Hi, it must be that I've been working for more than 8 hrs but I can't find where the problem is...

I need to pass a file via stdIn to TProcess, then capture the StdOut. This program should do what I expect, but, instead it hangs after writing aprox 293000 bytes to Proc.Input stream.

Can you take a look at it?.

program test;
{$mode objfpc}{$H+}

uses
SysUtils, Classes,
process,

  math;

function CompressLZMA(AStream: TMemoryStream): TMemoryStream;
var
  Proc: TProcess;
  lBuffer: array [0..2048] of byte;
  ReadCount: integer;
  lPos: LongInt;
begin
  Result := TMemoryStream.Create;
  AStream.Position:= 0;
  writeln('-1-');
  Proc := TProcess.Create(nil); //Create a new process
  try
    Proc.Executable := '/usr/bin/lzma'; //Run lzma
    Proc.Parameters.Add('--compress');
    Proc.Options := [poUsePipes, poStderrToOutPut];
    Proc.Execute;
    writeln(format('Writing %d bytes...', [AStream.Size]));
    lPos := 0;
    while(lPos < AStream.Size) do
    begin
      writeln(format('Pos: %d - Size: %d', [lPos, AStream.Size]));
      ReadCount := AStream.Read(lBuffer, SizeOf(lBuffer));
      Proc.Input.Write(lBuffer, ReadCount);
      lPos := lPos + ReadCount;
    end;
  writeln('-2-');
    Proc.CloseInput;
  writeln('-3-');
    while Proc.Running or (Proc.Output.NumBytesAvailable > 0) do
    begin
  writeln('-4-');
      while Proc.Output.NumBytesAvailable > 0 do
      begin
        ReadCount := Min(512, Proc.Output.NumBytesAvailable);
        Proc.Output.Read(lBuffer, ReadCount);
        Result.Write(lBuffer, ReadCount);
        writeln(format('%d', [ReadCount]));
      end;
    end;
    Result.Position:= 0;
  finally
    Proc.Free;
  end;
end;
var
  lStr: TMemoryStream;
begin
  lStr := TMemoryStream.Create;
  try
    lStr.LoadFromFile('binary.file');
    CompressLZMA(lStr).SaveToFile('output.lzma');
  finally
    lStr.Free;
  end;
end.

After every write to Input, read all available from Output and StdErr.

Mattias

Thanks Mattias, I went a step further.

Sadly now I'm getting an "unexpected end of input" error when I try to decompress the generated file using "lzma -d -c output.lzma > output.dcm".

Attached is the modified program.

Regards,

Check return value of Proc.Input.Write.
And call Proc.CloseInput when your input was written completely.

Mattias

Mmm, I'm getting the same result.

I attached the new code.

When you give Proc.Input.Write 200 bytes and it returns that the other process could only process 100 of them. What bytes do you have to write next?

Mattias

Sorry, I'm not getting it. Which other process?, apart from that, Proc.Input.Write is always returning the sizeof(buffer) except when it reaches the end, where it can be less than it.

It seems that the Proc.Input part is ok, aparently the Proc.Output is wrong :(

I attached a slightly modified code.

Finally got it working, I was forgetting to read the last part of the Output stream. ...I still don't know why this last chunk of bytes doesn't show up in NumBytesAvailable.

I attached the code.

Regards,

NumBytesAvailable is inherently unreliable. I didn't like it's addition.

You should never use it in critical code.

Michael.

Maybe that's why the same program doesn't work on FreeBSD?. What can I use instead of it?.

Read until the number of read bytes is zero.

Michael.

This cannot be done, because when you don't have bytes available, Proc.Output.Read hangs.

Not if the process stops and closes it's output, then it should return with the last bytes in the buffer.

Michael.