tree234: avoid an uninitialised-variable warning.

Apparently, some compilers can't work out that the pattern

  if (!t->root) { special-case handler followed by early return }
  n = t->root;
  while (n) { ... }

will execute the while loop at least once, on the grounds that the
_first_ test for n being non-NULL must pass, because we initialised n
from t->root which can't be NULL on any code path where we didn't take
the early return. So they might give an uninitialised-variable warning
for the variable 'ki', which is initialised inside the while loop.

Compilers, eh. But it's easy enough to turn the while into a do-while,
so that even the least alert compiler will know it runs at least once.

1 files changed, 2 insertions, 2 deletions

diff --git a/tree234.c b/tree234.c
index 136f6e2..1cdae9f 100644
--- a/tree234.c
+++ b/tree234.c
@@ -332,7 +332,7 @@ static void *add234_internal(tree234 *t, void *e, int index) {
     }
 
     n = t->root;
-    while (n) {
+    do {
 	LOG(("  node %p: %p/%d \"%s\" %p/%d \"%s\" %p/%d \"%s\" %p/%d\n",
 	     n,
 	     n->kids[0], n->counts[0], n->elems[0],
@@ -385,7 +385,7 @@ static void *add234_internal(tree234 *t, void *e, int index) {
 	if (!n->kids[ki])
 	    break;
 	n = n->kids[ki];
-    }
+    } while (n);
 
     add234_insert(NULL, e, NULL, &t->root, n, ki);