hashmap: improve struct hashmap member documentation

diff --git a/commit-slab.h b/commit-slab.h
index d068e2d5316c93cd5120d56cfd146a34b9fe2913..375c9c751adbf165c757832667102b761e1358c3 100644 (file)
--- a/commit-slab.h
+++ b/commit-slab.h
@@ -91,7 +91,7 @@ static MAYBE_UNUSED elemtype *slabname## _at(struct slabname *s,      \
        if (s->slab_count <= nth_slab) {                                \
                int i;                                                  \
                s->slab = xrealloc(s->slab,                             \
-                                  (nth_slab + 1) * sizeof(s->slab));   \
+                                  (nth_slab + 1) * sizeof(*s->slab));  \
                stat_ ##slabname## realloc++;                           \
                for (i = s->slab_count; i <= nth_slab; i++)             \
                        s->slab[i] = NULL;                              \
@@ -117,4 +117,16 @@ static int stat_ ##slabname## realloc
  * catch because GCC silently parses it by default.
  */
 
+/*
+ * Statically initialize a commit slab named "var". Note that this
+ * evaluates "stride" multiple times! Example:
+ *
+ *   struct indegree indegrees = COMMIT_SLAB_INIT(1, indegrees);
+ *
+ */
+#define COMMIT_SLAB_INIT(stride, var) { \
+       COMMIT_SLAB_SIZE / sizeof(**((var).slab)) / (stride), \
+       (stride), 0, NULL \
+}
+
 #endif /* COMMIT_SLAB_H */