Changeset 52 for branches/ByteArray/BigInt.pas

Timestamp:

Nov 16, 2023, 2:01:59 PM (6 months ago)

Author:

chronos

Message:

• Modified: BigInt implementation improvements.

File:

• branches/ByteArray/BigInt.pas (modified) (8 diffs)

branches/ByteArray/BigInt.pas

@@ -47 +47 @@
     class operator GreaterThanOrEqual(A, B: TBigInt): Boolean;
     procedure Shrink;
+    function IsNegative: Boolean;
+    function IsZero: Boolean;
+    function IsPositive: Boolean;
     procedure SetByteArray(AData: TArrayOfByte; ASize: TBigIntSize);
     procedure GetByteArray(var AData: TArrayOfByte; ASize: TBigIntSize);
     function Copy(Size: TBigIntSize): TBigInt;
-    property Size: Byte read GetSize write SetSize;
+    property Size: TBigIntSize read GetSize write SetSize;
     property Data[Index: TBigIntSize]: Byte read GetData write SetData;
   end;
@@ -85 +88 @@
 procedure TBigInt.SetData(Index: TBigIntSize; AValue: Byte);
 begin
-  if Index > Size - 1 then Size := Index + 1;
+  if Index > Integer(Size) - 1 then Size := Index + 1;
   FData[Index] := AValue;
 end;
@@ -241 +244 @@
   Carry: Byte;
 begin
-  Result.Size := A.Size;
+  Result.Size := Max(A.Size, B.Size);
   Carry := 0;
   I := 0;
@@ -259 +262 @@
 begin
   Result := A.Size = B.Size;
+  if not Result then Exit;
   for I := 0 to A.Size - 1 do
     if A.FData[I] <> B.FData[I] then begin
@@ -271 +275 @@
 begin
   Result := A.Size = B.Size;
+  if not Result then Exit;
   for I := 0 to A.Size - 1 do
     if A.FData[I] <> B.FData[I] then begin
@@ -280 +285 @@
 
 class operator TBigInt.LessThan(A, B: TBigInt): Boolean;
-begin
-
+var
+  Temp: TBigInt;
+begin
+  Temp := A - B;
+  Result := Temp.IsNegative;
 end;
 
 class operator TBigInt.LessThanOrEqual(A, B: TBigInt): Boolean;
-begin
-
+var
+  Temp: TBigInt;
+begin
+  Temp := A - B;
+  Result := Temp.IsNegative or Temp.IsZero;
 end;
 
 class operator TBigInt.GreaterThan(A, B: TBigInt): Boolean;
-begin
-
+var
+  Temp: TBigInt;
+begin
+  Temp := A - B;
+  Result := Temp.IsPositive and not Temp.IsZero;
 end;
 
 class operator TBigInt.GreaterThanOrEqual(A, B: TBigInt): Boolean;
-begin
-
+var
+  Temp: TBigInt;
+begin
+  Temp := A - B;
+  Result := Temp.IsPositive;
 end;
 
@@ -307 +324 @@
     Dec(I);
   Size := I + 1;
+end;
+
+function TBigInt.IsNegative: Boolean;
+begin
+  Result := (FData[Size - 1] and $80) = $80;
+end;
+
+function TBigInt.IsZero: Boolean;
+var
+  I: TBigIntSize;
+begin
+  Result := True;
+  for I := 0 to Size - 1 do
+    if FData[I] <> 0 then begin
+      Result := False;
+      Break;
+    end;
+end;
+
+function TBigInt.IsPositive: Boolean;
+begin
+  Result := (FData[Size - 1] and $80) = 0;
 end;
 
@@ -329 +368 @@
     4: PDWord(@Result.FData[0])^ := PDWord(@FData[0])^;
     8: PQWord(@Result.FData[0])^ := PQWord(@FData[0])^;
+    else Move(PByte(@FData[0])^, PByte(@Result.FData[0])^, Size);
   end;
 end;