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/*
* Copyright (C) 2015 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef MINIKIN_FONT_LANGUAGE_H
#define MINIKIN_FONT_LANGUAGE_H
#include <string>
#include <vector>
#include <hb.h>
namespace android {
// Due to the limits in font fallback score calculation, we can't use anything more than 17
// languages.
const size_t FONT_LANGUAGES_LIMIT = 17;
class FontLanguages;
// FontLanguage is a compact representation of a BCP 47 language tag. It
// does not capture all possible information, only what directly affects
// font rendering.
struct FontLanguage {
public:
// Default constructor creates the unsupported language.
FontLanguage() : mScript(0ul), mLanguage(0ul), mSubScriptBits(0ul) {}
// Parse from string
FontLanguage(const char* buf, size_t length);
bool operator==(const FontLanguage other) const {
return !isUnsupported() && isEqualScript(other) && mLanguage == other.mLanguage;
}
bool operator!=(const FontLanguage other) const {
return !(*this == other);
}
bool isUnsupported() const { return mLanguage == 0ul; }
bool hasEmojiFlag() const { return mSubScriptBits & kEmojiFlag; }
bool isEqualScript(const FontLanguage& other) const;
// Returns true if this script supports the given script. For example, ja-Jpan supports Hira,
// ja-Hira doesn't support Jpan.
bool supportsHbScript(hb_script_t script) const;
std::string getString() const;
// Calculates a matching score. This score represents how well the input languages cover this
// language. The maximum score in the language list is returned.
// 0 = no match, 1 = script match, 2 = script and primary language match.
int calcScoreFor(const FontLanguages& supported) const;
uint64_t getIdentifier() const { return (uint64_t)mScript << 32 | (uint64_t)mLanguage; }
private:
friend class FontLanguages; // for FontLanguages constructor
// ISO 15924 compliant script code. The 4 chars script code are packed into a 32 bit integer.
uint32_t mScript;
// ISO 639-1 or ISO 639-2 compliant language code.
// The two or three letter language code is packed into 32 bit integer.
// mLanguage = 0 means the FontLanguage is unsupported.
uint32_t mLanguage;
// For faster comparing, use 8 bits for specific scripts.
static const uint8_t kBopomofoFlag = 1u;
static const uint8_t kEmojiFlag = 1u << 1;
static const uint8_t kHanFlag = 1u << 2;
static const uint8_t kHangulFlag = 1u << 3;
static const uint8_t kHiraganaFlag = 1u << 4;
static const uint8_t kKatakanaFlag = 1u << 5;
static const uint8_t kSimplifiedChineseFlag = 1u << 6;
static const uint8_t kTraditionalChineseFlag = 1u << 7;
uint8_t mSubScriptBits;
static uint8_t scriptToSubScriptBits(uint32_t script);
// Returns true if the provide subscript bits has the requested subscript bits.
// Note that this function returns false if the requested subscript bits are empty.
static bool supportsScript(uint8_t providedBits, uint8_t requestedBits);
};
// An immutable list of languages.
class FontLanguages {
public:
FontLanguages(std::vector<FontLanguage>&& languages);
FontLanguages() : mUnionOfSubScriptBits(0), mIsAllTheSameLanguage(false) {}
FontLanguages(FontLanguages&&) = default;
size_t size() const { return mLanguages.size(); }
bool empty() const { return mLanguages.empty(); }
const FontLanguage& operator[] (size_t n) const { return mLanguages[n]; }
private:
friend struct FontLanguage; // for calcScoreFor
std::vector<FontLanguage> mLanguages;
uint8_t mUnionOfSubScriptBits;
bool mIsAllTheSameLanguage;
uint8_t getUnionOfSubScriptBits() const { return mUnionOfSubScriptBits; }
bool isAllTheSameLanguage() const { return mIsAllTheSameLanguage; }
// Do not copy and assign.
FontLanguages(const FontLanguages&) = delete;
void operator=(const FontLanguages&) = delete;
};
} // namespace android
#endif // MINIKIN_FONT_LANGUAGE_H
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