Source30


unit PrimeRangeThread;

interface

uses
Classes, BlockToAsyncBuf;

type
TPrimeRangeThread = class(TThread)
private
{ Private declarations }
FBuf: TBlockToAsyncBuf;
protected
function IsPrime(TestNum: integer): boolean;
procedure Execute; override;
public
published
property Buf: TBlockToAsyncBuf read FBuf write FBuf;
end;

TRangeRequestType = record
Low, High: integer;
end;

PRangeRequestType = ^TRangeRequestType;

{ Results returned in a string list }

implementation

uses SysUtils;

{ TPrimeRangeThread }

function TPrimeRangeThread.IsPrime(TestNum: integer): boolean;

var
iter: integer;

begin
result := true;
if TestNum < 0 then
result := false;
if TestNum <= 2 then
exit;
iter := 2;
while (iter < TestNum) and (not terminated) do {Line A}
begin
if (TestNum mod iter) = 0 then
begin
result := false;
exit;
end;
Inc(iter);
end;
end;

procedure TPrimeRangeThread.Execute;

var
PRange: PRangeRequestType;
TestNum: integer;
Results: TStringList;

begin
while not Terminated do
begin
PRange := PRangeRequestType(FBuf.BlockingRead);
if Assigned(PRange) then
begin
Assert(PRange.Low <= PRange.High);
Results := TStringList.Create;
Results.Add('Primes from: ' + IntToStr(PRange.Low) +
' to: ' + IntToStr(PRange.High));
for TestNum := PRange.Low to PRange.High do
begin
if IsPrime(TestNum) then
Results.Add(IntToStr(TestNum) + ' is prime.');
end;
if not FBuf.BlockingWrite(Results) then
begin
Results.Free;
Terminate;
end;
end
else Terminate;
end;
end;

end.