third_party/WebKit/Source/platform/text/Character.h

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#ifndef Character_h
#define Character_h

#include "platform/PlatformExport.h"
#include "platform/text/CharacterProperty.h"
#include "platform/text/TextDirection.h"
#include "platform/text/TextPath.h"
#include "platform/text/TextRun.h"
#include "wtf/Allocator.h"
#include "wtf/HashSet.h"
#include "wtf/text/CharacterNames.h"
#include "wtf/text/WTFString.h"

namespace blink {

class PLATFORM_EXPORT Character {
    STATIC_ONLY(Character);
public:
    static CodePath characterRangeCodePath(const LChar*, unsigned) { return SimplePath; }
    static CodePath characterRangeCodePath(const UChar*, unsigned len);

    static inline bool isInRange(UChar32 character, UChar32 lowerBound, UChar32 upperBound)
    {
        return character >= lowerBound && character <= upperBound;
    }

    static inline bool isUnicodeVariationSelector(UChar32 character)
    {
        // http://www.unicode.org/Public/UCD/latest/ucd/StandardizedVariants.html
        return isInRange(character, 0x180B, 0x180D) // MONGOLIAN FREE VARIATION SELECTOR ONE to THREE
            || isInRange(character, 0xFE00, 0xFE0F) // VARIATION SELECTOR-1 to 16
            || isInRange(character, 0xE0100, 0xE01EF); // VARIATION SELECTOR-17 to 256
    }

    static bool isCJKIdeographOrSymbol(UChar32);
    static bool isCJKIdeographOrSymbolBase(UChar32 c)
    {
        return isCJKIdeographOrSymbol(c)
            && !(U_GET_GC_MASK(c) & (U_GC_M_MASK | U_GC_LM_MASK | U_GC_SK_MASK));
    }

    static unsigned expansionOpportunityCount(const LChar*, size_t length, TextDirection, bool& isAfterExpansion, const TextJustify);
    static unsigned expansionOpportunityCount(const UChar*, size_t length, TextDirection, bool& isAfterExpansion, const TextJustify);
    static unsigned expansionOpportunityCount(const TextRun& run, bool& isAfterExpansion)
    {
        if (run.is8Bit())
            return expansionOpportunityCount(run.characters8(), run.length(), run.direction(), isAfterExpansion, run.getTextJustify());
        return expansionOpportunityCount(run.characters16(), run.length(), run.direction(), isAfterExpansion, run.getTextJustify());
    }

    static bool isUprightInMixedVertical(UChar32 character);

    // https://html.spec.whatwg.org/multipage/scripting.html#prod-potentialcustomelementname
    static bool isPotentialCustomElementNameChar(UChar32 character);

    static bool treatAsSpace(UChar32 c)
    {
        return c == spaceCharacter
            || c == tabulationCharacter
            || c == newlineCharacter
            || c == noBreakSpaceCharacter;
    }
    static bool treatAsZeroWidthSpace(UChar32 c)
    {
        return treatAsZeroWidthSpaceInComplexScript(c)
            || c == zeroWidthNonJoinerCharacter
            || c == zeroWidthJoinerCharacter;
    }
    static bool treatAsZeroWidthSpaceInComplexScript(UChar32 c)
    {
        return c < 0x20 // ASCII Control Characters
            || (c >= 0x7F && c < 0xA0) // ASCII Delete .. No-break spaceCharacter
            || c == softHyphenCharacter
            || c == zeroWidthSpaceCharacter
            || (c >= leftToRightMarkCharacter && c <= rightToLeftMarkCharacter)
            || (c >= leftToRightEmbedCharacter && c <= rightToLeftOverrideCharacter)
            || c == zeroWidthNoBreakSpaceCharacter
            || c == objectReplacementCharacter;
    }
    static bool canReceiveTextEmphasis(UChar32);

    static bool isGraphemeExtended(UChar32 c)
    {
        // http://unicode.org/reports/tr29/#Extend
        return u_hasBinaryProperty(c, UCHAR_GRAPHEME_EXTEND);
    }

    // Returns true if the character has a Emoji property.
    // See http://www.unicode.org/Public/emoji/3.0/emoji-data.txt
    static bool isEmoji(UChar32);
    // Default presentation style according to:
    // http://www.unicode.org/reports/tr51/#Presentation_Style
    static bool isEmojiTextDefault(UChar32);
    static bool isEmojiEmojiDefault(UChar32);
    static bool isEmojiModifierBase(UChar32);
    static bool isEmojiKeycapBase(UChar32);
    static bool isRegionalIndicator(UChar32);
    static bool isModifier(UChar32 c)
    {
        return c >= 0x1F3FB && c <= 0x1F3FF;
    }

    static inline UChar normalizeSpaces(UChar character)
    {

        if (treatAsSpace(character))
            return spaceCharacter;

        if (treatAsZeroWidthSpace(character))
            return zeroWidthSpaceCharacter;

        return character;
    }

    static inline bool isNormalizedCanvasSpaceCharacter(UChar32 c)
    {
        // According to specification all space characters should be replaced with 0x0020 space character.
        // http://www.whatwg.org/specs/web-apps/current-work/multipage/the-canvas-element.html#text-preparation-algorithm
        // The space characters according to specification are : U+0020, U+0009, U+000A, U+000C, and U+000D.
        // http://www.whatwg.org/specs/web-apps/current-work/multipage/common-microsyntaxes.html#space-character
        // This function returns true for 0x000B also, so that this is backward compatible.
        // Otherwise, the test LayoutTests/canvas/philip/tests/2d.text.draw.space.collapse.space.html will fail
        return c == 0x0009 || (c >= 0x000A && c <= 0x000D);
    }

    static String normalizeSpaces(const LChar*, unsigned length);
    static String normalizeSpaces(const UChar*, unsigned length);

    static bool isCommonOrInheritedScript(UChar32);
};

} // namespace blink

#endif