1/*
2 * Copyright (C) 2018 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 MINIKIN_BIDI_UTILS_H
18#define MINIKIN_BIDI_UTILS_H
19
20#define LOG_TAG "Minikin"
21
22#include "minikin/Layout.h"
23
24#include <memory>
25
26#include <unicode/ubidi.h>
27
28#include "minikin/Macros.h"
29#include "minikin/U16StringPiece.h"
30
31namespace minikin {
32
33struct UBiDiDeleter {
34    void operator()(UBiDi* v) { ubidi_close(v); }
35};
36
37using UBiDiUniquePtr = std::unique_ptr<UBiDi, UBiDiDeleter>;
38
39// A helper class for iterating the bidi run transitions.
40class BidiText {
41public:
42    struct RunInfo {
43        Range range;
44        bool isRtl;
45    };
46
47    BidiText(const U16StringPiece& textBuf, const Range& range, Bidi bidiFlags);
48
49    RunInfo getRunInfoAt(uint32_t runOffset) const;
50
51    class iterator {
52    public:
53        inline bool operator==(const iterator& o) const {
54            return mRunOffset == o.mRunOffset && mParent == o.mParent;
55        }
56
57        inline bool operator!=(const iterator& o) const { return !(*this == o); }
58
59        inline RunInfo operator*() const { return mParent->getRunInfoAt(mRunOffset); }
60
61        inline iterator& operator++() {
62            mRunOffset++;
63            return *this;
64        }
65
66    private:
67        friend class BidiText;
68
69        iterator(const BidiText* parent, uint32_t runOffset)
70                : mParent(parent), mRunOffset(runOffset) {}
71
72        const BidiText* mParent;
73        uint32_t mRunOffset;
74    };
75
76    inline iterator begin() const { return iterator(this, 0); }
77    inline iterator end() const { return iterator(this, mRunCount); }
78
79private:
80    UBiDiUniquePtr mBidi;  // Maybe null for single run.
81    const Range mRange;    // The range in the original buffer. Used for range check.
82    bool mIsRtl;           // The paragraph direction.
83    uint32_t mRunCount;    // The number of the bidi run in this text.
84
85    MINIKIN_PREVENT_COPY_AND_ASSIGN(BidiText);
86};
87
88}  // namespace minikin
89
90#endif  // MINIKIN_BIDI_UTILS_H
91