MG: started diffpatch unit

git-svn-id: trunk@1813 -

.gitattributes

@@ -154,6 +154,7 @@ ide/compileroptions.pp svneol=native#text/pascal
 ide/compreg.pp svneol=native#text/pascal
 ide/customformeditor.pp svneol=native#text/pascal
 ide/debugmanager.pas svneol=native#text/pascal
+ide/diffpatch.pas svneol=native#text/pascal
 ide/diskdiffsdialog.pas svneol=native#text/pascal
 ide/editdefinetree.pas svneol=native#text/pascal
 ide/editoroptions.lrs svneol=native#text/pascal

ide/diffpatch.pas

@@ -0,0 +1,163 @@
+{  $Id$  }
+{
+ /***************************************************************************
+   diffpatch.pas - functions to extract differences between texts
+                   (diffs, patches) and apply them (patching).
+
+ ***************************************************************************/
+
+ ***************************************************************************
+ *                                                                         *
+ *   This source is free software; you can redistribute it and/or modify   *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ *   This code is distributed in the hope that it will be useful, but      *
+ *   WITHOUT ANY WARRANTY; without even the implied warranty of            *
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU     *
+ *   General Public License for more details.                              *
+ *                                                                         *
+ *   A copy of the GNU General Public License is available on the World    *
+ *   Wide Web at <http://www.gnu.org/copyleft/gpl.html>. You can also      *
+ *   obtain it by writing to the Free Software Foundation,                 *
+ *   Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.        *
+ *                                                                         *
+ ***************************************************************************
+
+  Author: Mattias Gaertner
+
+}
+unit DiffPatch;
+
+{$mode objfpc}{$H+}
+
+interface
+
+uses
+  Classes, SysUtils; 
+
+type
+  TTextDiffFlag = (
+    tdfIgnoreSpaceCharAmount,
+    tdfIgnoreSpaceChars,
+    tdfIgnoreEmptyLineChanges,
+    tdfIgnoreCase
+  );
+  TTextDiffFlags = set of TTextDiffFlag;
+
+procedure CreateTextDiff(Text1, Text2, DiffText: TStrings;
+  Flags: TTextDiffFlags);
+
+
+implementation
+
+
+const
+  IsSpaceChars, UpperCaseChars: array[char] of boolean;
+
+
+function IsEmptyLine(const s: string; Flags: TTextDiffFlags): boolean;
+var i: integer;
+begin
+  if ([tdfIgnoreSpaceCharAmount,tdfIgnoreSpaceChars]*Flags)<>[] then begin
+    Result:=true;
+    for i:=1 to length(s) do begin
+      if not IsSpaceChars[s[i]] then begin
+        Result:=false;
+        exit;
+      end;
+    end;
+  end else begin
+    Result:=(s='');
+  end;
+end;
+
+function LinesAreEqual(const Line1, Line2: string; Flags: TTextDiffFlags
+  ): boolean;
+var Pos1, Pos2, Len1, Len2: integer;
+begin
+  if ([tdfIgnoreSpaceCharAmount,tdfIgnoreSpaceChars]*Flags)<>[] then begin
+    // completely ignore space chars
+    Result:=true;
+    Len1:=length(Line1);
+    Len2:=length(Line2);
+    Pos1:=1;
+    Pos2:=1;
+    while (Pos1<=Len1) and (Pos2<=Len2) do begin
+      if ((not (tdfIgnoreCase in Flags))
+        and (Line1[Pos1]=Line2[Pos2]))
+      or ((tdfIgnoreCase in Flags)
+        and (UpperCaseChars[Line1[Pos1]]=UpperCaseChars[Line2[Pos2]]))
+      then begin
+        // both chars are the same
+        inc(Pos1);
+        inc(Pos2);
+        continue;
+      end else begin
+        // there is a difference
+        if (tdfIgnoreSpaceChars in Flags) then begin
+          if IsSpaceChars[Line1[Pos1]]
+          or IsSpaceChars[Line2[Pos2]]
+          then begin
+            // skip spaces
+            while (Pos1<=Len1) and IsSpaceChars[Line1[Pos1]] do inc(Pos1);
+            while (Pos2<=Len2) and IsSpaceChars[Line2[Pos2]] do inc(Pos2);
+          end else begin
+            Result:=false;
+          end;
+        end else begin
+          xxx
+        end;
+      end;
+    end;
+  end else begin
+    if (tdfIgnoreCase in Flags) then begin
+      Result:=(AnsiCompareText(Line1,Line2)=0);
+    end else begin
+      Result:=(AnsiCompareStr(Line1,Line2)=0);
+    end;
+  end;
+end;
+
+procedure CreateTextDiff(Text1, Text2, DiffText: TStrings;
+  Flags: TTextDiffFlags);
+var Cnt1, Cnt2, Line1, Line2: integer;
+begin
+  DiffText.Clear;
+  Cnt1:=Text1.Count;
+  Cnt2:=Text2.Count;
+  Line1:=1;
+  Line2:=1;
+  // read empty lines
+  if (tdfIgnoreEmptyLineChanges in Flags) then begin
+    while (Line1<Cnt1) and (IsEmptyLine(Text1[Line1],Flags)) do
+      inc(Line1);
+    while (Line2<Cnt2) and (IsEmptyLine(Text2[Line2],Flags)) do
+      inc(Line2);
+  end;
+  // read lines that are equal
+  while (Line1<Cnt1) and (Line2<Cnt2)
+  and LinesAreEqual(Text1[Line1],Text2[Line2],Flags) do begin
+    inc(Line1);
+    inc(Line2);
+  end;
+end;
+
+procedure InternalInit;
+var c: char;
+begin
+  for c:=Low(char) to High(char) do begin
+    IsSpaceChars[c]:=c in [' ',#9,#10,#13];
+    UpperCaseChars[c]:=upcase(c);
+  end;
+end;
+
+initialization
+  InternalInit;
+
+finalization
+
+
+end.
+