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:
ReadOnlyByteArrayView()32     ReadOnlyByteArrayView() : mPtr(nullptr), mSize(0) {}
33 
ReadOnlyByteArrayView(const uint8_t * const ptr,const size_t size)34     ReadOnlyByteArrayView(const uint8_t *const ptr, const size_t size)
35             : mPtr(ptr), mSize(size) {}
36 
size()37     AK_FORCE_INLINE size_t size() const {
38         return mSize;
39     }
40 
data()41     AK_FORCE_INLINE const uint8_t *data() const {
42         return mPtr;
43     }
44 
skip(const size_t n)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:
ReadWriteByteArrayView()64     ReadWriteByteArrayView() : mPtr(nullptr), mSize(0) {}
65 
ReadWriteByteArrayView(uint8_t * const ptr,const size_t size)66     ReadWriteByteArrayView(uint8_t *const ptr, const size_t size)
67             : mPtr(ptr), mSize(size) {}
68 
size()69     AK_FORCE_INLINE size_t size() const {
70         return mSize;
71     }
72 
data()73     AK_FORCE_INLINE uint8_t *data() const {
74         return mPtr;
75     }
76 
getReadOnlyView()77     AK_FORCE_INLINE ReadOnlyByteArrayView getReadOnlyView() const {
78         return ReadOnlyByteArrayView(mPtr, mSize);
79     }
80 
subView(const size_t start,const size_t n)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