From: Ken Hornstein <kenh@pobox.com>
Date: Mon, 21 Oct 2013 20:01:02 +0000 (-0400)
Subject: Start of RFC 2047 encoding code.  Not complete in the slightest.
X-Git-Url: https://diplodocus.org/git/nmh/commitdiff_plain/b776e28b89aa117da6d93888813aa52b2c292d02?ds=inline

Start of RFC 2047 encoding code.  Not complete in the slightest.
---

diff --git a/h/prototypes.h b/h/prototypes.h
index 0df91b1d..e94bee36 100644
--- a/h/prototypes.h
+++ b/h/prototypes.h
@@ -59,6 +59,27 @@ char *cpytrim (const char *);
 int decode_rfc2047 (char *, char *, size_t);
 void discard (FILE *);
 int default_done (int);
+
+/*
+ * Encode a message header using RFC 2047 encoding.  If the message contains
+ * no non-ASCII characters, then leave the header as-is.
+ *
+ * Arguments include:
+ *
+ * name		- Message header name
+ * value	- Message header content; must point to allocated memory
+ *		  (may be changed if encoding is necessary)
+ * encoding	- Encoding type.  May be one of CE_UNKNOWN (function chooses
+ *		  the encoding), CE_BASE64 or CE_QUOTED
+ * charset	- Charset used for encoding.  If NULL, obtain from system
+ *		  locale.
+ *
+ * Returns 0 on success, any other value on failure.
+ */
+
+int encode_rfc2047(const char *name, char **value, int encoding,
+		   const char *charset);
+
 void escape_display_name (char *, size_t);
 void escape_local_part (char *, size_t);
 int ext_hook(char *, char *, char *);
diff --git a/sbr/encode_rfc2047.c b/sbr/encode_rfc2047.c
new file mode 100644
index 00000000..ff77ff52
--- /dev/null
+++ b/sbr/encode_rfc2047.c
@@ -0,0 +1,43 @@
+/*
+ * Routines to encode message headers using RFC 2047-encoding.
+ *
+ * This code is Copyright (c) 2002, by the authors of nmh.  See the
+ * COPYRIGHT file in the root directory of the nmh distribution for
+ * complete copyright information.
+ */
+
+#include <h/mh.h>
+
+/*
+ * Encode a message header using RFC 2047 encoding.  We make the assumption
+ * that all characters < 128 are ASCII and as a consequence don't need any
+ * encoding.
+ */
+
+int
+encode_rfc2047(const char *name, char **value, int encoding,
+	       const char *charset)
+{
+    char *p;
+
+    /*
+     * First, check to see if we even need to encode the header
+     */
+
+    for (p = *value; *p != '\0'; p++) {
+	if (! isascii((int) *p)
+	    goto encode;
+    }
+
+    return 0;
+
+encode:
+    /*
+     * Some rules from RFC 2047:
+     *
+     * - Encoded words cannot be more than 75 characters long
+     * - Multiple "long" encoded words must be on new lines.
+     *
+     * Also, we're not permitted to encode email addresses, so
+     * we need to actually _parse_ email addresses and only encode
+     * the right bits.