changed license to GPLv3 only; sorry, no trust to FSF anymore

[d2df-sdl.git] / src / shared / binheap.pas

diff --git a/src/shared/binheap.pas b/src/shared/binheap.pas
index 968c5f94221e63a73ced2a96a109eda6ff99daf0..e3ff3e742870f89fda244fd1b86152e35a1cfe67 100644 (file)
--- a/src/shared/binheap.pas
+++ b/src/shared/binheap.pas
@@ -1,9 +1,8 @@
-(* Copyright (C)  DooM 2D:Forever Developers
+(* Copyright (C)  Doom 2D: Forever Developers
  *
  * This program 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 3 of the License, or
- * (at your option) any later version.
+ * the Free Software Foundation, version 3 of the License ONLY.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ -20,33 +19,52 @@ unit binheap;
 interface
 
 
+(*
+ * CmpObjT: class that contains class methods:
+ *   class function less (const[ref] a, b: KeyT): Boolean;
+ *)
 type
-  TBinaryHeapLessFn = function (a, b: TObject): Boolean;
-
-  TBinaryHeapObj = class(TObject)
+  // WARNING! don't put structures into heap, use ponters or ids!
+  generic TBinaryHeapBase<ITP, CmpObjT> = class(TObject)
   private
-    elem: array of TObject;
+    elem: array of ITP;
     elemUsed: Integer;
-    lessfn: TBinaryHeapLessFn;
 
   private
     procedure heapify (root: Integer);
 
   public
-    constructor Create (alessfn: TBinaryHeapLessFn);
+    constructor Create ();
     destructor Destroy (); override;
 
     procedure clear ();
 
-    procedure insert (val: TObject);
+    procedure insert (val: ITP);
 
-    function front (): TObject;
+    function front (): ITP;
     procedure popFront ();
 
     property count: Integer read elemUsed;
   end;
 
 
+type
+  TBinHeapKeyIntLess = class
+  public
+    class function less (const a, b: Integer): Boolean; inline;
+  end;
+
+  TBinHeapKeyIntGreat = class
+  public
+    class function less (const a, b: Integer): Boolean; inline;
+  end;
+
+
+type
+  TBinaryHeapIntLess = specialize TBinaryHeapBase<Integer, TBinHeapKeyIntLess>;
+  TBinaryHeapIntGreat = specialize TBinaryHeapBase<Integer, TBinHeapKeyIntGreat>;
+
+
 implementation
 
 uses
@@ -54,40 +72,43 @@ uses
 
 
 // ////////////////////////////////////////////////////////////////////////// //
-constructor TBinaryHeapObj.Create (alessfn: TBinaryHeapLessFn);
+class function TBinHeapKeyIntLess.less (const a, b: Integer): Boolean; inline; begin result := (a < b); end;
+class function TBinHeapKeyIntGreat.less (const a, b: Integer): Boolean; inline; begin result := (a > b); end;
+
+
+// ////////////////////////////////////////////////////////////////////////// //
+constructor TBinaryHeapBase.Create ();
 begin
-  if not assigned(alessfn) then raise Exception.Create('wutafuck?!');
-  lessfn := alessfn;
-  SetLength(elem, 8192); // 'cause why not?
+  SetLength(elem, 128); // 'cause why not?
   elemUsed := 0;
 end;
 
 
-destructor TBinaryHeapObj.Destroy ();
+destructor TBinaryHeapBase.Destroy ();
 begin
   elem := nil;
   inherited;
 end;
 
 
-procedure TBinaryHeapObj.clear ();
+procedure TBinaryHeapBase.clear ();
 begin
   elemUsed := 0;
 end;
 
 
-procedure TBinaryHeapObj.heapify (root: Integer);
+procedure TBinaryHeapBase.heapify (root: Integer);
 var
   smallest, right: Integer;
-  tmp: TObject;
+  tmp: ITP;
 begin
   while true do
   begin
     smallest := 2*root+1; // left child
     if (smallest >= elemUsed) then break; // anyway
     right := smallest+1; // right child
-    if not lessfn(elem[smallest], elem[root]) then smallest := root;
-    if (right < elemUsed) and (lessfn(elem[right], elem[smallest])) then smallest := right;
+    if not CmpObjT.less(elem[smallest], elem[root]) then smallest := root;
+    if (right < elemUsed) and (CmpObjT.less(elem[right], elem[smallest])) then smallest := right;
     if (smallest = root) then break;
     // swap
     tmp := elem[root];
@@ -98,31 +119,38 @@ begin
 end;
 
 
-procedure TBinaryHeapObj.insert (val: TObject);
+procedure TBinaryHeapBase.insert (val: ITP);
 var
   i, par: Integer;
 begin
-  if (val = nil) then exit;
+  //if (val = nil) then exit;
   i := elemUsed;
-  if (i = Length(elem)) then SetLength(elem, Length(elem)+16384); // arbitrary number
+  // grow?
+  if (i = Length(elem)) then
+  begin
+    if (i <= 65536) then par := i*2 else par := i+65536; // arbitrary numbers
+    SetLength(elem, par);
+  end;
+  // increase counter
   Inc(elemUsed);
+  // insert element
   while (i <> 0) do
   begin
     par := (i-1) div 2; // parent
-    if not lessfn(val, elem[par]) then break;
+    if not CmpObjT.less(val, elem[par]) then break;
     elem[i] := elem[par];
     i := par;
   end;
   elem[i] := val;
 end;
 
-function TBinaryHeapObj.front (): TObject;
+function TBinaryHeapBase.front (): ITP;
 begin
-  if elemUsed > 0 then result := elem[0] else result := nil;
+  if elemUsed > 0 then result := elem[0] else result := Default(ITP);
 end;
 
 
-procedure TBinaryHeapObj.popFront ();
+procedure TBinaryHeapBase.popFront ();
 begin
   if (elemUsed > 0) then
   begin