1/*
2 * Copyright (c) 2020-2022 Huawei Device Co., Ltd.
3 * Licensed under the Apache License, Version 2.0 (the "License");
4 * you may not use this file except in compliance with the License.
5 * You may obtain a copy of the License at
6 *
7 *     http://www.apache.org/licenses/LICENSE-2.0
8 *
9 * Unless required by applicable law or agreed to in writing, software
10 * distributed under the License is distributed on an "AS IS" BASIS,
11 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 * See the License for the specific language governing permissions and
13 * limitations under the License.
14 */
15
16/*
17 * Font cache is used for managing font bitmap.
18 * Each bitmap is contained in a chunk block which can be searched quickly in a hash-table.
19 * All the struct and memory block are force-aligned to ALIGNMENT_BYTES.
20 * To make the most frequently used memroy hot, chunk blocks are managed with an easy lru algorithm.
21 * Memory maps of font cache is shown below:
22 *
23 *  aligned bitmapCache    ─────────►┌────────────────────┐
24 *  (FONT_BITMAP_CACHE_SIZE)         │    HashTable       │
25 *                                   │    (ListHead*32)   │
26 *  UIFontAllocator::free_ ──────────┼────────────────────┼───────────► ┌──────────────┐
27 *                                   │    chunk block     │             │ struct Chunk │
28 *                                   ├────────────────────┼──────┐      ├──────────────┤
29 *                                   │    ...             │      │      │ struct Bitmap│
30 *                                   ├────────────────────┤      │      ├──────────────┤
31 *                                   │    chunk block     │      │      │  FontCache   │
32 *                                   ├────────────────────┤      │      │  (20*20*n)   │
33 *                                   │    last_chunk      │      └────► └──────────────┘
34 *                                   │    (Head only)     │
35 *                                   └────────────────────┘
36 */
37#ifndef UI_FONT_CACHE_H
38#define UI_FONT_CACHE_H
39
40#include "ui_font_allocator.h"
41#include "font/ui_font_header.h"
42
43namespace OHOS {
44class UIFontCache : public HeapBase {
45public:
46    static constexpr uint8_t FONT_CACHE_HASH_NR = 32;
47    static constexpr uint32_t FONT_CACHE_MIN_SIZE = 20 * 20;
48    struct UI_STRUCT_ALIGN ListHead {
49        ListHead* prev;
50        ListHead* next;
51    };
52    struct UI_STRUCT_ALIGN Bitmap {
53        ListHead hashHead;
54        ListHead lruHead;
55        uint32_t fontId; // bitmap font: fontId vector font: fontKey ttfId + fontsize
56        uint32_t unicode;
57        uint32_t reserve1;
58        uint32_t reserve2;
59#if defined(ENABLE_TEXT_STYLE) && ENABLE_TEXT_STYLE
60        TextStyle textStyle;
61#endif
62        uint8_t data[];
63    };
64
65    UIFontCache(uint8_t* ram, uint32_t size);
66
67    ~UIFontCache();
68
69    /* default textStyle is TEXT_STYLE_NORMAL, TextStyle textStyle = TEXT_STYLE_NORMAL */
70    uint8_t* GetSpace(uint16_t fontKey, uint32_t unicode, uint32_t size, TextStyle textStyle);
71    void PutSpace(uint8_t* addr);
72    uint8_t* GetBitmap(uint16_t fontKey, uint32_t unicode, TextStyle textStyle);
73
74private:
75    void UpdateLru(Bitmap* bitmap);
76    void ListInit(ListHead* head)
77    {
78        head->prev = head;
79        head->next = head;
80    }
81    void ListAdd(ListHead* node, ListHead* head)
82    {
83        head->next->prev = node;
84        node->next = head->next;
85        node->prev = head;
86        head->next = node;
87    }
88    void ListDel(ListHead* node)
89    {
90        node->next->prev = node->prev;
91        node->prev->next = node->next;
92    }
93
94    UIFontAllocator allocator_;
95    ListHead* hashTable_ = nullptr;
96    ListHead lruList_ = {};
97};
98} // namespace OHOS
99#endif /* UI_FONT_CACHE_H */
100