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      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_DYNAMIC_PATRICIA_TRIE_READING_UTILS_H
     18 #define LATINIME_DYNAMIC_PATRICIA_TRIE_READING_UTILS_H
     19 
     20 #include <stdint.h>
     21 
     22 #include "defines.h"
     23 
     24 namespace latinime {
     25 
     26 class DynamicPatriciaTrieReadingUtils {
     27  public:
     28     typedef uint8_t NodeFlags;
     29 
     30     static const int DICT_OFFSET_INVALID;
     31     static const int DICT_OFFSET_ZERO_OFFSET;
     32 
     33     static int getForwardLinkPosition(const uint8_t *const buffer, const int pos);
     34 
     35     static AK_FORCE_INLINE bool isValidForwardLinkPosition(const int forwardLinkAddress) {
     36         return forwardLinkAddress != 0;
     37     }
     38 
     39     static int getParentPtNodePosOffsetAndAdvancePosition(const uint8_t *const buffer,
     40             int *const pos);
     41 
     42     static int getParentPtNodePos(const int parentOffset, const int ptNodePos);
     43 
     44     static int readChildrenPositionAndAdvancePosition(const uint8_t *const buffer, int *const pos);
     45 
     46     /**
     47      * Node Flags
     48      */
     49     static AK_FORCE_INLINE bool isMoved(const NodeFlags flags) {
     50         return FLAG_IS_MOVED == (MASK_MOVED & flags);
     51     }
     52 
     53     static AK_FORCE_INLINE bool isDeleted(const NodeFlags flags) {
     54         return FLAG_IS_DELETED == (MASK_MOVED & flags);
     55     }
     56 
     57     static AK_FORCE_INLINE NodeFlags updateAndGetFlags(const NodeFlags originalFlags,
     58             const bool isMoved, const bool isDeleted) {
     59         NodeFlags flags = originalFlags;
     60         flags = isMoved ? ((flags & (~MASK_MOVED)) | FLAG_IS_MOVED) : flags;
     61         flags = isDeleted ? ((flags & (~MASK_MOVED)) | FLAG_IS_DELETED) : flags;
     62         flags = (!isMoved && !isDeleted) ? ((flags & (~MASK_MOVED)) | FLAG_IS_NOT_MOVED) : flags;
     63         return flags;
     64     }
     65 
     66  private:
     67     DISALLOW_IMPLICIT_CONSTRUCTORS(DynamicPatriciaTrieReadingUtils);
     68 
     69     static const NodeFlags MASK_MOVED;
     70     static const NodeFlags FLAG_IS_NOT_MOVED;
     71     static const NodeFlags FLAG_IS_MOVED;
     72     static const NodeFlags FLAG_IS_DELETED;
     73 };
     74 } // namespace latinime
     75 #endif /* LATINIME_DYNAMIC_PATRICIA_TRIE_READING_UTILS_H */
     76