/**************************************************************************
 *
 *  THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY
 *  KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
 *  IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR
 *  PURPOSE.
 *
 *  Copyright (c) 1993 - 1995  Microsoft Corporation.  All Rights Reserved.
 * 
 **************************************************************************/

/*
 * filter.c - Routines to filter MIDI events.
 */

#include <windows.h>
#include "midimon.h"
#include "display.h"
#include "filter.h"

/* CheckEventFilter - Checks the given EVENT against the given FILTER.
 *      
 * Params:  lpEvent - Points to an EVENT.
 *          lpFilter - Points to a FILTER structure.
 *
 * Return:  Returns 1 if the event is filtered, 0 if it is not filtered.
 */
BOOL CheckEventFilter(LPEVENT lpEvent, LPFILTER lpFilter)
{
    BYTE bStatus, bStatusRaw, bChannel, bData1, bData2;

    /* Get the essential info from the EVENT.
     */
    bStatusRaw = LOBYTE(LOWORD(lpEvent->data));
    bStatus = bStatusRaw & (BYTE) 0xf0;
    bChannel = LOBYTE(LOWORD(lpEvent->data)) & (BYTE) 0x0f;
    bData1 = HIBYTE(LOWORD(lpEvent->data));
    bData2 = LOBYTE(HIWORD(lpEvent->data));

    /* Do channel filtering for all but system events.
     */
    if(bStatus != SYSTEMMESSAGE){
        if(lpFilter->channel[bChannel])
            return 1;
    }

    /* Do event-type filtering.
     */
    switch(bStatus){
        case NOTEOFF:
            if(lpFilter->event.noteOff)
                return 1;
            break;

        case NOTEON:
            /* A note on with a velocity of 0 is a note off.
             */
            if(bData2 == 0){
                if(lpFilter->event.noteOff)
                    return 1;
                break;
            }
            
            if(lpFilter->event.noteOn)
                return 1;
            break;

        case KEYAFTERTOUCH:
            if(lpFilter->event.keyAftertouch)
                return 1;
            break;

        case CONTROLCHANGE:
            if(lpFilter->event.controller)
                return 1;
            
            /* Channel mode messages can be filtered.
             */
            if((bData1 >= 121) && lpFilter->event.channelMode)
                return 1;
            break;

        case PROGRAMCHANGE:
            if(lpFilter->event.progChange)
                return 1;
            break;

        case CHANAFTERTOUCH:
            if(lpFilter->event.chanAftertouch)
                return 1;
            break;

        case PITCHBEND:
            if(lpFilter->event.pitchBend)
                return 1;
            break;

        case SYSTEMMESSAGE:
            /* System common messages.
             */
            if((bStatusRaw < 0xf8) && (lpFilter->event.sysCommon))
                return 1;

            /* Active sensing messages.
             */
            if((bStatusRaw == 0xfe) && (lpFilter->event.activeSense))
                return 1;

            /* System real time messages.
             */
            if((bStatusRaw >= 0xf8) && lpFilter->event.sysRealTime)
                return 1;
            break;

        default:
            break;
    }

    return 0;
}
