Home | History | Annotate | Download | only in utils 
      1 /*
      2  * Copyright (C) 2014 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_BYTE_ARRAY_VIEW_H
     18 #define LATINIME_BYTE_ARRAY_VIEW_H
     19 
     20 #include <cstdint>
     21 #include <cstdlib>
     22 
     23 #include "defines.h"
     24 
     25 namespace latinime {
     26 
     27 /**
     28  * Helper class used to keep track of read accesses for a given memory region.
     29  */
     30 class ReadOnlyByteArrayView {
     31  public:
     32     ReadOnlyByteArrayView() : mPtr(nullptr), mSize(0) {}
     33 
     34     ReadOnlyByteArrayView(const uint8_t *const ptr, const size_t size)
     35             : mPtr(ptr), mSize(size) {}
     36 
     37     AK_FORCE_INLINE size_t size() const {
     38         return mSize;
     39     }
     40 
     41     AK_FORCE_INLINE const uint8_t *data() const {
     42         return mPtr;
     43     }
     44 
     45     AK_FORCE_INLINE const ReadOnlyByteArrayView skip(const size_t n) const {
     46         if (mSize <= n) {
     47             return ReadOnlyByteArrayView();
     48         }
     49         return ReadOnlyByteArrayView(mPtr + n, mSize - n);
     50     }
     51 
     52  private:
     53     DISALLOW_ASSIGNMENT_OPERATOR(ReadOnlyByteArrayView);
     54 
     55     const uint8_t *const mPtr;
     56     const size_t mSize;
     57 };
     58 
     59 /**
     60  * Helper class used to keep track of read-write accesses for a given memory region.
     61  */
     62 class ReadWriteByteArrayView {
     63  public:
     64     ReadWriteByteArrayView() : mPtr(nullptr), mSize(0) {}
     65 
     66     ReadWriteByteArrayView(uint8_t *const ptr, const size_t size)
     67             : mPtr(ptr), mSize(size) {}
     68 
     69     AK_FORCE_INLINE size_t size() const {
     70         return mSize;
     71     }
     72 
     73     AK_FORCE_INLINE uint8_t *data() const {
     74         return mPtr;
     75     }
     76 
     77     AK_FORCE_INLINE ReadOnlyByteArrayView getReadOnlyView() const {
     78         return ReadOnlyByteArrayView(mPtr, mSize);
     79     }
     80 
     81     ReadWriteByteArrayView subView(const size_t start, const size_t n) const {
     82         ASSERT(start + n <= mSize);
     83         return ReadWriteByteArrayView(mPtr + start, n);
     84     }
     85 
     86  private:
     87     // Default copy constructor and assignment operator are used for using this class with STL
     88     // containers.
     89 
     90     // These members cannot be const to have the assignment operator.
     91     uint8_t *mPtr;
     92     size_t mSize;
     93 };
     94 
     95 } // namespace latinime
     96 #endif // LATINIME_BYTE_ARRAY_VIEW_H
     97