// A sequence of two-column ranges waits on the stage.
// So long as the page's skeleton hasn't changed--that is, the maximum height
// available to the two-column chunk is the same--we just use the columns that
// have been built up so far, and choose a column into which to put the stage.
// If the skeleton has changed, however, then we may need to make entirely
// new decisions about which column gets what, so we recompose the whole page.
void multicol::tryout()
{
if (htavail == prevhtavail)
choosecol(currpage->stage, htavail);
else
currpage->compose(DRAFT);
prevhtavail = htavail;
}
// Try, very hard, to put everything in the multicol into two columns
// so that the total height is at most htavail.
void multicol::compose(int defonly)
{
int i;
stream cd;
if (!nonempty()) {
setheight(0);
return;
}
scratch.freeall(); // fill scratch with everything destined
// for either column
for (cd = definite; cd.more(); cd.advance())
scratch.append(cd.current());
if (!defonly)
for (cd = *(currpage->stage); cd.more(); cd.advance())
if (cd.current()->numcol() == 2)
scratch.append(cd.current());
scratch.restoreall(); // in particular, floatables' goals
int rawht = scratch.rawht();
int halfheight = (int)(coltol*rawht);
// choose a goal height
int maxht = defonly ? halfheight : htavail;
secondtry:
for (i = 0; i < 2; i++)
column[i].freeall();
leftblocked = 0;
cd = scratch;
while (cd.more()) {
queue ministage; // for the minimally acceptable chunks
ministage.freeall(); // that are to be added to either column
while (cd.more() && !cd.current()->issentinel()) {
ministage.enqueue(cd.current());
cd.advance();
}
choosecol(&ministage, maxht);
if (cd.more() && cd.current()->issentinel())
cd.advance(); // past sentinel
}
if (height() > htavail && maxht != htavail) {
// We tried to balance the columns, but
// the result was too tall. Go back
// and try again with the less ambitious
// goal of fitting the space available.
maxht = htavail;
goto secondtry;
}
for (i = 0; i < 2; i++) {
movefloats(&(column[i]), ((double) column[i].rawht())/currpage->pagesize);
trimspace(&(column[i]));
}
if (dbg & 32) {
printf("#multicol::compose: htavail %d maxht %d dv %d\n",
htavail, maxht, height());
dump();
}
if (defonly)
stretch(height());
}
static int search(struct dlx *solver, int k) {
/* if (k == 21) */
/* return 1; */
int solutions = 0;
/* printf("k = %d\n", k); */
struct node *r, *j;
if (solver->h.next == &solver->h) {
printsoln(solver, k);
return 1;
}
struct column *c = choosecol(solver);
if (c->len == 0) {
printf("X\n");
uncover(solver, c);
return 0;
}
/* printf("CHOOSE %s\n", c->name); */
int xx = cover(solver, c);
if (xx) {
printf("Got a zero\n");
return 0;
}
for (r = c->node.d; r != &c->node; r = r->d) {
solver->solnodes[k] = r;
for (j = r->r; j != r; j = j->r) {
cover(solver, j->c);
}
int rc = search(solver, k+1);
solutions += search(solver, k+1);
if (k == 0) {
printf("Solutions increased by %d to %d\n", rc, solutions);
}
for (j = r->l; j != r; j = j->l) {
uncover(solver, j->c);
}
if (solutions >= 1)
break;
}
uncover(solver, c);
return solutions;
}