{ $Header: /MidiComp/MidiType.pas 2     10/06/97 7:33 Davec $ }

{ Written by David Churcher <dchurcher@cix.compulink.co.uk>,
  released to the public domain. }


unit MidiType;

interface

{$IFDEF FPC}
  {$MODE Delphi}
  {$H+} // use long strings
{$ENDIF}

uses
  Classes,
  Windows,
  Messages,
  MMSystem,
  MidiDefs,
  CircBuf;

type
	{-------------------------------------------------------------------}
	{ A MIDI input/output event }
	TMyMidiEvent = class(TPersistent)
	public
		MidiMessage: Byte;          { MIDI message status byte }
		Data1: Byte;            { MIDI message data 1 byte }
		Data2: Byte;            { MIDI message data 2 byte }
		Time: DWORD;          { Time in ms since midiInOpen }
		SysexLength: Word;  { Length of sysex data (0 if none) }
		Sysex: PChar;           { Pointer to sysex data buffer }
		destructor Destroy; override;   { Frees sysex data buffer if nec. }
	end;
	PMyMidiEvent = ^TMyMidiEvent;

	{-------------------------------------------------------------------}
	{ Encapsulates the MIDIHDR with its memory handle and sysex buffer }
	PMyMidiHdr = ^TMyMidiHdr;
	TMyMidiHdr = class(TObject)
	public
		hdrHandle: THandle;
		hdrPointer: PMIDIHDR;
		sysexHandle: THandle;
		sysexPointer: Pointer;
		constructor Create(BufferSize: Word);
		destructor Destroy; override;
	end;

implementation

{-------------------------------------------------------------------}
{ Free any sysex buffer associated with the event }
destructor TMyMidiEvent.Destroy;
begin
	if (Sysex <> Nil) then
		Freemem(Sysex, SysexLength);

	inherited Destroy;
end;

{-------------------------------------------------------------------}
{ Allocate memory for the sysex header and buffer }
constructor TMyMidiHdr.Create(BufferSize:Word);
begin
	inherited Create;

	if BufferSize > 0 then
		begin
		hdrPointer := GlobalSharedLockedAlloc(sizeof(TMIDIHDR), hdrHandle);
		sysexPointer := GlobalSharedLockedAlloc(BufferSize, sysexHandle);

		hdrPointer^.lpData := sysexPointer;
		hdrPointer^.dwBufferLength := BufferSize;
		end;
end;

{-------------------------------------------------------------------}
destructor TMyMidiHdr.Destroy;
begin
	GlobalSharedLockedFree( hdrHandle, hdrPointer );
	GlobalSharedLockedFree( sysexHandle, sysexPointer );
	inherited Destroy;
end;



end.