1 files changed, 58 insertions, 0 deletions
diff --git a/src/auths/xtextencode.c b/src/auths/xtextencode.c
new file mode 100644
index 0000000..fc571c7
--- /dev/null
+++ b/src/auths/xtextencode.c
@@ -0,0 +1,58 @@
+/*************************************************
+*     Exim - an Internet mail transport agent    *
+*************************************************/
+
+/* Copyright (c) The Exim Maintainers 2022 */
+/* Copyright (c) University of Cambridge 1995 - 2018 */
+/* See the file NOTICE for conditions of use and distribution. */
+
+#include "../exim.h"
+
+
+/*************************************************
+*          Encode byte-string in xtext           *
+*************************************************/
+
+/* This function encodes a string of bytes, containing any values whatsoever,
+as "xtext", as defined in RFC 1891 and required by the SMTP AUTH extension (RFC
+2554).
+
+Arguments:
+  clear       points to the clear text bytes
+  len         the number of bytes to encode
+
+Returns:      a pointer to the zero-terminated xtext string, which
+              is in working store
+*/
+
+uschar *
+auth_xtextencode(uschar *clear, int len)
+{
+uschar *code;
+uschar *p = US clear;
+uschar *pp;
+int c = len;
+int count = 1;
+register int x;
+
+/* We have to do a prepass to find out how many specials there are,
+in order to get the right amount of store. */
+
+while (c -- > 0)
+  count += ((x = *p++) < 33 || x > 127 || x == '+' || x == '=')? 3 : 1;
+
+pp = code = store_get(count, clear);
+
+p = US clear;
+c = len;
+while (c-- > 0)
+  if ((x = *p++) < 33 || x > 127 || x == '+' || x == '=')
+    pp += sprintf(CS pp, "+%.02x", x);   /* There's always room */
+  else
+    *pp++ = x;
+
+*pp = 0;
+return code;
+}
+
+/* End of xtextencode.c */