+ added support for logical/visual cursor mapping

rtl/objpas/utf8bidi.pp

@@ -10,110 +10,326 @@ interface
 
 type
   TUCS32Char = Cardinal;
-  TUTF8Char = String[3];
-  TUTF8Str = UTF8String;
+  TUCS16Char = Word;
+  TUTF8Char = String[4];
+  TUTF8String = UTF8String;
   TDirection=(
     drNONE,
     drRTL,
     drLTR
   );
 
-function UnicodeToUtf8(aChar:TUCS32Char):TUTF8Char;
-function UnicodeToUtf8(aChar:WideChar):TUTF8Char;
-procedure insert(CharToInsert:TUTF8Char; var uString:TUTF8Str; var CursorPos:Integer);
+{****************************Conversion routines*******************************}
+{Converts an UCS 16/32 bits charcater to UTF8 character}
+function UnicodeToUTF8(aChar:TUCS32Char):TUTF8Char;
+{Converts a wide char UCS 16 bits chcarcter to UTF8 character}
+function UnicodeToUTF8(aChar:WideChar):TUTF8Char;
+{Converts an UTF8 character to UCS 32 bits character}
+function UTF8ToUnicode(const UTF8Char:TUTF8Char):TUCS32Char;
+{Converts an UTF8 string to a double byte string}
+function UTF8ToDoubleByteString(const UTF8Str:TUTF8String):String;
+function UTF8ToDoubleByte(UTF8Str:PChar; Len:Cardinal; DBStr:PByte):Cardinal;
+{****************************Logical aspects***********************************}
+{Returns the number of logical characters}
+function LLength(const UTF8Str:TUTF8String):Cardinal;
+{Converts visual position to logical position}
+function LPos(const UTF8Str:TUTF8String; vp:Cardinal; pDir:TDirection):Cardinal;
+{Returns character at a given logical position according to paragraph direction}
+function LCharOf(UTF8Str:TUTF8String; lp:Cardinal):TUTF8Char;
+{****************************Visual aspects************************************}
+{Returns the number of visual characters}
+function VLength(const UTF8Str:TUTF8String):Cardinal;
+function VLength(p: PChar; Count:Cardinal):Cardinal;
+{Converts a logical position to a visual position}
+function VPos(const UTF8Str:TUTF8String; lp:Cardinal; pDir, cDir:TDirection):Cardinal;
+function VPos(UTF8Char:PChar; Len:integer; BytePos:integer):Cardinal;
+{Returns character at a given visual position according to paragraph direction}
+function VCharOf(UTF8Str:TUTF8String; vp:Cardinal; dir:TDirection):TUTF8Char;
 
 implementation
 
-function UnicodeToUtf8(aChar:TUCS32Char):TUTF8Char;
+function ComputeCharLength(p:PChar):Cardinal;
+begin
+  if ord(p^)<%11000000
+  then
+{regular single byte character (#0 is a normal char, this is UTF8Charascal ;)}
+    Result:=1
+  else if ((ord(p^) and %11100000) = %11000000)
+  then
+    if (ord(p[1]) and %11000000) = %10000000 then
+      Result:=2
+    else
+      Result:=1
+  else if ((ord(p^) and %11110000) = %11100000)
+  then
+    if ((ord(p[1]) and %11000000) = %10000000)
+      and ((ord(p[2]) and %11000000) = %10000000)
+    then
+      Result:=3
+    else
+        Result:=1
+  else if ((ord(p^) and %11111000) = %11110000)
+  then
+    if ((ord(p[1]) and %11000000) = %10000000)
+    and ((ord(p[2]) and %11000000) = %10000000)
+    and ((ord(p[3]) and %11000000) = %10000000)
+    then
+      Result:=4
+    else
+      Result:=1
+  else
+    Result:=1
+end;
+{****************************Conversion routines*******************************}
+function UnicodeToUTF8(aChar:TUCS32Char):TUTF8Char;
 begin
   case aChar of
     0..$7f:
       begin
         Result[1]:=char(aChar);
-        SetLength(Result,1);
+        SetLength(UnicodeToUTF8,1);
       end;
     $80..$7ff:
       begin
         Result[1]:=char($c0 or (aChar shr 6));
         Result[2]:=char($80 or (aChar and $3f));
-        SetLength(Result,2);
+        SetLength(UnicodeToUTF8,2);
       end;
-    else
+    $800..$ffff:
       begin
+        SetLength(Result,3);
         Result[1]:=char($e0 or (aChar shr 12));
-        Result[2]:=char($80 or ((aChar shr 6)and $3f));
+        Result[2]:=char($80 or ((aChar shr 6) and $3f));
         Result[3]:=char($80 or (aChar and $3f));
-        SetLength(Result,3);
       end;
+    $10000..$1fffff:
+      begin
+        SetLength(UnicodeToUTF8,4);
+        Result[1]:=char($f0 or (aChar shr 18));
+        Result[2]:=char($80 or ((aChar shr 12) and $3f));
+        Result[3]:=char($80 or ((aChar shr 6) and $3f));
+        Result[4]:=char($80 or (aChar and $3f));
+      end;
+  else
+    SetLength(UnicodeToUTF8, 0);
   end;
 end;
 
