If you are applying this as a patch to your running mud, be sure to

BACK UP YOUR FILES FIRST

This is especially true, since the circlemud 3.5 code released
during december 2006 WILL RUIN YOUR HOUSE FILES and CORRUPT your
rent files. This is due to the introduction of ASCII rent files.
 
Unfortunately we were too eager to add what we thought was a
magnificent idea, and in the process forgot that people with
actual live running muds might use the code we provided.

Since the development has taken place on TBA, which has no players
as such, we failed to notice that the update was not thorough enough,
and several important additions were not added - for instance, a
house file and rent file converter tool. Also, it turned out, the
addition had severely hampered the object saving and loading routines,
to a point where items were being saved in an incompatible format
in houses.

Here is how to successfully convert your circlemud 3.1 house files,
step by step:

1) backup your house files somewhere not in the /lib/house folder
2) apply patch, debug, etc.
3) run the mud
4) now copy your house files back (while the mud is running!)
5) from within the mud, type "hcontrol asciiconvert" (without the quotes).
   This will give you some feedback about which houses are being processed.
6) shut down the mud
7) in lib/house, enter these commands:
    rm *.house            (you still have a backup of this, right ?)
    for i in *.ascii; do mv "$i" "${i/.ascii}"; done
8) start the mud - your houses now contain the right items.
9) feel free to remove code in house.c marked with CONVERSION tags.

src/house.c

@@ -45,6 +45,12 @@ ACMD(do_hcontrol);
 ACMD(do_house);
 
 
+// CONVERSION code starts here -- see comment below
+int ascii_convert_house(struct char_data *ch, obj_vnum vnum);
+void hcontrol_convert_houses(struct char_data *ch);
+struct obj_data *Obj_from_store(struct obj_file_elem object, int *location);
+// CONVERSION code ends here -- see comment below
+
 /* First, the basics: finding the filename; loading/saving objects */
 
 /* Return a filename given a house vnum */
@@ -70,7 +76,7 @@ int House_load(room_vnum vnum)
     return (0);
   if (!House_get_filename(vnum, filename, sizeof(filename)))
     return (0);
-  if (!(fl = fopen(filename, "r+b")))	/* no file found */
+  if (!(fl = fopen(filename, "r")))	/* no file found */
     return (0);
 
 	loaded = objsave_parse_objects(fl);
@@ -529,6 +535,11 @@ ACMD(do_hcontrol)
     hcontrol_pay_house(ch, arg2);
   else if (is_abbrev(arg1, "show"))
     hcontrol_list_houses(ch, arg2);
+// CONVERSION code starts here -- see comment below
+	// not in hcontrol_format
+	else if (!str_cmp(arg1, "asciiconvert"))
+    hcontrol_convert_houses(ch);
+// CONVERSION ends here -- read more below
   else
     send_to_char(ch, "%s", HCONTROL_FORMAT);
 }
@@ -641,3 +652,151 @@ void House_list_guests(struct char_data *ch, int i, int quiet)
   send_to_char(ch, "\r\n");
 }
 
+/* ***********************************************************************
+ * All code below this point and the code above, marked "CONVERSION"     *
+ * can be removed after you have converted your house rent files using   *
+ * the command                                                           *
+ *   hcontrol asciiconvert                                               *
+ *                                                                       *
+ * You can only use this command as implementor.                         *
+ * After you have converted your house files, I suggest a reboot, which  *
+ * will let your house files load on the next bootup.                    *
+ *                                                                       *
+ *                                                   Welcor              *
+ * ***********************************************************************/
+/*
+ * Code for conversion to ascii house rent files 
+ */
+
+void hcontrol_convert_houses(struct char_data *ch)
+{
+  int i;
+  
+	if (GET_LEVEL(ch) < LVL_IMPL)
+		{
+			send_to_char(ch, "Sorry, but you are not powerful enough to do that.\r\n");
+			return;
+		}
+
+
+  if (!num_of_houses) {
+    send_to_char(ch, "No houses have been defined.\r\n");
+    return;
+  }
+
+	send_to_char(ch, "Converting houses:\r\n");
+
+  for (i = 0; i < num_of_houses; i++) {
+	  send_to_char(ch, "  %d", house_control[i].vnum);
+	  
+	  if (!ascii_convert_house(ch, house_control[i].vnum))
+	  {	
+	  	// let ascii_convert_house() tell about the error
+	  	return;
+	  }
+	  else
+	  {
+	  	send_to_char(ch, "...done\r\n");
+	  } 
+  }
+	send_to_char(ch, "All done.\r\n");
+}
+
+
+int ascii_convert_house(struct char_data *ch, obj_vnum vnum)
+{
+	FILE *in, *out;
+	char infile[MAX_INPUT_LENGTH], *outfile;
+	struct obj_data *tmp;
+	int i, j=0;
+	
+  House_get_filename(vnum, infile, sizeof(infile));	
+	
+	CREATE(outfile, char, strlen(infile)+7);
+	sprintf(outfile, "%s.ascii", infile);
+	
+  if (!(in = fopen(infile, "r+b")))	/* no file found */
+  {
+  	send_to_char(ch, "...no object file found\r\n");
+  	free(outfile);
+    return (0);
+  }
+
+  if (!(out = fopen(outfile, "w")))
+  {
+  	send_to_char(ch, "...cannot open output file\r\n");
+		free(outfile);
+		fclose(in);
+    return (0);
+  }
+
+  while (!feof(in)) {
+    struct obj_file_elem object;
+    fread(&object, sizeof(struct obj_file_elem), 1, in);
+    if (ferror(in)) {
+      perror("SYSERR: Reading house file in House_load");
+      send_to_char(ch, "...read error in house rent file.\r\n");
+      free(outfile);
+      fclose(in);
+      fclose(out);
+      return (0);
+    }
+    if (!feof(in)) 
+    {
+    	tmp = Obj_from_store(object, &i);
+      if (!objsave_save_obj_record(tmp, out, i))
+      {
+	      send_to_char(ch, "...write error in house rent file.\r\n");
+	      free(outfile);
+	      fclose(in);
+	      fclose(out);
+	      return (0);
+      }
+      j++;
+    }
+  }
+	
+	fprintf(out, "$~\n");
+
+	fclose(in);
+	fclose(out);
+	
+	// copy the new file over the old one
+//  remove(infile);
+//  rename(outfile, infile);
+	
+	free(outfile);
+
+	send_to_char(ch, "...%d items", j);
+	return 1;
+}
+
+// the circle 3.1 function for reading rent files. No longer used by the rent system.
+struct obj_data *Obj_from_store(struct obj_file_elem object, int *location)
+{
+  struct obj_data *obj;
+  obj_rnum itemnum;
+  int j;
+
+  *location = 0;
+  if ((itemnum = real_object(object.item_number)) == NOTHING)
+    return (NULL);
+
+  obj = read_object(itemnum, REAL);
+#if USE_AUTOEQ
+  *location = object.location;
+#endif
+  GET_OBJ_VAL(obj, 0) = object.value[0];
+  GET_OBJ_VAL(obj, 1) = object.value[1];
+  GET_OBJ_VAL(obj, 2) = object.value[2];
+  GET_OBJ_VAL(obj, 3) = object.value[3];
+  GET_OBJ_EXTRA(obj) = object.extra_flags;
+  GET_OBJ_WEIGHT(obj) = object.weight;
+  GET_OBJ_TIMER(obj) = object.timer;
+  GET_OBJ_AFFECT(obj) = object.bitvector;
+
+  for (j = 0; j < MAX_OBJ_AFFECT; j++)
+    obj->affected[j] = object.affected[j];
+
+  return (obj);
+}