/*
 * smallfactors - find the factors of a number < 2^32
 *
 * Copyright (C) 2013 Christoph Zurnieden
 *
 * Calc is open software; you can redistribute it and/or modify it under
 * the terms of the version 2.1 of the GNU Lesser General Public License
 * as published by the Free Software Foundation.
 *
 * Calc 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.  See the GNU Lesser General
 * Public License for more details.
 *
 * A copy of version 2.1 of the GNU Lesser General Public License is
 * distributed with calc under the filename COPYING-LGPL.  You should have
 * received a copy with calc; if not, write to Free Software Foundation, Inc.
 * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */


static resource_debug_level;
resource_debug_level = config("resource_debug", 0);


define smallfactors(x0)
{
    local d q x flist tuple w;

    if (x >= (2 ^ 32) - 1)
	return newerror("smallfactors: number must be < 2^32 -1");

    tuple = mat[2];
    flist = list();
    x = x0;
    d = 2;
    q = 0;
    tuple[0] = d;
    if (x < 2)
	return 0;
    do {
	q = x // d;
	    while (x == (q * d)) {
	    tuple[0] = d;
	    tuple[1]++;
	    x = floor(q);
	    q = x // d;
	}
	d = nextprime(d);
	if (tuple[1] > 0)
	    append(flist, tuple);
	tuple = mat[2];
    } while (d <= x);
    return flist;
}

define printsmallfactors(flist)
{
    local k;
    for (k = 0; k < size(flist); k++) {
	print flist[k][0]:"^":flist[k][1];
    }
}


config("resource_debug", resource_debug_level),;
if (config("resource_debug") & 3) {
    print "smallfactors(x0)";
    print "printsmallfactors(flist)";

}