workbench/libs/camd/querysysex.c

   1 /*
   2     Copyright © 1995-2007, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     Desc:
   6     Lang: English
   7 */
   8
   9 #include <proto/exec.h>
  10
  11 #include "camd_intern.h"
  12
  13
  14 /*****************************************************************************
  15
  16     NAME */
  17
  18         AROS_LH1(ULONG, QuerySysEx,
  19
  20 /*  SYNOPSIS */
  21         AROS_LHA(struct MidiNode *, midinode, A0),
  22
  23 /*  LOCATION */
  24         struct CamdBase *, CamdBase, 28, Camd)
  25
  26 /*  FUNCTION
  27        Returns the number of bytes remaining in the current sys/ex message.
  28
  29     INPUTS
  30        midinode - pointer to MidiNode
  31
  32     RESULT
  33        Remaining bytes in sys/ex message.      0 is returned if the last
  34        message read from GetMidi() wasn't a sys/ex message.
  35
  36     NOTES
  37
  38     EXAMPLE
  39
  40     BUGS
  41                 Tested.
  42
  43     SEE ALSO
  44                 SkipSysEx(), GetSysEx()
  45
  46     INTERNALS
  47
  48     HISTORY
  49
  50         2001-01-12 ksvalast first created
  51         2005-06-30 Lyle Hazelwood fixed sum to include EOX byte
  52         2006-01-28 fixed wraparound bug (buffer overflow)
  53
  54 *****************************************************************************/
  55 {
  56     AROS_LIBFUNC_INIT
  57
  58         struct MyMidiNode *mymidinode=(struct MyMidiNode *)midinode;
  59         UBYTE *sysex;
  60         ULONG numleft=1;
  61
  62         if(mymidinode->lastreadstatus!=0xf0) return 0;
  63
  64         ObtainSemaphore(&mymidinode->sysexsemaphore2);
  65
  66                 if(mymidinode->sysex_nextis0==TRUE){
  67                         ReleaseSemaphore(&mymidinode->sysexsemaphore2);
  68                         return 0;
  69                 }
  70
  71                 sysex=mymidinode->sysex_read;
  72
  73                 while(*sysex!=0xf7){
  74                         numleft++;
  75                         sysex++;
  76                         if(sysex == mymidinode->sysex_end)
  77                           sysex = mymidinode->sysex_start;
  78                 }
  79
  80         ReleaseSemaphore(&mymidinode->sysexsemaphore2);
  81
  82         return numleft;
  83
  84    AROS_LIBFUNC_EXIT
  85 }
  86
  87
  88