tal: add tal_expand().

[ccan] / ccan / tal / tal.c

diff --git a/ccan/tal/tal.c b/ccan/tal/tal.c
index 4f7d56784dd9f2ffb46131f98b7f6288981d1c62..5c0aec07990dcbafc44b5e7bf075ac8c68ba5641 100644 (file)
--- a/ccan/tal/tal.c
+++ b/ccan/tal/tal.c
@@ -712,6 +712,37 @@ bool tal_resize_(tal_t **ctxp, size_t size, size_t count)
        return true;
 }
 
+bool tal_expand_(tal_t **ctxp, const void *src, size_t size, size_t count)
+{
+       struct length *l;
+       bool ret = false;
+
+       l = find_property(debug_tal(to_tal_hdr(*ctxp)), LENGTH);
+
+       /* Check for additive overflow */
+       if (l->count + count < count) {
+               call_error("dup size overflow");
+               goto out;
+       }
+
+       /* Don't point src inside thing we're expanding! */
+       assert(src < *ctxp
+              || (char *)src >= (char *)(*ctxp) + (size * l->count));
+
+       /* Note: updates l->count. */
+       if (!tal_resize_(ctxp, size, l->count + count))
+               goto out;
+
+       memcpy((char *)*ctxp + size * (l->count - count),
+              src, count * size);
+       ret = true;
+
+out:
+       if (taken(src))
+               tal_free(src);
+       return ret;
+}
+
 void *tal_dup_(const tal_t *ctx, const void *p, size_t size,
               size_t n, size_t extra, bool add_count,
               const char *label)