/*
 * Revision Control Information
 *
 * $Source: /vol/opua/opua2/sis/sis-1.2/common/src/sis/network/RCS/cleanup.c,v $
 * $Author: sis $
 * $Revision: 1.5 $
 * $Date: 1993/08/03 00:18:52 $
 *
 */
#include "sis.h"


/*
 *  network_cleanup -- remove internal nodes with no fanout; this is iterated
 *  until every node has fanout > 0.
 */


int
network_cleanup(network)
network_t *network;
{
    int status, latch_removed;

    status = network_cleanup_util(network, 1, &latch_removed);
    if ((network->dc_network != NIL(network_t)) && latch_removed) {
	network_free(network->dc_network);
	network->dc_network = NIL(network_t);
    }
    return status;
}


int network_ccleanup(network)
network_t *network;
{
	return network_cleanup_util(network, 0, NIL(int));
}


int 
network_cleanup_util(network, sweep_latch, latch_removed)
network_t *network;
int sweep_latch;
int *latch_removed;
{
    node_t *p;
    int some_change, changed;
    lsGen gen;
#ifdef SIS
    latch_t *l;
    int i;
    node_t *out;
    node_t *in;
    node_t *dc_pi, *dc_po, *cnode, *fanout;
    lsGen gen2;
    node_t **fo_array;
#endif /* SIS */

    some_change = 0;
    if (latch_removed != NIL(int)) {
        *latch_removed = 0;
    }
    do {
	changed = 0;
	foreach_node(network, gen, p) {
	    if (p->type == INTERNAL && node_num_fanout(p) == 0) {
		network_delete_node_gen(network, gen);
		changed = 1;
		some_change = 1;
	    }
	}
#ifdef SIS
	if (sweep_latch) {
	  foreach_latch(network, gen, l) {
	    out = latch_get_output(l);
	    in = latch_get_input(l);
	    if (node_num_fanout(out) == 0) {
		/* Update the DC network.  If no nodes depend on this latch
                   output, then we can set it to an arbitrary constant in
                   the DC network. */
	    	if (network->dc_network != NIL(network_t)) {
		    dc_pi = network_find_node(network->dc_network, out->name);
		    if (dc_pi != NIL(node_t)) {
			cnode = node_constant(0);
			network_add_node(network->dc_network, cnode);
			fo_array = ALLOC(node_t *, node_num_fanout(dc_pi));
                	i = 0;
                	foreach_fanout(dc_pi, gen2, fanout) {
                    	    fo_array[i++] = fanout;
                	}
                	for (i = node_num_fanout(dc_pi); i-- > 0;) {
                    	    node_patch_fanin(fo_array[i], dc_pi, cnode);
                	}
                	FREE(fo_array);
                	network_delete_node(network->dc_network, dc_pi);
		    }
		    dc_po = network_find_node(network->dc_network, in->name);
               	    if (dc_po != NIL(node_t)) {
                	network_delete_node(network->dc_network, dc_po);
            	    }
		}
		network_delete_latch_gen(network, gen);
                network_delete_node(network, in);
	        network_delete_node(network, out);
		changed = 1;
		some_change = 1;
		if (latch_removed != NIL(int)) {
		    *latch_removed = 1;
		}
	    }
	  }
	}
#endif /* SIS */
		
    } while (changed);
    if (network->dc_network != NIL(network_t)) {
        (void) network_sweep(network->dc_network);
    }

    return some_change;
}