neatogen mkOverlapSet: return actual point count in 'cntp'

For reasons unclear to me, the `mkOverlapSet` function was constructing a set of
points with an implicit initial 0 point and then notifying the caller of a count
1 _less_ than the total point count. There was nothing wrong with this, but it
led to several instances of non-idiomatic follow-on code that had to account for
an array that was actually 1 longer than what its count variable said.

diff --git a/lib/neatogen/constraint.c b/lib/neatogen/constraint.c
index 5658515a5fb3740fbbc98f05a6b79d64d7532a15..d0cd890772b7f5fe59f574c4f6503c10b0cc064e 100644 (file)
--- a/lib/neatogen/constraint.c
+++ b/lib/neatogen/constraint.c
@@ -691,10 +691,12 @@ static double compress(info * nl, int nn)
 static pointf *mkOverlapSet(info *nl, size_t nn, size_t *cntp) {
     info *p = nl;
     info *q;
-    size_t sz = nn;
-    pointf *S = N_GNEW(sz + 1, pointf);
+    size_t sz = nn + 1;
+    pointf *S = N_GNEW(sz, pointf);
     size_t cnt = 0;
 
+    S[cnt++] = (pointf){0};
+
     for (size_t i = 0; i < nn; i++) {
        q = p + 1;
        for (size_t j = i + 1; j < nn; j++) {
@@ -702,7 +704,7 @@ static pointf *mkOverlapSet(info *nl, size_t nn, size_t *cntp) {
                pointf pt;
                if (cnt == sz) {
                    sz += nn;
-                   S = RALLOC(sz + 1, S, pointf);
+                   S = RALLOC(sz, S, pointf);
                }
                if (p->pos.x == q->pos.x)
                    pt.x = HUGE_VAL;
@@ -718,14 +720,14 @@ static pointf *mkOverlapSet(info *nl, size_t nn, size_t *cntp) {
                    if (pt.y < 1)
                        pt.y = 1;
                }
-               S[++cnt] = pt;
+               S[cnt++] = pt;
            }
            q++;
        }
        p++;
     }
 
-    S = RALLOC(cnt + 1, S, pointf);
+    S = RALLOC(cnt, S, pointf);
     *cntp = cnt;
     return S;
 }
@@ -737,12 +739,12 @@ static pointf computeScaleXY(pointf *aarr, size_t m) {
 
     aarr[0].x = 1;
     aarr[0].y = HUGE_VAL;
-    qsort(aarr + 1, m, sizeof(pointf), (sortfn_t) sortf);
+    qsort(aarr + 1, m - 1, sizeof(pointf), (sortfn_t)sortf);
 
-    barr = N_GNEW(m + 1, pointf);
-    barr[m].x = aarr[m].x;
-    barr[m].y = 1;
-    for (size_t k = m - 1; m > 0; k--) {
+    barr = N_GNEW(m, pointf);
+    barr[m - 1].x = aarr[m - 1].x;
+    barr[m - 1].y = 1;
+    for (size_t k = m - 2; m > 1; k--) {
        barr[k].x = aarr[k].x;
        barr[k].y = MAX(aarr[k + 1].y, barr[k + 1].y);
        if (k == 0) {
@@ -752,7 +754,7 @@ static pointf computeScaleXY(pointf *aarr, size_t m) {
 
     size_t best = 0;
     bestcost = HUGE_VAL;
-    for (size_t k = 0; k <= m; k++) {
+    for (size_t k = 0; k < m; k++) {
        cost = barr[k].x * barr[k].y;
        if (cost < bestcost) {
            bestcost = cost;
@@ -777,7 +779,7 @@ static double computeScale(pointf *aarr, size_t m) {
     pointf p;
 
     aarr++;
-    for (size_t i = 1; i <= m; i++) {
+    for (size_t i = 1; i < m; i++) {
        p = *aarr++;
        v = MIN(p.x, p.y);
        if (v > sc)