLAG_ATTRIBUTE_ADDRESS_TYPE_TWOBYTES;
     55    static const BigramFlags FLAG_ATTRIBUTE_ADDRESS_TYPE_THREEBYTES;
     56    static const BigramFlags FLAG_ATTRIBUTE_OFFSET_NEGATIVE;
     57    static const BigramFlags FLAG_ATTRIBUTE_HAS_NEXT;
     58    static const BigramFlags MASK_ATTRIBUTE_PROBABILITY;
     59 
     60    static AK_FORCE_INLINE bool isOffsetNegative(const BigramFlags flags) {
     61        return (flags & FLAG_ATTRIBUTE_OFFSET_NEGATIVE) != 0;
     62    }
     63 
     64    static int getBigramAddressAndAdvancePosition(const ReadOnlyByteArrayView buffer,
     65            const BigramFlags flags, int *const pos);
     66 };
     67 } // namespace latinime
     68 #endif // LATINIME_BIGRAM_LIST_READ_WRITE_UTILS_H
     69