[fpc-devel] sysstr patch once more

[petr.kristan at epos.cz]

Hi.

sysstr.inc r10846 does not include my patch, which solves problem when both strings
are empty and differs after null character. Then I'am sending it again merged against trunk.

Here is testcase:

program comp;
uses
   SysUtils;
var
  a, b: array[0..1] of char;
begin
  a[0] := #0; a[1] := #1; //Empty string
  b[0] := #0; b[1] := #0; //Empty string with different char after end
  writeln(AnsiStrComp(a, b)); //should be zero because a=b
  writeln(AnsiStrIComp(a, b)); /should be zero because a=b
end.

And here is patch. Construction with "repeat" overflows strings boundary in the first cycle, 
"while" solves this problem. The same construction is used in GenericAnsiCompareText.

Index: rtl/objpas/sysutils/sysstr.inc
===================================================================
--- rtl/objpas/sysutils/sysstr.inc      (revision 10891)
+++ rtl/objpas/sysutils/sysstr.inc      (working copy)
@@ -307,11 +307,11 @@
       Result:=1;
       exit;
     end;
-  Repeat
+  While (Result=0) and (S1^<>#0) and (S2^<>#0) do begin
     Result:=Ord(S1^)-Ord(S2^); //!! Must be replaced by ansi characters !!
     Inc(S1);
     Inc(S2);
-  Until (Result<>0) or (S1^=#0) or (S2^=#0);
+  end;  
   if (Result=0) and (S1^<>S2^) then // loop ended because exactly one has #0
     if S1^=#0 then // shorter string is smaller
       result:=-1
@@ -335,11 +335,11 @@
     Result:=1;
     exit;
     end;
-  Repeat
+  While (Result=0) and (S1^<>#0) and (S2^<>#0) do begin
     Result:=Ord(LowerCaseTable[Ord(S1[0])])-Ord(LowerCaseTable[Ord(S2[0])]); //!! Must be replaced by ansi characters !!
     Inc(S1);
     Inc(S2);
-  Until (Result<>0) or ((S1[0]=#0) or (S2[0]=#0));
+  end;
   if (Result=0) and (s1[0]<>s2[0]) then //length(s1)<>length(s2)
     if s1[0]=#0 then
       Result:=-1 //s1 shorter than s2
 
-- 
Ing. Petr Kristan
.
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