First we need to declare 2 types
type
(* declare a dynamic array of Byte type *)
TypeByteArray = array of Byte;
(* declare a dynamic array of PByte type *)
TypePtrByteArray = array of PByte;
and now we need the utility functions which translates a pointer to an array of bytes, these utility functions take 2 parameters, the first parameter is the pointer to a variable(the @ operator can be used) and the second parameter takes the size in bytes of the variable, for instance if we pass a Integer value then the parameters should look like so: (@myInteger, 4), if the size of the passed parameter is 4 then you do not need to pass the second parameter, because it is declared as a constant of 4 bytesfunction PointerToByteArray(
(* the pointer to variable,
@ operator can be used *)
Value: Pointer;
(* the size in bytes of the
variable:
Byte = 1
Word = 2
Integer/Cardinal = 4
Double = 7
Int64 = 8 *)
const SizeInBytes: Cardinal = 4
): TypeByteArray;
var Address, (* store the address locally *)
index: integer; (* for loop *)
begin
(* get the pointer address *)
Address := Integer(Value);
(* set the length of the array *)
SetLength(Result, SizeInBytes);
(* loop to get all bytes *)
for index := 0 to SizeInBytes do
(* convert the address + index to a PByte pointer,
use the ^ operator so compiler knows that
we refer to the pointer's value *)
Result[index] := PByte(Ptr(Address + Index))^;
end;
function PointerToPtrByteArray
(* the pointer to variable,
@ operator can be used *)
(Value: Pointer;
(* the size in bytes of the
variable:
Byte = 1
Word = 2
Integer/Cardinal = 4
Double = 7
Int64 = 8 *)
const SizeinBytes: Cardinal = 4): TypePtrByteArray;
var Address, (* store the address locally *)
index: integer; (* for loop *)
begin
(* get the pointer address *)
Address := Integer(Value);
(* set the length of the array *)
SetLength(Result, SizeInBytes);
(* loop to get all bytes *)
for index := 0 to SizeInBytes do
(* convert the address + index to a PByte pointer *)
Result[index] := Ptr(Address + Index);
end;
An example of getting an integer value as an array of bytes and display each byte valueprocedure TForm1.Button1Click(Sender: TObject);
const
CH_CR = #13; (* da' return char *)
var
value: Integer;
s: String;
arr: TypeByteArray;
index: integer;
begin
(* assign a value to "Value" variable *)
value := 2009;
(* store the bytes on our dynamic array *)
arr := PointerToByteArray(@Value);
(* loop to get each byte from array *)
for index := 0 to 3 do
s := s + CH_CR + IntToStr(arr[index]);
(* display array values in a message *)
ShowMessage(s);
(* resize the array to 0 elements *)
SetLength(arr, 0);
(* nil it *)
arr := nil;
end;
