Olive.Random/Renegade.Random.BSDRandom.pas

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{ ???: Todo - use arc4random_buf }
{$mode objfpc}{$H+}
Unit Renegade.Random.BSDRandom;

interface

uses
  CTypes,
  Objects,
  Classes,
  SysUtils,
  Renegade.Random.RandomInterface,
  Renegade.Random.URandom;

type
  PCChar = ^CChar;
  PBSDRandom = ^BSDRandom;
  BSDRandom = class (RandomTrait, RandomInterface)
    private
      function GetSystemBytes(var RandomByteBuffer : TBytes; NBytes : SizeUint) : CInt;
    public
      function GetBytes(NBytes : SizeUInt) : TBytes;
      function GetString(NBytes : SizeUInt) : AnsiString;
  end;

procedure arc4random_buf(var Buffer; NBytes : csize_t);
  cdecl;external 'c' name 'arc4random_buf';

implementation

function BSDRandom.GetSystemBytes(var RandomByteBuffer : TBytes; NBytes : SizeUint) : CInt;
var
  CharBuffer : array of pcuint8;
begin
  SetLength(CharBuffer, NBytes);
  arc4random_buf(CharBuffer[0], NBytes);
  if Length(CharBuffer) <> NBytes then
    begin
      RandomByteBuffer[0] := 0;
      Result := -1;
    end else
    begin
      Move(CharBuffer[Low(CharBuffer)], RandomByteBuffer[0], NBytes);
      Result := High(RandomByteBuffer);
    end;
end;

function BSDRandom.GetBytes(NBytes : SizeUInt) : TBytes;
var
  RandomBuffer : AnsiString;
begin
  SetLength(RandomBuffer, NBytes);
  SetLength(Result, NBytes);
  RandomBuffer := GetString(NBytes);
  Move(RandomBuffer[1], Result[0], NBytes);
end;

function BSDRandom.GetString(NBytes : SizeUInt) : AnsiString;
var
  RandomBuffer : TBytes;
  B : SizeInt;
begin
  SetLength(RandomBuffer, (NBytes*2));
  SetLength(Result, NBytes);
  B := GetSystemBytes(RandomBuffer, (NBytes*2));
  Move(RandomBuffer[0], Result[1], NBytes);
end;

end.