Index: aocutils.c
==================================================================
--- aocutils.c
+++ aocutils.c
@@ -42,11 +42,11 @@
     int ch;
     char *tmp = malloc(512);
     size_t s = 512;
     size_t r = 0;
     while ((ch = fgetc(h)) != EOF) {
-        if (r == s) {
+        if (r+1 == s) {
             // grow the array (by golden ratio)
             char *ttmp = realloc(tmp, (13*s) / 8);
             if (ttmp) {
                 tmp = ttmp;
                 s = (13*s) / 8;
@@ -56,10 +56,11 @@
             }
         }
         tmp[r++] = ch;
     }
     fclose(h);
+    tmp[r] = 0;
     *dst = tmp;
 
     return r;
 }