clarify scan_content() logic for choosing encoding

diff --git a/uip/mhbuildsbr.c b/uip/mhbuildsbr.c
index 3429c1efefd2759eebe2098815936e538dfa3d35..a05b4cbf068ff4f97868b230524606b4c02e3bcb 100644 (file)
--- a/uip/mhbuildsbr.c
+++ b/uip/mhbuildsbr.c
@@ -1493,24 +1493,30 @@ scan_content (CT ct, size_t maxunencoded)
 
     if (ct->c_reqencoding != CE_UNKNOWN)
        ct->c_encoding = ct->c_reqencoding;
-    else
+    else {
+       int wants_q_p = (containsnul || linelen || linespace || checksw);
+
        switch (ct->c_type) {
        case CT_TEXT:
-           if (contains8bit && !containsnul && !linelen && !linespace && !checksw)
-               ct->c_encoding = CE_8BIT;
-           else if (contains8bit || containsnul || linelen || linespace || checksw)
-               ct->c_encoding = CE_QUOTED;
-           else
-               ct->c_encoding = CE_7BIT;
+            if (wants_q_p)
+                 ct->c_encoding = CE_QUOTED;
+            else if (contains8bit)
+                 ct->c_encoding = CE_8BIT;
+            else
+                 ct->c_encoding = CE_7BIT;
+
            break;
 
        case CT_APPLICATION:
            /* For application type, use base64, except when postscript */
-           if (containsnul || contains8bit || linelen || linespace || checksw)
-               ct->c_encoding = (ct->c_subtype == APPLICATION_POSTSCRIPT)
-                   ? CE_QUOTED : CE_BASE64;
-           else
+           if (wants_q_p || contains8bit) {
+               if (ct->c_subtype == APPLICATION_POSTSCRIPT)
+                   ct->c_encoding = CE_QUOTED;  // historical
+               else
+                   ct->c_encoding = CE_BASE64;
+           } else {
                ct->c_encoding = CE_7BIT;
+           }
            break;
 
        case CT_MESSAGE:
@@ -1524,6 +1530,7 @@ scan_content (CT ct, size_t maxunencoded)
            ct->c_encoding = CE_BASE64;
            break;
         }
+    }
 
     return (boundaryclash ? NOTOK : OK);
 }