/**
 ** modewalk.c ---- utilities to iterate over the available video modes
 **
 ** Copyright (c) 1995 Csaba Biegl, 820 Stirrup Dr, Nashville, TN 37221
 ** [e-mail: csaba@vuse.vanderbilt.edu]
 **
 ** This file is part of the GRX graphics library.
 **
 ** The GRX graphics library is free software; you can redistribute it
 ** and/or modify it under some conditions; see the "copying.grx" file
 ** for details.
 **
 ** This library is distributed in the hope that it will be useful,
 ** but WITHOUT ANY WARRANTY; without even the implied warranty of
 ** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 **
 **/

#include "grdriver.h"
#include "libgrx.h"

static GrVideoMode *modewalk(GrVideoMode *pm,GrVideoMode *dup,GrFrameMode md)
{
	GrVideoDriver *vd;
	GrVideoMode   *vm;
	int n,seen = TRUE;
	if(pm && pm->extinfo) {
	    md   = pm->extinfo->mode;
	    seen = FALSE;
	}
	for(vd = VDRV; vd != NULL; vd = vd->inherit) {
	    for(n = vd->nmodes,vm = vd->modes; --n >= 0; vm++) {
	    	if(vm->present == FALSE)    continue;
	    	if(vm->extinfo == NULL)     continue;
	    	if(vm->extinfo->mode != md) continue;
	    	if(dup) {
	    	    if(vm == dup) return(NULL);
	    	    if(vm->width  != dup->width)  continue;
	    	    if(vm->height != dup->height) continue;
	    	    if(vm->bpp    != dup->bpp)    continue;
	    	    return(vm);
	    	}
	    	if(seen) {
	    	    if(!modewalk(NULL,vm,md)) return(vm);
	    	    continue;
	    	}
	    	if(pm == vm) {
	    	    seen = TRUE;
	    	}
	    }
	}
	return(NULL);
}
	    	
const GrVideoMode *GrFirstVideoMode(GrFrameMode fmode)
{
	return(modewalk(NULL,NULL,fmode));
}
	
const GrVideoMode *GrNextVideoMode(const GrVideoMode *prev)
{
	return(modewalk((GrVideoMode *)prev,NULL,GR_frameUndef));
}