1 files changed, 8 insertions, 16 deletions
diff --git a/src/base/string/appendf.c b/src/base/string/appendf.c
index 4b8d76c..dee2065 100644
--- a/src/base/string/appendf.c
+++ b/src/base/string/appendf.c
@@ -6,26 +6,18 @@
  */
 
 int
-str·appendf(string *s, const byte* fmt, ...)
+string·appendf(string *s, byte* fmt, ...)
 {
+    int r, n;
     va_list args;
+
     va_start(args, fmt);
-    int remain = str·cap(*s) - str·len(*s);
-    int n      = vsnprintf(*s + str·len(*s), remain + 1, fmt, args);
+    do{
+        r = string·cap(*s) - string·len(*s);
+        n = fmt·vnsprint(*s + string·len(*s), r+1, fmt, args);
+        string·grow(s, 2*string·cap(*s));
+    }while(n==r);
     va_end(args);
 
-    if(n > remain){
-        // If the first write was incomplete, we overwite the data again.
-        str·grow(s, n);
-        va_list args;
-        va_start(args, fmt);
-        n = vsnprintf(*s + str·len(*s), n + 1, fmt, args);
-        assert(n - remain <= str·cap(*s));
-        va_end(args);
-    }
-
-    Hdr* h = (Hdr*)(*s - sizeof(Hdr));
-    h->len += n;
-
     return n;
 }