-function UnicodeToUtf8(aChar:WideChar):TUTF8Char;
+function UnicodeToUTF8(aChar:WideChar):TUTF8Char;
 begin
-  UnicodeToUtf8(Word(aChar));
+  Result := UnicodeToUTF8(Word(aChar));
 end;
 
-procedure insert(CharToInsert:TUTF8Char; var uString:TUTF8Str; var CursorPos:Integer);
+function UTF8ToUnicode(const UTF8Char:TUTF8Char):TUCS32Char;
+begin
+  case ComputeCharLength(@UTF8Char[1]) of
+    1:{regular single byte character (#0 is a normal char, this is UTF8Charascal ;)}
+      Result := ord(UTF8Char[1]);
+    2:
+      Result := ((ord(UTF8Char[1]) and %00011111) shl 6)
+                or (ord(UTF8Char[2]) and %00111111);
+    3:
+      Result := ((ord(UTF8Char[1]) and %00011111) shl 12)
+                or ((ord(UTF8Char[1]) and %00111111) shl 6)
+                or (ord(UTF8Char[2]) and %00111111);
+    4:
+      Result := ((ord(UTF8Char[1]) and %00011111) shl 18)
+                or ((ord(UTF8Char[2]) and %00111111) shl 12)
+                or ((ord(UTF8Char[3]) and %00111111) shl 6)
+                or (ord(UTF8Char[4]) and %00111111);
+  else
+    Result := $FFFFFFFF;
+  end
+end;
+
+function UTF8ToDoubleByteString(const UTF8Str: TUTF8String): string;
+var
+  Len: Integer;
+begin
+  Len:=VLength(UTF8Str);
+  SetLength(Result,Len*2);
+  if Len=0 then exit;
+  UTF8ToDoubleByte(PChar(UTF8Str),length(UTF8Str),PByte(Result));
+end;
+
+function UTF8ToDoubleByte(UTF8Str: PChar; Len:Cardinal; DBStr: PByte):Cardinal;
+var
+  SrcPos: PChar;
+  CharLen: LongInt;
+  DestPos: PByte;
+  u: Cardinal;
+begin
+  SrcPos:=UTF8Str;
+  DestPos:=DBStr;
+  Result:=0;
+  while Len>0 do begin
+    u:=UTF8ToUnicode(SrcPos);
+    DestPos^:=byte((u shr 8) and $ff);
+    inc(DestPos);
+    DestPos^:=byte(u and $ff);
+    inc(DestPos);
+    inc(SrcPos,CharLen);
+    dec(Len,CharLen);
+    inc(Result);
+  end;
+end;
+{****************************Logical aspects***********************************}
+function LLength(const UTF8Str:TUTF8String):Cardinal;
+begin
+  Result := Length(UTF8Str);
+end;
+
+function LPos(const UTF8Str:TUTF8String; vp:Cardinal; pDir:TDirection):Cardinal;
 var
 {At beginning of the line we don't know which direction, thus the first
  character usually decides of paragrph direction}
-  dir:TDirection;
-  LeftCursorPos, RightCursorPos, InsertPos:Integer;
+  LeftCursorPos, RightCursorPos:Integer;
   uLen:Integer;
 begin
-  dir := drNONE;
-  uLen := Length(uString);
+  uLen := Length(UTF8Str);
   LeftCursorPos := 1;
   RightCursorPos := 1;
-  InsertPos := 1;
+  Result := 1;
   if(uLen > 0) then
     repeat
-      case uString[InsertPos] of
+      case UTF8Str[Result] of
         #32,'{','}','/'://Does not change direction, this is a neutral character;
           begin
-            if(dir = drLTR) then
+            if(pDir = drLTR) then
               Inc(RightCursorPos);
           end;
         #$d8,#$d9://Arabic
           begin
-            dir := drRTL;
-            Inc(InsertPos);//Consume control character
+            pDir := drRTL;
+            Inc(Result);//Consume control character
           end;
       else //Latin
         begin
-          dir := drLTR;
+          pDir := drLTR;
           RightCursorPos := LeftCursorPos + 1;
         end;
       end;
       Inc(LeftCursorPos);
-      Inc(InsertPos);
-    until(InsertPos > uLen) or
-         ((dir = drLTR) and (LeftCursorPos > CursorPos)) or
-         ((dir = drRTL) and (RightCursorPos > CursorPos));
-//WriteLn('uLen=',uLen,' InsertPos=',InsertPos,' CursorPos=',CursorPos,' LeftCursorPos=',LeftCursorPos,' RightCursorPos=',RightCursorPos);
-  if(InsertPos > uLen)
+      Inc(Result);
+    until(Result > uLen) or
+         ((pDir = drLTR) and (LeftCursorPos > vp)) or
+         ((pDir = drRTL) and (RightCursorPos > vp));
