diff --git a/packages/rtl-unicode/src/inc/graphemebreakproperty.pp b/packages/rtl-unicode/src/inc/graphemebreakproperty.pp index 266bfb3ad5..f097f74db2 100644 --- a/packages/rtl-unicode/src/inc/graphemebreakproperty.pp +++ b/packages/rtl-unicode/src/inc/graphemebreakproperty.pp @@ -55,6 +55,29 @@ type gbpGlue_After_Zwj, gbpE_Base_GAZ); + { TUnicodeStringExtendedGraphemeClustersEnumerator } + + TUnicodeStringExtendedGraphemeClustersEnumerator = class + private + FStr: UnicodeString; + FCurrentIndexStart: SizeInt; + FCurrentIndexEnd: SizeInt; + FNextIndexEnd: SizeInt; + FNextGBP: TGraphemeBreakProperty; + FNextCodePoint: UCS4Char; + FCurrentGBP: TGraphemeBreakProperty; + FCurrentCodePoint: UCS4Char; + FRI_Sequence_Length: Integer; + FE_Base_EBG_Extend_Sequence: Boolean; + function GetCurrent: UnicodeString; + procedure FetchNextChar; + public + constructor Create(const S: UnicodeString); + function GetEnumerator: TUnicodeStringExtendedGraphemeClustersEnumerator; + function MoveNext: Boolean; + property Current: UnicodeString read GetCurrent; + end; + function GetGraphemeBreakProperty(Ch: UCS4Char): TGraphemeBreakProperty; implementation @@ -64,4 +87,94 @@ begin {$I graphemebreakproperty_code.inc} end; +{ TUnicodeStringExtendedGraphemeClustersEnumerator } + +function TUnicodeStringExtendedGraphemeClustersEnumerator.GetCurrent: UnicodeString; +begin + Result := Copy(FStr, FCurrentIndexStart, FCurrentIndexEnd - FCurrentIndexStart + 1); +end; + +procedure TUnicodeStringExtendedGraphemeClustersEnumerator.FetchNextChar; +begin + Inc(FNextIndexEnd); + if FNextIndexEnd <= Length(FStr) then + begin + FNextCodePoint := Ord(FStr[FNextIndexEnd]); + { high surrogate, followed by low surrogate? } + if (FNextCodePoint >= $D800) and (FNextCodePoint <= $DBFF) and ((FNextIndexEnd + 1) <= Length(FStr)) and + (Ord(FStr[FNextIndexEnd + 1]) >= $DC00) and (Ord(FStr[FNextIndexEnd + 1]) <= $DFFF) then + begin + Inc(FNextIndexEnd); + FNextCodePoint := $10000 + (((FNextCodePoint - $D800) shl 10) or (Ord(FStr[FNextIndexEnd]) - $DC00)); + end; + end + else + FNextCodePoint := 0; + FNextGBP := GetGraphemeBreakProperty(FNextCodePoint); +end; + +constructor TUnicodeStringExtendedGraphemeClustersEnumerator.Create(const S: UnicodeString); +begin + FStr := S; + FCurrentIndexStart := 0; + FCurrentIndexEnd := 0; + FNextIndexEnd := 0; + FRI_Sequence_Length := 0; + FE_Base_EBG_Extend_Sequence := False; + FetchNextChar; +end; + +function TUnicodeStringExtendedGraphemeClustersEnumerator.GetEnumerator: TUnicodeStringExtendedGraphemeClustersEnumerator; +begin + Result := Self; +end; + +function TUnicodeStringExtendedGraphemeClustersEnumerator.MoveNext: Boolean; +begin + FCurrentIndexStart := FCurrentIndexEnd + 1; + if FCurrentIndexStart > Length(FStr) then + Exit(false); + repeat + FCurrentGBP := FNextGBP; + FCurrentCodePoint := FNextCodePoint; + FCurrentIndexEnd := FNextIndexEnd; + if FCurrentGBP = gpbRegional_Indicator then + Inc(FRI_Sequence_Length) + else + FRI_Sequence_Length := 0; + FE_Base_EBG_Extend_Sequence := (FCurrentGBP in [gbpE_Base, gbpE_Base_GAZ]) or (FE_Base_EBG_Extend_Sequence and (FCurrentGBP = gbpExtend)); + FetchNextChar; + if FNextIndexEnd > Length(FStr) then + Exit(True); + + { Do not break between a CR and LF. Otherwise, break before and after controls. } + if (FCurrentGBP = gbpCR) and (FNextGBP = gbpLF) then + continue + else if (FCurrentGBP in [gbpControl, gbpCR, gbpLF]) or (FNextGBP in [gbpControl, gbpCR, gbpLF]) then + Exit(True) + { Do not break Hangul syllable sequences. } + else if ((FCurrentGBP = gbpL) and (FNextGBP in [gbpL, gbpV, gbpLV, gbpLVT])) or + ((FCurrentGBP in [gbpLV, gbpV]) and (FNextGBP in [gbpV, gbpT])) or + ((FCurrentGBP in [gbpLVT, gbpT]) and (FNextGBP = gbpT)) then + continue + { Do not break before extending characters or ZWJ. } + else if FNextGBP in [gbpExtend, gbpZWJ] then + continue + { Only for extended grapheme clusters: + Do not break before SpacingMarks, or after Prepend characters. } + else if (FCurrentGBP = gbpPrepend) or (FNextGBP = gbpSpacingMark) then + continue + { Do not break within emoji modifier sequences or emoji zwj sequences. } + else if ((FCurrentGBP = gbpZWJ) and (FNextGBP in [gbpGlue_After_Zwj, gbpE_Base_GAZ])) or + (FE_Base_EBG_Extend_Sequence and (FNextGBP = gbpE_Modifier)) then + continue + { Do not break within emoji flag sequences. That is, do not break between regional indicator (RI) symbols if there is an odd number of RI characters before the break point. } + else if (FCurrentGBP = gpbRegional_Indicator) and (FNextGBP = gpbRegional_Indicator) and Odd(FRI_Sequence_Length) then + continue + { Otherwise, break everywhere. } + else + Exit(True); + until False; +end; + end.