1 /* 2 * Copyright (C) 2015 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_FONT_LANGUAGE_H 18 #define MINIKIN_FONT_LANGUAGE_H 19 20 #include <string> 21 #include <vector> 22 23 #include <hb.h> 24 25 namespace android { 26 27 // Due to the limits in font fallback score calculation, we can't use anything more than 17 28 // languages. 29 const size_t FONT_LANGUAGES_LIMIT = 17; 30 class FontLanguages; 31 32 // FontLanguage is a compact representation of a BCP 47 language tag. It 33 // does not capture all possible information, only what directly affects 34 // font rendering. 35 struct FontLanguage { 36 public: 37 // Default constructor creates the unsupported language. FontLanguageFontLanguage38 FontLanguage() : mScript(0ul), mLanguage(0ul), mSubScriptBits(0ul) {} 39 40 // Parse from string 41 FontLanguage(const char* buf, size_t length); 42 43 bool operator==(const FontLanguage other) const { 44 return !isUnsupported() && isEqualScript(other) && mLanguage == other.mLanguage; 45 } 46 47 bool operator!=(const FontLanguage other) const { 48 return !(*this == other); 49 } 50 isUnsupportedFontLanguage51 bool isUnsupported() const { return mLanguage == 0ul; } hasEmojiFlagFontLanguage52 bool hasEmojiFlag() const { return mSubScriptBits & kEmojiFlag; } 53 54 bool isEqualScript(const FontLanguage& other) const; 55 56 // Returns true if this script supports the given script. For example, ja-Jpan supports Hira, 57 // ja-Hira doesn't support Jpan. 58 bool supportsHbScript(hb_script_t script) const; 59 60 std::string getString() const; 61 62 // Calculates a matching score. This score represents how well the input languages cover this 63 // language. The maximum score in the language list is returned. 64 // 0 = no match, 1 = script match, 2 = script and primary language match. 65 int calcScoreFor(const FontLanguages& supported) const; 66 getIdentifierFontLanguage67 uint64_t getIdentifier() const { return (uint64_t)mScript << 32 | (uint64_t)mLanguage; } 68 69 private: 70 friend class FontLanguages; // for FontLanguages constructor 71 72 // ISO 15924 compliant script code. The 4 chars script code are packed into a 32 bit integer. 73 uint32_t mScript; 74 75 // ISO 639-1 or ISO 639-2 compliant language code. 76 // The two or three letter language code is packed into 32 bit integer. 77 // mLanguage = 0 means the FontLanguage is unsupported. 78 uint32_t mLanguage; 79 80 // For faster comparing, use 8 bits for specific scripts. 81 static const uint8_t kBopomofoFlag = 1u; 82 static const uint8_t kEmojiFlag = 1u << 1; 83 static const uint8_t kHanFlag = 1u << 2; 84 static const uint8_t kHangulFlag = 1u << 3; 85 static const uint8_t kHiraganaFlag = 1u << 4; 86 static const uint8_t kKatakanaFlag = 1u << 5; 87 static const uint8_t kSimplifiedChineseFlag = 1u << 6; 88 static const uint8_t kTraditionalChineseFlag = 1u << 7; 89 uint8_t mSubScriptBits; 90 91 static uint8_t scriptToSubScriptBits(uint32_t script); 92 93 // Returns true if the provide subscript bits has the requested subscript bits. 94 // Note that this function returns false if the requested subscript bits are empty. 95 static bool supportsScript(uint8_t providedBits, uint8_t requestedBits); 96 }; 97 98 // An immutable list of languages. 99 class FontLanguages { 100 public: 101 FontLanguages(std::vector<FontLanguage>&& languages); FontLanguages()102 FontLanguages() : mUnionOfSubScriptBits(0), mIsAllTheSameLanguage(false) {} 103 FontLanguages(FontLanguages&&) = default; 104 size()105 size_t size() const { return mLanguages.size(); } empty()106 bool empty() const { return mLanguages.empty(); } 107 const FontLanguage& operator[] (size_t n) const { return mLanguages[n]; } 108 109 private: 110 friend struct FontLanguage; // for calcScoreFor 111 112 std::vector<FontLanguage> mLanguages; 113 uint8_t mUnionOfSubScriptBits; 114 bool mIsAllTheSameLanguage; 115 getUnionOfSubScriptBits()116 uint8_t getUnionOfSubScriptBits() const { return mUnionOfSubScriptBits; } isAllTheSameLanguage()117 bool isAllTheSameLanguage() const { return mIsAllTheSameLanguage; } 118 119 // Do not copy and assign. 120 FontLanguages(const FontLanguages&) = delete; 121 void operator=(const FontLanguages&) = delete; 122 }; 123 124 } // namespace android 125 126 #endif // MINIKIN_FONT_LANGUAGE_H 127