Re: This MIDI stuff, would someone be interested in reviewing my code?

[Christophe Chaumet <devteam@chaumetsoftware.com>]

John McCabe a �crit :
> Hi
>
> It's still early days but, if I'm going to be using Ada to try to
> build this app I want, it would be nice to write it in a style that
> looks appropriate. I'm aware of the Q&S guide but I was hoping that
> someone could take a quick look at the code I've written (it's only 80
> lines or so, and it's down below) and see if there's anything
> obviously stupid I'm doing.
>
> My specific thoughts on this are:
>
> 1) Perhaps I should be using limited withs in some places to get
> access to the primitive operators/functions of the stuff in
> Interfaces.C/.strings and Win32 etc.
>
> 2) The for loops: for devId in Win32.UINT range 0..(NumOutputDevices -
> 1) etc. These are protected by a "if NumOutputDevices < 0" condition
> but before I realised my mistake I found that when NumOutputDevices is
> 0, the loop executes as many times as it can before it crashed. This
> was obviously because NumOutputDevices was 0, so the range
> "0..(NumOutputDevices - 1)" was 0..4929blahblah due to Win32.UINT
> being a modular type. I looked at the option to use something like:
>    for index in Win32.UINT range 1..NumOuputDevices loop
>       declare
>          devId : Win32.UINT := index - 1;
>       begin
>          ...
>       end;
>    end loop;
> but stuck with the original with the conditional round it.
>
> 3) Would it be more appropriate to use something like
> Win32.UINT'Image() instead of getting an instantiation of the
> Modular_IO package?
>
> Anyway - thanks to anyone who can be bothered to look at this. It will
> be much appreciated, and thanks for everyone's help so far.
>
> John
>
>
> ===================
> with Ada.Text_IO;
> with Ada.Unchecked_Deallocation;
>
> with Interfaces.C; use Interfaces.C;
> with Interfaces.C.Strings; use Interfaces.C.Strings;
>
> with Win32; use Win32;
> with Win32.Mmsystem; use Win32.Mmsystem;
>
> procedure MidiDevs is
>     NumInputDevices  : Win32.UINT;
>     NumOutputDevices : Win32.UINT;
>
>     res         : Win32.Mmsystem.MMRESULT;
>     midiInCaps  : Win32.Mmsystem.LPMIDIINCAPS;
>     midiOutCaps : Win32.Mmsystem.LPMIDIOUTCAPS;
>
>     package UINTText_IO is new Ada.Text_IO.Modular_IO(Win32.UINT);
>     package MMText_IO is new
> Ada.Text_IO.Modular_IO(Win32.Mmsystem.MMRESULT);
>
>     procedure Free is new
> Ada.Unchecked_Deallocation(Win32.Mmsystem.MIDIINCAPS,
> Win32.Mmsystem.LPMIDIINCAPS);
>     procedure Free is new
> Ada.Unchecked_Deallocation(Win32.Mmsystem.MIDIOUTCAPS,
> Win32.Mmsystem.LPMIDIOUTCAPS);
>
> begin
>    NumInputDevices := Win32.Mmsystem.midiInGetNumDevs;
>    NumOutputDevices := Win32.Mmsystem.midiOutGetNumDevs;
>    midiInCaps  := new Win32.Mmsystem.MIDIINCAPS;
>    midiOutCaps := new Win32.Mmsystem.MIDIOUTCAPS;
>
>    Ada.Text_IO.Put("There are ");
>    UINTText_IO.Put(NumInputDevices, 0);
>    Ada.Text_IO.Put(" input devices available, and ");
>    UINTText_IO.Put(NumOutputDevices, 0);
>    Ada.Text_IO.Put_Line(" output devices available.");
>
>    if NumInputDevices > 0
>    then
>       Ada.Text_IO.New_Line;
>       Ada.Text_IO.Put("The ");
>       UINTText_IO.Put(NumInputDevices, 0);
>       Ada.Text_IO.Put_Line(" input devices are:");
>       Ada.Text_IO.New_Line;
>
>       for devId in Win32.UINT range 0..(NumInputDevices - 1)
>       loop
>          res := Win32.Mmsystem.midiInGetDevCaps(devId,
>                                                 midiInCaps,
>
> (Win32.Mmsystem.MIDIINCAPS'size * Win32.BYTE'size));
>          UINTText_IO.Put(devId, 0);
>          Ada.Text_IO.Put(") ");
>          if res = Win32.Mmsystem.MMSYSERR_NOERROR
>          then
>             Ada.Text_IO.Put("szPname = ");
>             Ada.Text_IO.Put_Line(To_Ada(To_C(midiInCaps.szPname)));
>          else
>             Ada.Text_IO.Put("Query Failed. Returned ");
>             MMText_IO.Put(res, 0);
>          end if;
>          Ada.Text_IO.New_Line;
>       end loop;
>    end if;
>
>    if NumOutputDevices > 0
>    then
>       Ada.Text_IO.New_Line;
>       Ada.Text_IO.Put("The ");
>       UINTText_IO.Put(NumOutputDevices, 0);
>       Ada.Text_IO.Put_Line(" output devices are:");
>       Ada.Text_IO.New_Line;
>
>       for devId in Win32.UINT range 0..(NumOutputDevices - 1)
>       loop
>          res := Win32.Mmsystem.midiOutGetDevCaps(devId,
>                                                  midiOutCaps,
>
> (Win32.Mmsystem.MIDIOUTCAPS'size * Win32.BYTE'size));
>          UINTText_IO.Put(devId, 0);
>          Ada.Text_IO.Put(") ");
>          if res = Win32.Mmsystem.MMSYSERR_NOERROR
>          then
>             Ada.Text_IO.Put("szPname = ");
>             Ada.Text_IO.Put_Line(To_Ada(To_C(midiOutCaps.szPname)));
>          else
>             Ada.Text_IO.Put("Query Failed. Returned ");
>             MMText_IO.Put(res, 0);
>          end if;
>          Ada.Text_IO.New_Line;
>       end loop;
>    end if;
>
>    Free(midiInCaps);
>    Free(midiOutCaps);
>    
> end MidiDevs;
>
>   
Here is a working code: http://sourceforge.net/projects/canta/ written 
in Ada.