external/ibm-public/postfix/dist/src/util/hex_quote.c

   1 /*      $NetBSD$        */
   2
   3 /*++
   4 /* NAME
   5 /*      hex_quote 3
   6 /* SUMMARY
   7 /*      quote/unquote text, HTTP style.
   8 /* SYNOPSIS
   9 /*      #include <hex_quote.h>
  10 /*
  11 /*      VSTRING *hex_quote(hex, raw)
  12 /*      VSTRING *hex;
  13 /*      const char *raw;
  14 /*
  15 /*      VSTRING *hex_unquote(raw, hex)
  16 /*      VSTRING *raw;
  17 /*      const char *hex;
  18 /* DESCRIPTION
  19 /*      hex_quote() takes a null-terminated string and replaces non-printable
  20 /*      and whitespace characters and the % by %XX, XX being the two-digit
  21 /*      hexadecimal equivalent.
  22 /*      The hexadecimal codes are produced as upper-case characters. The result
  23 /*      value is the hex argument.
  24 /*
  25 /*      hex_unquote() performs the opposite transformation. This function
  26 /*      understands lowercase, uppercase, and mixed case %XX sequences. The
  27 /*      result value is the raw argument in case of success, a null pointer
  28 /*      otherwise.
  29 /* BUGS
  30 /*      hex_quote() cannot process null characters in data.
  31 /* LICENSE
  32 /* .ad
  33 /* .fi
  34 /*      The Secure Mailer license must be distributed with this software.
  35 /* AUTHOR(S)
  36 /*      Wietse Venema
  37 /*      IBM T.J. Watson Research
  38 /*      P.O. Box 704
  39 /*      Yorktown Heights, NY 10598, USA
  40 /*--*/
  41
  42 /* System library. */
  43
  44 #include "sys_defs.h"
  45 #include <ctype.h>
  46
  47 /* Utility library. */
  48
  49 #include "msg.h"
  50 #include "vstring.h"
  51 #include "hex_quote.h"
  52
  53 /* Application-specific. */
  54
  55 #define STR(x)  vstring_str(x)
  56 #define LEN(x)  VSTRING_LEN(x)
  57
  58 /* hex_quote - raw data to quoted */
  59
  60 VSTRING *hex_quote(VSTRING *hex, const char *raw)
  61 {
  62     const char *cp;
  63     int     ch;
  64
  65     VSTRING_RESET(hex);
  66     for (cp = raw; (ch = *(unsigned const char *) cp) != 0; cp++) {
  67         if (ch != '%' && !ISSPACE(ch) && ISPRINT(ch)) {
  68             VSTRING_ADDCH(hex, ch);
  69         } else {
  70             vstring_sprintf_append(hex, "%%%02X", ch);
  71         }
  72     }
  73     VSTRING_TERMINATE(hex);
  74     return (hex);
  75 }
  76
  77 /* hex_unquote - quoted data to raw */
  78
  79 VSTRING *hex_unquote(VSTRING *raw, const char *hex)
  80 {
  81     const char *cp;
  82     int     ch;
  83
  84     VSTRING_RESET(raw);
  85     for (cp = hex; (ch = *cp) != 0; cp++) {
  86         if (ch == '%') {
  87             if (ISDIGIT(cp[1]))
  88                 ch = (cp[1] - '0') << 4;
  89             else if (cp[1] >= 'a' && cp[1] <= 'f')
  90                 ch = (cp[1] - 'a' + 10) << 4;
  91             else if (cp[1] >= 'A' && cp[1] <= 'F')
  92                 ch = (cp[1] - 'A' + 10) << 4;
  93             else
  94                 return (0);
  95             if (ISDIGIT(cp[2]))
  96                 ch |= (cp[2] - '0');
  97             else if (cp[2] >= 'a' && cp[2] <= 'f')
  98                 ch |= (cp[2] - 'a' + 10);
  99             else if (cp[2] >= 'A' && cp[2] <= 'F')
 100                 ch |= (cp[2] - 'A' + 10);
 101             else
 102                 return (0);
 103             cp += 2;
 104         }
 105         VSTRING_ADDCH(raw, ch);
 106     }
 107     VSTRING_TERMINATE(raw);
 108     return (raw);
 109 }
 110
 111 #ifdef TEST
 112
 113  /*
 114   * Proof-of-concept test program: convert to hex and back.
 115   */
 116 #include <vstream.h>
 117
 118 #define BUFLEN 1024
 119
 120 static ssize_t read_buf(VSTREAM *fp, VSTRING *buf)
 121 {
 122     ssize_t len;
 123
 124     VSTRING_RESET(buf);
 125     len = vstream_fread(fp, STR(buf), vstring_avail(buf));
 126     VSTRING_AT_OFFSET(buf, len);                /* XXX */
 127     VSTRING_TERMINATE(buf);
 128     return (len);
 129 }
 130
 131 int     main(int unused_argc, char **unused_argv)
 132 {
 133     VSTRING *raw = vstring_alloc(BUFLEN);
 134     VSTRING *hex = vstring_alloc(100);
 135     ssize_t len;
 136
 137     while ((len = read_buf(VSTREAM_IN, raw)) > 0) {
 138         hex_quote(hex, STR(raw));
 139         if (hex_unquote(raw, STR(hex)) == 0)
 140             msg_fatal("bad input: %.100s", STR(hex));
 141         if (LEN(raw) != len)
 142             msg_fatal("len %ld != raw len %ld", (long) len, (long) LEN(raw));
 143         if (vstream_fwrite(VSTREAM_OUT, STR(raw), LEN(raw)) != LEN(raw))
 144             msg_fatal("write error: %m");
 145     }
 146     vstream_fflush(VSTREAM_OUT);
 147     vstring_free(raw);
 148     vstring_free(hex);
 149     return (0);
 150 }
 151
 152 #endif