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

   1 /*      $NetBSD$        */
   2
   3 /*++
   4 /* NAME
   5 /*      hex_code 3
   6 /* SUMMARY
   7 /*      encode/decode data, hexadecimal style
   8 /* SYNOPSIS
   9 /*      #include <hex_code.h>
  10 /*
  11 /*      VSTRING *hex_encode(result, in, len)
  12 /*      VSTRING *result;
  13 /*      const char *in;
  14 /*      ssize_t len;
  15 /*
  16 /*      VSTRING *hex_decode(result, in, len)
  17 /*      VSTRING *result;
  18 /*      const char *in;
  19 /*      ssize_t len;
  20 /* DESCRIPTION
  21 /*      hex_encode() takes a block of len bytes and encodes it as one
  22 /*      upper-case null-terminated string.  The result value is
  23 /*      the result argument.
  24 /*
  25 /*      hex_decode() performs the opposite transformation on
  26 /*      lower-case, upper-case or mixed-case input. The result
  27 /*      value is the result argument. The result is null terminated,
  28 /*      whether or not that makes sense.
  29 /* DIAGNOSTICS
  30 /*      hex_decode() returns a null pointer when the input contains
  31 /*      characters not in the hexadecimal alphabet.
  32 /* LICENSE
  33 /* .ad
  34 /* .fi
  35 /*      The Secure Mailer license must be distributed with this software.
  36 /* AUTHOR(S)
  37 /*      Wietse Venema
  38 /*      IBM T.J. Watson Research
  39 /*      P.O. Box 704
  40 /*      Yorktown Heights, NY 10598, USA
  41 /*--*/
  42
  43 /* System library. */
  44
  45 #include <sys_defs.h>
  46 #include <ctype.h>
  47 #include <string.h>
  48
  49 /* Utility library. */
  50
  51 #include <msg.h>
  52 #include <mymalloc.h>
  53 #include <vstring.h>
  54 #include <hex_code.h>
  55
  56 /* Application-specific. */
  57
  58 static const unsigned char hex_chars[] = "0123456789ABCDEF";
  59
  60 #define UCHAR_PTR(x) ((const unsigned char *)(x))
  61
  62 /* hex_encode - raw data to encoded */
  63
  64 VSTRING *hex_encode(VSTRING *result, const char *in, ssize_t len)
  65 {
  66     const unsigned char *cp;
  67     int     ch;
  68     ssize_t count;
  69
  70     VSTRING_RESET(result);
  71     for (cp = UCHAR_PTR(in), count = len; count > 0; count--, cp++) {
  72         ch = *cp;
  73         VSTRING_ADDCH(result, hex_chars[(ch >> 4) & 0xf]);
  74         VSTRING_ADDCH(result, hex_chars[ch & 0xf]);
  75     }
  76     VSTRING_TERMINATE(result);
  77     return (result);
  78 }
  79
  80 /* hex_decode - encoded data to raw */
  81
  82 VSTRING *hex_decode(VSTRING *result, const char *in, ssize_t len)
  83 {
  84     const unsigned char *cp;
  85     ssize_t count;
  86     unsigned int hex;
  87     unsigned int bin;
  88
  89     VSTRING_RESET(result);
  90     for (cp = UCHAR_PTR(in), count = len; count > 0; cp += 2, count -= 2) {
  91         if (count < 2)
  92             return (0);
  93         hex = cp[0];
  94         if (hex >= '0' && hex <= '9')
  95             bin = (hex - '0') << 4;
  96         else if (hex >= 'A' && hex <= 'F')
  97             bin = (hex - 'A' + 10) << 4;
  98         else if (hex >= 'a' && hex <= 'f')
  99             bin = (hex - 'a' + 10) << 4;
 100         else
 101             return (0);
 102         hex = cp[1];
 103         if (hex >= '0' && hex <= '9')
 104             bin |= (hex - '0');
 105         else if (hex >= 'A' && hex <= 'F')
 106             bin |= (hex - 'A' + 10);
 107         else if (hex >= 'a' && hex <= 'f')
 108             bin |= (hex - 'a' + 10);
 109         else
 110             return (0);
 111         VSTRING_ADDCH(result, bin);
 112     }
 113     VSTRING_TERMINATE(result);
 114     return (result);
 115 }
 116
 117 #ifdef TEST
 118
 119  /*
 120   * Proof-of-concept test program: convert to hexadecimal and back.
 121   */
 122
 123 #define STR(x)  vstring_str(x)
 124 #define LEN(x)  VSTRING_LEN(x)
 125
 126 int     main(int unused_argc, char **unused_argv)
 127 {
 128     VSTRING *b1 = vstring_alloc(1);
 129     VSTRING *b2 = vstring_alloc(1);
 130     char   *test = "this is a test";
 131
 132 #define DECODE(b,x,l) { \
 133         if (hex_decode((b),(x),(l)) == 0) \
 134             msg_panic("bad hex: %s", (x)); \
 135     }
 136 #define VERIFY(b,t) { \
 137         if (strcmp((b), (t)) != 0) \
 138             msg_panic("bad test: %s", (b)); \
 139     }
 140
 141     hex_encode(b1, test, strlen(test));
 142     DECODE(b2, STR(b1), LEN(b1));
 143     VERIFY(STR(b2), test);
 144
 145     hex_encode(b1, test, strlen(test));
 146     hex_encode(b2, STR(b1), LEN(b1));
 147     hex_encode(b1, STR(b2), LEN(b2));
 148     DECODE(b2, STR(b1), LEN(b1));
 149     DECODE(b1, STR(b2), LEN(b2));
 150     DECODE(b2, STR(b1), LEN(b1));
 151     VERIFY(STR(b2), test);
 152
 153     hex_encode(b1, test, strlen(test));
 154     hex_encode(b2, STR(b1), LEN(b1));
 155     hex_encode(b1, STR(b2), LEN(b2));
 156     hex_encode(b2, STR(b1), LEN(b1));
 157     hex_encode(b1, STR(b2), LEN(b2));
 158     DECODE(b2, STR(b1), LEN(b1));
 159     DECODE(b1, STR(b2), LEN(b2));
 160     DECODE(b2, STR(b1), LEN(b1));
 161     DECODE(b1, STR(b2), LEN(b2));
 162     DECODE(b2, STR(b1), LEN(b1));
 163     VERIFY(STR(b2), test);
 164
 165     vstring_free(b1);
 166     vstring_free(b2);
 167     return (0);
 168 }
 169
 170 #endif