modules/skshaper/src/SkUnicode.h

/*
 * Copyright 2020 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */
#ifndef SkUnicode_DEFINED
#define SkUnicode_DEFINED

#include "include/core/SkTypes.h"
#include "src/core/SkSpan.h"
#include <vector>

#if !defined(SKUNICODE_IMPLEMENTATION)
    #define SKUNICODE_IMPLEMENTATION 0
#endif

#if !defined(SKUNICODE_API)
    #if defined(SKSHAPER_DLL)
        #if defined(_MSC_VER)
            #if SKUNICODE_IMPLEMENTATION
                #define SKUNICODE_API __declspec(dllexport)
            #else
                #define SKUNICODE_API __declspec(dllimport)
            #endif
        #else
            #define SKUNICODE_API __attribute__((visibility("default")))
        #endif
    #else
        #define SKUNICODE_API
    #endif
#endif

enum class UtfFormat {
    kUTF8,
    kUTF16
};
// Bidi
typedef size_t Position;
typedef uint8_t BidiLevel;
enum class Direction {
    kLTR,
    kRTL,
};
struct BidiRegion {
    BidiRegion(Position start, Position end, BidiLevel level)
      : start(start), end(end), level(level) { }
    Position start;
    Position end;
    BidiLevel level;
};
// LineBreaks
enum class LineBreakType {
    kSoftLineBreak,
    kHardLineBreak
};
struct LineBreakBefore {
    LineBreakBefore(Position pos, LineBreakType breakType)
      : pos(pos), breakType(breakType) { }
    Position pos;
    LineBreakType breakType;
};
// Other breaks
enum class UBreakType {
    kWords,
    kGraphemes,
    kLines
};
struct Range {
    Position start;
    Position end;
};

class SKUNICODE_API SkBidiIterator {
public:
    typedef int32_t Position;
    typedef uint8_t Level;
    struct Region {
        Region(Position start, Position end, Level level)
            : start(start), end(end), level(level) { }
        Position start;
        Position end;
        Level level;
    };
    enum Direction {
        kLTR,
        kRTL,
    };
    virtual ~SkBidiIterator() {}
    virtual Position getLength() = 0;
    virtual Level getLevelAt(Position) = 0;
    static void ReorderVisual(const Level runLevels[], int levelsCount, int32_t logicalFromVisual[]);
};

class SKUNICODE_API SkUnicode {
    public:
        typedef uint32_t ScriptID;
        typedef uint32_t CombiningClass;
        typedef uint32_t GeneralCategory;
        virtual ~SkUnicode() = default;

        // Iterators (used in SkShaper)
        virtual std::unique_ptr<SkBidiIterator> makeBidiIterator
            (const uint16_t text[], int count, SkBidiIterator::Direction) = 0;
        virtual std::unique_ptr<SkBidiIterator> makeBidiIterator
            (const char text[], int count, SkBidiIterator::Direction) = 0;

        // High level methods (that we actually use somewhere=SkParagraph)
        virtual bool getBidiRegions
               (const char utf8[], int utf8Units, Direction dir, std::vector<BidiRegion>* results) = 0;
        virtual bool getLineBreaks
               (const char utf8[], int utf8Units, std::vector<LineBreakBefore>* results) = 0;
        virtual bool getWords
               (const char utf8[], int utf8Units, std::vector<Position>* results) = 0;
        virtual bool getGraphemes
               (const char utf8[], int utf8Units, std::vector<Position>* results) = 0;
        virtual bool getWhitespaces
               (const char utf8[], int utf8Units, std::vector<Position>* results) = 0;

        virtual void reorderVisual(const BidiLevel runLevels[], int levelsCount, int32_t logicalFromVisual[]) = 0;

        static std::unique_ptr<SkUnicode> Make();
};

#endif // SkUnicode_DEFINED