src/auths/xtextencode.c

   1 /*************************************************
   2 *     Exim - an Internet mail transport agent    *
   3 *************************************************/
   4
   5 /* Copyright (c) University of Cambridge 1995 - 2009 */
   6 /* See the file NOTICE for conditions of use and distribution. */
   7
   8 #include "../exim.h"
   9
  10
  11 /*************************************************
  12 *          Encode byte-string in xtext           *
  13 *************************************************/
  14
  15 /* This function encodes a string of bytes, containing any values whatsoever,
  16 as "xtext", as defined in RFC 1891 and required by the SMTP AUTH extension (RFC
  17 2554).
  18
  19 Arguments:
  20   clear       points to the clear text bytes
  21   len         the number of bytes to encode
  22
  23 Returns:      a pointer to the zero-terminated xtext string, which
  24               is in working store
  25 */
  26
  27 uschar *
  28 auth_xtextencode(uschar *clear, int len)
  29 {
  30 uschar *code;
  31 uschar *p = (uschar *)clear;
  32 uschar *pp;
  33 int c = len;
  34 int count = 1;
  35 register int x;
  36
  37 /* We have to do a prepass to find out how many specials there are,
  38 in order to get the right amount of store. */
  39
  40 while (c -- > 0)
  41   count += ((x = *p++) < 33 || x > 127 || x == '+' || x == '=')? 3 : 1;
  42
  43 pp = code = store_get(count);
  44
  45 p = (uschar *)clear;
  46 c = len;
  47 while (c-- > 0)
  48   {
  49   if ((x = *p++) < 33 || x > 127 || x == '+' || x == '=')
  50     {
  51     sprintf(CS pp, "+%.02x", x);   /* There's always room */
  52     pp += 3;
  53     }
  54   else *pp++ = x;
  55   }
  56
  57 *pp = 0;
  58 return code;
  59 }
  60
  61 /* End of xtextencode.c */