radix-tree: fix bug when erasing elts in remove_prefix

_erase_elt() now zeroes the last element of the array (ie. sets to
UNSET).  Previously remove() was doing this, but not remove_prefix().

diff --git a/base/data-struct/radix-tree.c b/base/data-struct/radix-tree.c
index 202d463d2cfa2854ca4c815a4579bf201b6b7760..ffbf029f7d514537cab9b3716022b6227496b7af 100644 (file)
--- a/base/data-struct/radix-tree.c
+++ b/base/data-struct/radix-tree.c
@@ -626,6 +626,9 @@ static void _erase_elt(void *array, unsigned obj_size, unsigned count, unsigned
        memmove(((uint8_t *) array) + (obj_size * index),
                 ((uint8_t *) array) + (obj_size * (index + 1)),
                 obj_size * (count - index - 1));
+
+       // Zero the now unused last elt (set's v.type to UNSET)
+       memset(array + (count - 1) * obj_size, 0, obj_size);
 }
 
 static bool _remove(struct radix_tree *rt, struct value *root, uint8_t *kb, uint8_t *ke)
@@ -700,7 +703,6 @@ static bool _remove(struct radix_tree *rt, struct value *root, uint8_t *kb, uint
                                        }
 
                                        n4->nr_entries--;
-                                       n4->values[n4->nr_entries].type = UNSET;
                                        if (!n4->nr_entries) {
                                                free(n4);
                                                root->type = UNSET;
@@ -723,7 +725,6 @@ static bool _remove(struct radix_tree *rt, struct value *root, uint8_t *kb, uint
                                        }
 
                                        n16->nr_entries--;
-                                       n16->values[n16->nr_entries].type = UNSET;
                                        if (n16->nr_entries <= 4) {
                                                _degrade_to_n4(n16, root);
                                        }
@@ -745,7 +746,6 @@ static bool _remove(struct radix_tree *rt, struct value *root, uint8_t *kb, uint
                                                n48->keys[j]--;
                                _erase_elt(n48->values, sizeof(*n48->values), n48->nr_entries, i);
                                n48->nr_entries--;
-                               n48->values[n48->nr_entries].type = UNSET;
                                if (n48->nr_entries <= 16)
                                        _degrade_to_n16(n48, root);
                        }
@@ -1066,7 +1066,7 @@ static bool _check_nodes(struct value *v, unsigned *count)
 
                for (i = n4->nr_entries; i < 4; i++)
                        if (n4->values[i].type != UNSET) {
-                               fprintf(stderr, "unused value is not UNSET\n");
+                               fprintf(stderr, "unused value is not UNSET (n4)\n");
                                return false;
                        }
 
@@ -1080,7 +1080,7 @@ static bool _check_nodes(struct value *v, unsigned *count)
 
                for (i = n16->nr_entries; i < 16; i++)
                        if (n16->values[i].type != UNSET) {
-                               fprintf(stderr, "unused value is not UNSET\n");
+                               fprintf(stderr, "unused value is not UNSET (n16)\n");
                                return false;
                        }
 
@@ -1105,7 +1105,7 @@ static bool _check_nodes(struct value *v, unsigned *count)
 
                for (i = n48->nr_entries; i < 48; i++)
                        if (n48->values[i].type != UNSET) {
-                               fprintf(stderr, "unused value is not UNSET\n");
+                               fprintf(stderr, "unused value is not UNSET (n48)\n");
                                return false;
                        }