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Diffstat (limited to 'Game/Code/lib/midi/CIRCBUF.PAS')
| -rw-r--r-- | Game/Code/lib/midi/CIRCBUF.PAS | 183 |
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. |