From b10b254860b2bcbc85b9779a2388d33ce8318908 Mon Sep 17 00:00:00 2001
From: Matthew Fernandez <matthew.fernandez@gmail.com>
Date: Sat, 3 Dec 2022 10:54:23 -0800
Subject: [PATCH] patchwork: replace clist implementation with generic list

This replaces some common/memory.h allocations with cgraph/alloc.h, but more
importantly reduces the amount of code to maintain here. Note that confusingly
the list begins with a NULL entry and is only relevant to store later if we have
accrued more than just the initial NULL.
---
 lib/patchwork/patchworkinit.c | 42 +++++++++++++----------------------
 1 file changed, 15 insertions(+), 27 deletions(-)

diff --git a/lib/patchwork/patchworkinit.c b/lib/patchwork/patchworkinit.c
index 5385e193f..b4955af7a 100644
--- a/lib/patchwork/patchworkinit.c
+++ b/lib/patchwork/patchworkinit.c
@@ -8,7 +8,10 @@
  * Contributors: Details at https://graphviz.org
  *************************************************************************/
 
+#include    <assert.h>
+#include    <cgraph/list.h>
 #include    <patchwork/patchwork.h>
+#include    <limits.h>
 #include    <neatogen/adjust.h>
 #include    <pack/pack.h>
 #include    <neatogen/neatoprocs.h>
@@ -17,29 +20,7 @@
 /* the following code shamelessly copied from lib/fdpgen/layout.c
 and should be extracted and made into a common function */
 
-#define CL_CHUNK 10
-
-typedef struct {
-    graph_t **cl;
-    int sz;
-    int cnt;
-} clist_t;
-
-/* addCluster:
- * Append a new cluster to the list.
- * NOTE: cl[0] is empty. The clusters are in cl[1..cnt].
- * Normally, we increase the array when cnt == sz.
- * The test for cnt > sz is necessary for the first time.
- */
-static void addCluster(clist_t * clist, graph_t * subg)
-{
-    clist->cnt++;
-    if (clist->cnt >= clist->sz) {
-	clist->sz += CL_CHUNK;
-	clist->cl = RALLOC(clist->sz, clist->cl, graph_t *);
-    }
-    clist->cl[clist->cnt] = subg;
-}
+DEFINE_LIST(clist, graph_t*)
 
 /* mkClusters:
  * Attach list of immediate child clusters.
@@ -56,6 +37,8 @@ mkClusters (graph_t * g, clist_t* pclist, graph_t* parent)
     clist_t* clist;
 
     if (pclist == NULL) {
+        // [0] is empty. The clusters are in [1..cnt].
+        clist_append(&list, NULL);
         clist = &list;
     }
     else
@@ -70,7 +53,7 @@ mkClusters (graph_t * g, clist_t* pclist, graph_t* parent)
             LEVEL(subg) = LEVEL(parent) + 1;
             GPARENT(subg) = parent;
 #endif
-            addCluster(clist, subg);
+            clist_append(clist, subg);
             mkClusters(subg, NULL, subg);
         }
         else {
@@ -78,9 +61,14 @@ mkClusters (graph_t * g, clist_t* pclist, graph_t* parent)
         }
     }
     if (pclist == NULL) {
-        GD_n_cluster(g) = list.cnt;
-        if (list.cnt)
-            GD_clust(g) = RALLOC(list.cnt + 1, list.cl, graph_t*);
+        assert(clist_size(&list) - 1 <= INT_MAX);
+        GD_n_cluster(g) = (int)(clist_size(&list) - 1);
+        if (clist_size(&list) > 1) {
+            clist_shrink_to_fit(&list);
+            GD_clust(g) = clist_detach(&list);
+        } else {
+            clist_free(&list);
+        }
     }
 }
 
-- 
2.40.0