ean8: Require permitaddon to generate 2-/5-digit addons

Author: terryburton

CHANGES

@@ -1,3 +1,8 @@
+2025-04-09
+
+* The encoder for EAN-8 was changed to forbid the use of a two-digit or five-digit addon unless a permitaddon option is supplied.
+
+
 2025-03-14
 
 * The high-level encoder for MaxiCode was replaced with a new algorithm that may result in significantly shorter messages.

src/ean8.ps.src

@@ -57,6 +57,7 @@ begin
     /textxoffset 4.0 def
     /textyoffset -4.0 def
     /height 1.0 def
+    /permitaddon false def
     /addongap 12.0 def
     /addontextfont (unset) def
     /addontextsize null def
@@ -90,6 +91,9 @@ begin
     addon length 0 ne addon length 2 ne and addon length 5 ne and {
         /bwipp.ean8badAddOnLength (Add-on for EAN-8 must be 2 or 5 digits) //raiseerror exec
     } if
+    permitaddon not addon length 0 ne and {
+        /bwipp.ean8badAddOnLength (Non-standard use of add-on for EAN-8 requires "permitaddon" option) //raiseerror exec
+    } if
 
     % Add checksum digit
     /pad 8 string def