#include "copyright.h"

/* $XConsortium: XMaskEvent.c,v 11.18 88/09/06 16:11:31 jim Exp $ */
/* Copyright    Massachusetts Institute of Technology    1986	 */

#define NEED_EVENTS
#include "Xlibint.h"

extern _XQEvent *_qfree;
extern long _event_to_mask[];
#define AllPointers (PointerMotionMask|PointerMotionHintMask|ButtonMotionMask)
#define AllButtons (Button1MotionMask|Button2MotionMask|Button3MotionMask|\
		    Button4MotionMask|Button5MotionMask)

/*
 * return the next event in the queue matching one of the events in the mask.
 * If no event, flush output, and wait until match succeeds. Events earlier
 * in the queue are not discarded.
 */

XMaskEvent (dpy, mask, event)
  register Display *dpy;
  long mask;			/* Selected event mask. */
  register XEvent *event;	/* XEvent to be filled in. */
{
  register _XQEvent *prev, *qelt;

  LockDisplay (dpy);
  prev = NULL;
  while (1) {
    for (qelt = prev ? prev->next : dpy->head;
	 qelt;
	 prev = qelt, qelt = qelt->next) {
      if ((_event_to_mask[qelt->event.type] & mask) &&
	  ((qelt->event.type != MotionNotify) ||
	   (mask & AllPointers) ||
	   (mask & AllButtons & qelt->event.xmotion.state))) {
	*event = qelt->event;
	if (prev) {
	  if ((prev->next = qelt->next) == NULL)
	    dpy->tail = prev;
	}
	else {
	  if ((dpy->head = qelt->next) == NULL)
	    dpy->tail = NULL;
	}
	qelt->next = _qfree;
	_qfree = qelt;
	dpy->qlen--;
	UnlockDisplay (dpy);
	return;
      }
    }
    _XReadEvents (dpy);
  }
}