extol.c: add file size limit

c-programming/jokes/extol.c

@@ -16,12 +16,15 @@ enum
 } EXTOL_MODE;
 
 #define EXTOL_PROTOTYPE "int extol(FILE* f)"
+#define EXTOL_FILE_NAME "extol.txt"
+#define EXTOL_FILE_LIMIT 128
 
 int
 extol (FILE *f)
 {
   static bool spec_run = true;
   int result;
+  off_t size;
 
   if (spec_run == false)
     {
@@ -38,6 +41,21 @@ extol (FILE *f)
           exit (EXIT_FAILURE);
         }
       fseek (fs, 0L, SEEK_END);
+      size = ftello (fs);
+      if (size == -1)
+        {
+          perror ("ftello");
+          exit (EXIT_FAILURE);
+        }
+      else if (size > EXTOL_FILE_LIMIT)
+        {
+          FILE *new_fs = freopen (EXTOL_FILE_NAME, "w", fs);
+          if (new_fs == NULL)
+            {
+              perror ("freopen");
+              exit (EXIT_FAILURE);
+            }
+        }
       result = extol (fs);
       for (result <<= 4, result &= ~15; (result & 15) != 15; result++)
         fputc ('=', fs);