Fixed Size Buffers

From RemObjects Software

This is a Oxygene Language Feature topic
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In unsafe code blocks, it's possible to declare fixed-size structures containing embedded arrays.

The arrays are placed inline and they can only be defined inside a class or record as a field or as a local variable:

type
  myrec = record
    chars: inline array[0..255] of char;
    ints: inline array[1..5,1..9] of integer;
  end;

Note: if the code above does not compile ('Unsafe code not allowed'), you will need to adjust the project option allowing unsafe code.

Rules

The following rules apply to inline arrays:

• they cannot be used as regular types
• they must be declared within an unsafe method
• they can have multiple dimensions but the dimensions all have to be defined (unlike regular arrays)
• the subtype must be one of : smallint, shortint, integer(longint), int64, byte, word, cardinal(longword), uint64, double, single, boolean, char

Example

type
  Counts = record
    Squares: inline array[1..20] of integer;
    Cubes: inline array[1..20] of integer;
  end;

  MainForm = class(System.Windows.Forms.Form)
  public
    constructor Create;
    class method Main;
    method Test; unsafe;
  end;

implementation

method MainForm.Test;
var
  c: Counts;
  i: Integer;
begin
  for i := 1 to 20 do begin
    c.Squares[i] := i*i;
    c.Cubes[i] := i*c.Squares[i];
  end;
end;

See Also

• Array Types
• Types

Product: RemObjects Oxygene (formerly known as Chrome)
Current version: 3.0 Previous Versions: 'Joyride' (2.0), 'Floorshow' (1.5), 'Adrenochrome' (1.0)

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