aboutsummaryrefslogtreecommitdiffstats
path: root/Game/Code/lib/midi/CIRCBUF.PAS
diff options
context:
space:
mode:
Diffstat (limited to 'Game/Code/lib/midi/CIRCBUF.PAS')
-rw-r--r--Game/Code/lib/midi/CIRCBUF.PAS183
1 files changed, 0 insertions, 183 deletions
diff --git a/Game/Code/lib/midi/CIRCBUF.PAS b/Game/Code/lib/midi/CIRCBUF.PAS
deleted file mode 100644
index 77cb3643..00000000
--- a/Game/Code/lib/midi/CIRCBUF.PAS
+++ /dev/null
@@ -1,183 +0,0 @@
-{ $Header: /MidiComp/CIRCBUF.PAS 2 10/06/97 7:33 Davec $ }
-
-{ Written by David Churcher <dchurcher@cix.compulink.co.uk>,
- released to the public domain. }
-
-
-{ A First-In First-Out circular buffer.
- Port of circbuf.c from Microsoft's Windows MIDI monitor example.
- I did do a version of this as an object (see Rev 1.1) but it was getting too
- complicated and I couldn't see any real benefits to it so I dumped it
- for an ordinary memory buffer with pointers.
-
- This unit is a bit C-like, everything is done with pointers and extensive
- use is made of the undocumented feature of the Inc() function that
- increments pointers by the size of the object pointed to.
- All of this could probably be done using Pascal array notation with
- range-checking turned off, but I'm not sure it's worth it.
-}
-
-Unit Circbuf;
-
-interface
-
-{$IFDEF FPC}
- {$MODE Delphi}
- {$H+} // use AnsiString
-{$ENDIF}
-
-Uses
- Windows,
- MMSystem;
-
-type
- { MIDI input event }
- TMidiBufferItem = record
- timestamp: DWORD; { Timestamp in milliseconds after midiInStart }
- data: DWORD; { MIDI message received }
- sysex: PMidiHdr; { Pointer to sysex MIDIHDR, nil if not sysex }
- end;
- PMidiBufferItem = ^TMidiBufferItem;
-
- { MIDI input buffer }
- TCircularBuffer = record
- RecordHandle: HGLOBAL; { Windows memory handle for this record }
- BufferHandle: HGLOBAL; { Windows memory handle for the buffer }
- pStart: PMidiBufferItem; { ptr to start of buffer }
- pEnd: PMidiBufferItem; { ptr to end of buffer }
- pNextPut: PMidiBufferItem; { next location to fill }
- pNextGet: PMidiBufferItem; { next location to empty }
- Error: Word; { error code from MMSYSTEM functions }
- Capacity: Word; { buffer size (in TMidiBufferItems) }
- EventCount: Word; { Number of events in buffer }
- end;
-
- PCircularBuffer = ^TCircularBuffer;
-
-function GlobalSharedLockedAlloc( Capacity: Word; var hMem: HGLOBAL ): Pointer;
-procedure GlobalSharedLockedFree( hMem: HGLOBAL; ptr: Pointer );
-
-function CircbufAlloc( Capacity: Word ): PCircularBuffer;
-procedure CircbufFree( PBuffer: PCircularBuffer );
-function CircbufRemoveEvent( PBuffer: PCircularBuffer ): Boolean;
-function CircbufReadEvent( PBuffer: PCircularBuffer; PEvent: PMidiBufferItem ): Boolean;
-{ Note: The PutEvent function is in the DLL }
-
-implementation
-
-{ Allocates in global shared memory, returns pointer and handle }
-function GlobalSharedLockedAlloc( Capacity: Word; var hMem: HGLOBAL ): Pointer;
-var
- ptr: Pointer;
-begin