+//WriteLn('uLen=',uLen,' Result=',Result,' CursorPos=',CursorPos,' LeftCursorPos=',LeftCursorPos,' RightCursorPos=',RightCursorPos);
+  if(Result > uLen)
   then begin
-    if(CursorPos > LeftCursorPos) then begin
-      Inc(InsertPos, CursorPos - LeftCursorPos);
-      LeftCursorPos := CursorPos;
+    if(vp > LeftCursorPos) then begin
+      Inc(Result, vp - LeftCursorPos);
+      LeftCursorPos := vp;
     end;
     Inc(LeftCursorPos);
-    if(CursorPos > RightCursorPos) then
-      if(dir = drLTR) then
-        RightCursorPos := CursorPos;
-    uString := uString  + StringOfChar(' ', InsertPos - uLen);
+    if(vp > RightCursorPos) then
+      if(pDir = drLTR) then
+        RightCursorPos := vp;
   end;
 //WriteLn('CursorPos=',CursorPos,' LeftCursorPos=',LeftCursorPos,' RightCursorPos=',RightCursorPos);
-  System.insert(CharToInsert, uString,InsertPos);
-  case CharToInsert[1] of
+  Result := Result;
+end;
+
+function LCharOf(UTF8Str:TUTF8String; lp:Cardinal):TUTF8Char;
+begin
+  while(lp > 0) and (UTF8Str[lp] > #128) do
+    Dec(lp);
+  if lp = 0
+  then
+    Exit('');
+  Move(Result, UTF8Str[lp], SizeOf(Result));
+  SetLength(Result, ComputeCharLength(@Result[1]));
+end;
+{****************************Visual aspects************************************}
+function VLength(const UTF8Str:TUTF8String):Cardinal;
+begin
+  Result := VLength(PChar(UTF8Str),LLength(UTF8Str));
+end;
+
+function VLength(p:PChar; Count:Cardinal):Cardinal;
+var
+  CharLen: LongInt;
+begin
+  VLength:=0;
+  while (Count>0) do begin
+    inc(Result);
+    CharLen:=ComputeCharLength(p);
+    inc(p,CharLen);
+    dec(Count,CharLen);
+  end;
+end;
+
+function VPos(const UTF8Str:TUTF8String; lp:Cardinal; pDir, cDir:TDirection):Cardinal;
+var
+{At beginning of the line we don't know which direction, thus the first
+ character usually decides of paragrph direction}
+  LeftCursorPos, RightCursorPos:Integer;
+  uLen:Integer;
+begin
+  uLen := Length(UTF8Str);
+  LeftCursorPos := 1;
+  RightCursorPos := 1;
+  Result := 1;
+  if(uLen > 0) then
+    repeat
+      case UTF8Str[Result] of
+        #32,'{','}','/'://Does not change direction, this is a neutral character;
+          begin
+            if(pDir = drLTR) then
+              Inc(RightCursorPos);
+          end;
+        #$d8,#$d9://Arabic
+          begin
+            pDir := drRTL;
+            Inc(Result);//Consume control character
+          end;
+      else //Latin
+        begin
+          pDir := drLTR;
+          RightCursorPos := LeftCursorPos + 1;
+        end;
+      end;
+      Inc(LeftCursorPos);
+      Inc(Result);
+    until(Result > uLen) or
+         ((pDir = drLTR) and (LeftCursorPos > lp)) or
+         ((pDir = drRTL) and (RightCursorPos > lp));
+//WriteLn('uLen=',uLen,' Result=',Result,' CursorPos=',CursorPos,' LeftCursorPos=',LeftCursorPos,' RightCursorPos=',RightCursorPos);
+  if(Result > uLen)
+  then begin
+    if(lp > LeftCursorPos) then begin
+      Inc(Result, lp - LeftCursorPos);
+      LeftCursorPos := lp;
+    end;
+    Inc(LeftCursorPos);
+    if(lp > RightCursorPos) then
+      if(pDir = drLTR) then
+        RightCursorPos := lp;
+  end;
+//WriteLn('CursorPos=',CursorPos,' LeftCursorPos=',LeftCursorPos,' RightCursorPos=',RightCursorPos);
+  Result := Result;
+{  case dir of
     #32:
       CursorPos := LeftCursorPos;
     #$d8,#$d9:
       CursorPos := RightCursorPos;
     else
       CursorPos := LeftCursorPos;
-  end;
-//WriteLn('InsertPos=',InsertPos,' New CursorPos=',CursorPos);
+  end;}
+//WriteLn('Result=',Result,' New CursorPos=',CursorPos);
 end;
+
+function VPos(UTF8Char:PChar; Len:integer; BytePos:integer):Cardinal;
+begin
+end;
+
+
+function VCharOf(UTF8Str:TUTF8String; vp:Cardinal; dir:TDirection):TUTF8Char;
+var
+  CharLen: LongInt;
+begin
+  Result:=LCharOf(UTF8Str,LPos(UTF8Str, vp, dir));
+end;
+
 end.