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

   1 /*      $NetBSD$        */
   2
   3 /*++
   4 /* NAME
   5 /*      unescape 3
   6 /* SUMMARY
   7 /*      translate C-like escape sequences
   8 /* SYNOPSIS
   9 /*      #include <stringops.h>
  10 /*
  11 /*      VSTRING *unescape(result, input)
  12 /*      VSTRING *result;
  13 /*      const char *input;
  14 /*
  15 /*      VSTRING *escape(result, input, len)
  16 /*      VSTRING *result;
  17 /*      const char *input;
  18 /*      ssize_t len;
  19 /* DESCRIPTION
  20 /*      unescape() translates C-like escape sequences in the null-terminated
  21 /*      string \fIinput\fR and places the result in \fIresult\fR. The result
  22 /*      is null-terminated, and is the function result value.
  23 /*
  24 /*      escape() does the reverse transformation.
  25 /*
  26 /*      Escape sequences and their translations:
  27 /* .IP \ea
  28 /*      Bell character.
  29 /* .IP \eb
  30 /*      Backspace character.
  31 /* .IP \ef
  32 /*      formfeed character.
  33 /* .IP \en
  34 /*      newline character
  35 /* .IP \er
  36 /*      Carriage-return character.
  37 /* .IP \et
  38 /*      Horizontal tab character.
  39 /* .IP \ev
  40 /*      Vertical tab character.
  41 /* .IP \e\e
  42 /*      Backslash character.
  43 /* .IP \e\fInum\fR
  44 /*      8-bit character whose ASCII value is the 1..3 digit
  45 /*      octal number \fInum\fR.
  46 /* .IP \e\fIother\fR
  47 /*      The backslash character is discarded.
  48 /* LICENSE
  49 /* .ad
  50 /* .fi
  51 /*      The Secure Mailer license must be distributed with this software.
  52 /* AUTHOR(S)
  53 /*      Wietse Venema
  54 /*      IBM T.J. Watson Research
  55 /*      P.O. Box 704
  56 /*      Yorktown Heights, NY 10598, USA
  57 /*--*/
  58
  59 /* System library. */
  60
  61 #include <sys_defs.h>
  62 #include <ctype.h>
  63
  64 /* Utility library. */
  65
  66 #include <vstring.h>
  67 #include <stringops.h>
  68
  69 /* unescape - process escape sequences */
  70
  71 VSTRING *unescape(VSTRING *result, const char *data)
  72 {
  73     int     ch;
  74     int     oval;
  75     int     i;
  76
  77 #define UCHAR(cp)       ((unsigned char *) (cp))
  78 #define ISOCTAL(ch)     (ISDIGIT(ch) && (ch) != '8' && (ch) != '9')
  79
  80     VSTRING_RESET(result);
  81
  82     while ((ch = *UCHAR(data++)) != 0) {
  83         if (ch == '\\') {
  84             if ((ch = *UCHAR(data++)) == 0)
  85                 break;
  86             switch (ch) {
  87             case 'a':                           /* \a -> audible bell */
  88                 ch = '\a';
  89                 break;
  90             case 'b':                           /* \b -> backspace */
  91                 ch = '\b';
  92                 break;
  93             case 'f':                           /* \f -> formfeed */
  94                 ch = '\f';
  95                 break;
  96             case 'n':                           /* \n -> newline */
  97                 ch = '\n';
  98                 break;
  99             case 'r':                           /* \r -> carriagereturn */
 100                 ch = '\r';
 101                 break;
 102             case 't':                           /* \t -> horizontal tab */
 103                 ch = '\t';
 104                 break;
 105             case 'v':                           /* \v -> vertical tab */
 106                 ch = '\v';
 107                 break;
 108             case '0':                           /* \nnn -> ASCII value */
 109             case '1':
 110             case '2':
 111             case '3':
 112             case '4':
 113             case '5':
 114             case '6':
 115             case '7':
 116                 for (oval = ch - '0', i = 0;
 117                      i < 2 && (ch = *UCHAR(data)) != 0 && ISOCTAL(ch);
 118                      i++, data++) {
 119                     oval = (oval << 3) | (ch - '0');
 120                 }
 121                 ch = oval;
 122                 break;
 123             default:                            /* \any -> any */
 124                 break;
 125             }
 126         }
 127         VSTRING_ADDCH(result, ch);
 128     }
 129     VSTRING_TERMINATE(result);
 130     return (result);
 131 }
 132
 133 /* escape - reverse transformation */
 134
 135 VSTRING *escape(VSTRING *result, const char *data, ssize_t len)
 136 {
 137     int     ch;
 138
 139     VSTRING_RESET(result);
 140     while (len-- > 0) {
 141         ch = *UCHAR(data++);
 142         if (ISASCII(ch)) {
 143             if (ISPRINT(ch)) {
 144                 if (ch == '\\')
 145                     VSTRING_ADDCH(result, ch);
 146                 VSTRING_ADDCH(result, ch);
 147                 continue;
 148             } else if (ch == '\a') {            /* \a -> audible bell */
 149                 vstring_strcat(result, "\\a");
 150                 continue;
 151             } else if (ch == '\b') {            /* \b -> backspace */
 152                 vstring_strcat(result, "\\b");
 153                 continue;
 154             } else if (ch == '\f') {            /* \f -> formfeed */
 155                 vstring_strcat(result, "\\f");
 156                 continue;
 157             } else if (ch == '\n') {            /* \n -> newline */
 158                 vstring_strcat(result, "\\n");
 159                 continue;
 160             } else if (ch == '\r') {            /* \r -> carriagereturn */
 161                 vstring_strcat(result, "\\r");
 162                 continue;
 163             } else if (ch == '\t') {            /* \t -> horizontal tab */
 164                 vstring_strcat(result, "\\t");
 165                 continue;
 166             } else if (ch == '\v') {            /* \v -> vertical tab */
 167                 vstring_strcat(result, "\\v");
 168                 continue;
 169             }
 170         }
 171         if (ISDIGIT(*UCHAR(data)))
 172             vstring_sprintf_append(result, "\\%03d", ch);
 173         else
 174             vstring_sprintf_append(result, "\\%d", ch);
 175     }
 176     VSTRING_TERMINATE(result);
 177     return (result);
 178 }
 179
 180 #ifdef TEST
 181
 182 #include <stdlib.h>
 183 #include <string.h>
 184 #include <msg.h>
 185 #include <vstring_vstream.h>
 186
 187 int     main(int argc, char **argv)
 188 {
 189     VSTRING *in = vstring_alloc(10);
 190     VSTRING *out = vstring_alloc(10);
 191     int     un_escape = 1;
 192
 193     if (argc > 2 || (argc > 1 && (un_escape = strcmp(argv[1], "-e"))) != 0)
 194         msg_fatal("usage: %s [-e (escape)]", argv[0]);
 195
 196     if (un_escape) {
 197         while (vstring_fgets_nonl(in, VSTREAM_IN)) {
 198             unescape(out, vstring_str(in));
 199             vstream_fwrite(VSTREAM_OUT, vstring_str(out), VSTRING_LEN(out));
 200         }
 201     } else {
 202         while (vstring_fgets(in, VSTREAM_IN)) {
 203             escape(out, vstring_str(in), VSTRING_LEN(in));
 204             vstream_fwrite(VSTREAM_OUT, vstring_str(out), VSTRING_LEN(out));
 205         }
 206     }
 207     vstream_fflush(VSTREAM_OUT);
 208     exit(0);
 209 }
 210
 211 #endif