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
25namespace latinime {
26
27/**
28 * Helper class used to keep track of read accesses for a given memory region.
29 */
30class 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 */
62class 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