Pointer 'Pos'

{
  @params:
    Haystack:  Pointer to the haystack.
    Needle:    Pointer to the needle.
    ElmntSize: Size of each element.
    HaystkLen: Number of elements in haystack
    NeedleLen: Number of elements in needle
}
function Find(Haystack:Pointer; Needle:Pointer; ElmntSize:SizeInt; HaystkLen, NeedleLen:UInt32): Int32;
var
  i,hi,lo,ss:Int32;
  PBData,PBSeek,P,Q:PChar;
begin
  PBData := PChar(Haystack);
  PBSeek := PChar(Needle);
  P := PBData[0];
  Q := PBSeek[0];
  SS := (ElmntSize*NeedleLen);
  lo := Int32(PBData[0]);
  hi := Int32(PBData[HaystkLen*ElmntSize] - SS);
  while hi > UInt32(P) do
  begin
    if (Q^ <> P^) then begin
      inc(p,ElmntSize);
      continue;
    end;
    if CompareMem(Q, P, SS) then
      Exit((UInt32(P)-lo) div ElmntSize);
    inc(p,ElmntSize);
  end;
  Exit(-1);
end;


var
  TIA: TIntegerArray;   ValI: Int32;
  TBA: TByteArray;      ValB: Byte;
  TPA: TPointArray;     ValTPA: TPointArray;     ValPT: TPoint;
begin
  // Int in integer array.
  TIA := [0,1,2,3,4,5,6,7,8,9];
  ValI := 5;
  WriteLn( Find( Pointer(TIA), @ValI, SizeOf(Int32), Length(TIA), 1 ) );

  // Point-Array in Point-Array
  TPA := [[0,0],[1,1],[2,2],[3,3],[4,4],[5,5],[6,6],[7,7],[8,8],[9,9]];
  ValTPA := [[5,5], [6,6]];
  WriteLn( Find( Pointer(TPA), Pointer(ValTPA), SizeOf(TPoint), Length(TPA), Length(ValTPA) ) );

  // Point in Point-Array
  ValPT := Point(5,5);
  WriteLn( Find( Pointer(TPA), @ValPT, SizeOf(TPoint), Length(TPA), 1 ) );

  //byte in Byte-Array.
  TBA := [0,1,2,3,4,5,6,7,8,9];
  ValB := 5;
  WriteLn( Find( Pointer(TBA), @ValB, SizeOf(Byte), Length(TBA), 1 ) );
end.