- { Allocate the buffer memory }
- hMem := GlobalAlloc(GMEM_SHARE Or GMEM_MOVEABLE Or GMEM_ZEROINIT, Capacity );
-
- if (hMem = 0) then
- ptr := Nil
- else
- begin
- ptr := GlobalLock(hMem);
- if (ptr = Nil) then
- GlobalFree(hMem);
- end;
-
- GlobalSharedLockedAlloc := Ptr;
-end;
-
-procedure GlobalSharedLockedFree( hMem: HGLOBAL; ptr: Pointer );
-begin
- if (hMem <> 0) then
- begin
- GlobalUnlock(hMem);
- GlobalFree(hMem);
- end;
-end;
-
-function CircbufAlloc( Capacity: Word ): PCircularBuffer;
-var
- NewCircularBuffer: PCircularBuffer;
- NewMIDIBuffer: PMidiBufferItem;
- hMem: HGLOBAL;
-begin
- { TODO: Validate circbuf size, <64K }
- NewCircularBuffer :=
- GlobalSharedLockedAlloc( Sizeof(TCircularBuffer), hMem );
- if (NewCircularBuffer <> Nil) then
- begin
- NewCircularBuffer^.RecordHandle := hMem;
- NewMIDIBuffer :=
- GlobalSharedLockedAlloc( Capacity * Sizeof(TMidiBufferItem), hMem );
- if (NewMIDIBuffer = Nil) then
- begin
- { TODO: Exception here? }
- GlobalSharedLockedFree( NewCircularBuffer^.RecordHandle,
- NewCircularBuffer );
- NewCircularBuffer := Nil;
- end
- else
- begin
- NewCircularBuffer^.pStart := NewMidiBuffer;
- { Point to item at end of buffer }
- NewCircularBuffer^.pEnd := NewMidiBuffer;
- Inc(NewCircularBuffer^.pEnd, Capacity);
- { Start off the get and put pointers in the same position. These
- will get out of sync as the interrupts start rolling in }
- NewCircularBuffer^.pNextPut := NewMidiBuffer;
- NewCircularBuffer^.pNextGet := NewMidiBuffer;
- NewCircularBuffer^.Error := 0;
- NewCircularBuffer^.Capacity := Capacity;
- NewCircularBuffer^.EventCount := 0;
- end;
- end;
- CircbufAlloc := NewCircularBuffer;
-end;
-
-procedure CircbufFree( pBuffer: PCircularBuffer );
-begin
- if (pBuffer <> Nil) then
- begin
- GlobalSharedLockedFree(pBuffer^.BufferHandle, pBuffer^.pStart);
- GlobalSharedLockedFree(pBuffer^.RecordHandle, pBuffer);
- end;
-end;
-
-{ Reads first event in queue without removing it.
- Returns true if successful, False if no events in queue }
-function CircbufReadEvent( PBuffer: PCircularBuffer; PEvent: PMidiBufferItem ): Boolean;
-var
- PCurrentEvent: PMidiBufferItem;
-begin
- if (PBuffer^.EventCount <= 0) then
- CircbufReadEvent := False
- else
- begin
- PCurrentEvent := PBuffer^.PNextget;
-
- { Copy the object from the "tail" of the buffer to the caller's object }
- PEvent^.Timestamp := PCurrentEvent^.Timestamp;
- PEvent^.Data := PCurrentEvent^.Data;
- PEvent^.Sysex := PCurrentEvent^.Sysex;
- CircbufReadEvent := True;
- end;
-end;
-
-{ Remove current event from the queue }
-function CircbufRemoveEvent(PBuffer: PCircularBuffer): Boolean;
-begin
- if (PBuffer^.EventCount > 0) then
- begin
- Dec( Pbuffer^.EventCount);
-
- { Advance the buffer pointer, with wrap }
- Inc( Pbuffer^.PNextGet );
- If (PBuffer^.PNextGet = PBuffer^.PEnd) then
- PBuffer^.PNextGet := PBuffer^.PStart;
-
- CircbufRemoveEvent := True;
- end
- else
- CircbufRemoveEvent := False;
-end;
-
-end.