Delphi XE3 -> Integer to array of Bytes

Question

I have a data structure:

data = array of integer;

I have filled it from an

source = array of byte;

with

Answer 1

Hmmm... I see an answer using Move and one using shifts, but what about a simple cast?:

var
  I: Integer;
  B: array[0..3] of Byte;
begin
  // from bytes to integer:
  I := PInteger(@B)^;
  // from integer to bytes:
  PInteger(@B)^ := I;

Or with your arrays:

data[i] := PInteger(@source[offset])^;

and vice versa:

// get low byte
source[offset] := PByte(@data[i])^; // or := PByte(@data[i])[0];
// get second byte
secondByte := PByte(@data[i])[1]; // or := (PByte(@data[i]) + 1)^;

or

PInteger(@source[offset])^ := data[i];

As you see, you can get a long way by casting to pointers. This does not actually take the pointer, the compiler is clever enough to access the items directly.