+/*************************************************
+* Exim - an Internet mail transport agent *
+*************************************************/
+
+/* Copyright (c) The Exim Maintainers 2022 - 2024 */
+/* Copyright (c) University of Cambridge 1995 - 2018 */
+/* See the file NOTICE for conditions of use and distribution. */
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#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 *
+xtextencode(uschar *clear, int len)
+{
+gstring * g = NULL;
+for(uschar ch; len > 0; len--, clear++)
+ g = (ch = *clear) < 33 || ch > 126 || ch == '+' || ch == '='
+ ? string_fmt_append(g, "+%.02X", ch)
+ : string_catn(g, clear, 1);
+gstring_release_unused(g);
+return string_from_gstring(g);
+}
+
+
+/*************************************************
+* Decode byte-string in xtext *
+*************************************************/
+
+/* This function decodes a string in xtextformat as defined in RFC 1891 and
+required by the SMTP AUTH extension (RFC 2554). We put the result in a piece of
+store of equal length - it cannot be longer than this. Although in general the
+result of decoding an xtext may be binary, in the context in which it is used
+by Exim (for decoding the value of AUTH on a MAIL command), the result is
+expected to be an addr-spec. We therefore add on a terminating zero, for
+convenience.
+
+Arguments:
+ code points to the coded string, zero-terminated
+ ptr where to put the pointer to the result, which is in
+ dynamic store
+
+Returns: the number of bytes in the result, excluding the final zero;
+ -1 if the input is malformed
+*/
+
+int
+xtextdecode(uschar * code, uschar ** ptr)
+{
+int x;
+uschar * result = store_get(Ustrlen(code) + 1, code);
+*ptr = result;
+
+while ((x = (*code++)) != 0)
+ {
+ if (x < 33 || x > 127 || x == '=') return -1;
+ if (x == '+')
+ {
+ register int y;
+ if (!isxdigit((x = (*code++)))) return -1;
+ y = ((isdigit(x))? x - '0' : (tolower(x) - 'a' + 10)) << 4;
+ if (!isxdigit((x = (*code++)))) return -1;
+ *result++ = y | ((isdigit(x))? x - '0' : (tolower(x) - 'a' + 10));
+ }
+ else *result++ = x;
+ }
+
+*result = 0;
+return result - *ptr;
+}
+
+/* End of xtextencode.c */
+/* vi: aw ai sw=2
+*/
git://git.exim.org / exim.git / commitdiff