1 #include <stdio.h>

     2 

     3 #include "sreplace.h"

     4 

     5 /* Complete set of backslash sequences:

     6 

     7  From K&R, The C Programming Language, Chapter 2, Constants.

     8 

     9  \b backspace

    10  \?  question mark

    11  \f formfeed

    12   \' single quote

    13  \n newline

    14  \" double quote

    15  \r carriage return

    16  \ooo octal number

    17  \t horizontal tab

    18  \xhh hexadecimal number 

    19  \v vertical tab

    20 

    21  (\\ backslash)

    22 */

    23 

    24 /* Returns length */

    25 int parse_backslashes(unsigned char *str)

    26 {

    27   int was_backslash = 0;

    28   int was_octal = 0; /* 0 to 3 */

    29   int was_hex = 0; /* 0 to 2 */

    30   unsigned char *write_str = str;

    31   unsigned char *start = str;

    32   unsigned char newchar;

    33 

    34   while (*str != 0)

    35   {

    36     if (*str == '\\' && !was_backslash)

    37       was_backslash = 1;

    38     else

    39     {

    40       if (was_octal)

    41       {

    42         if (was_octal < 3 && *str >= '0' && *str <= '7')

    43         {

    44           newchar = (newchar * 8) + (*str - '0');

    45           was_octal += 1;

    46           if (was_octal == 3)

    47           {

    48             *(write_str++) = newchar;

    49             was_octal = 0;

    50           }

    51         } else /* Didn't come octal char. End of oct string. */

    52         {

    53           *(write_str++) = newchar;

    54           *(write_str++) = *str;

    55           was_octal = 0;

    56         }

    57       }

    58       else if (was_hex)

    59       {

    60         unsigned char base = 0;

    61 

    62         if (*str >= '0' && *str <= '9')

    63           base = '0';

    64         else if (*str >= 'a' && *str <= 'f')

    65           base = 'a' - 10;

    66         else if (*str >= 'A' && *str <= 'F')

    67           base = 'A' - 10;

    68 

    69         if (base != 0) /* Came hex char */

    70         {

    71           newchar = (newchar * 16) + (*str - base);

    72           was_hex += 1;

    73 

    74           if (was_hex == 3) /* End of hex string */

    75           {

    76             *(write_str++) = newchar;

    77             was_hex = 0;

    78           }

    79         }

    80         else /* Non-hex char came. End of hex string */

    81         {

    82           *(write_str++) = newchar;

    83           *(write_str++) = *str;

    84           was_hex = 0;

    85         }

    86       }

    87       else if (was_backslash)

    88       { switch(*str)

    89         {

    90           case '\\':

    91             *(write_str++) = '\\';

    92             break;

    93           case 'n':

    94             *(write_str++) = '\n';

    95             break;

    96           case 't':

    97             *(write_str++) = '\t';

    98             break;

    99           case 'r':

   100             *(write_str++) = '\r';

   101             break;

   102           case 'v':

   103             *(write_str++) = '\v';

   104             break;

   105           case 'f':

   106             *(write_str++) = '\f';

   107             break;

   108           case 'b':

   109             *(write_str++) = '\b';

   110             break;

   111           case '0':

   112           case '1':

   113           case '2':

   114           case '3':

   115           case '4':

   116           case '5':

   117           case '6':

   118           case '7':

   119             was_octal = 1;

   120             newchar = 0;

   121             break;

   122           case 'x':

   123             was_hex = 1;

   124             newchar = 0;

   125             break;

   126           default:

   127             *(write_str++) = *str;

   128         }

   129         was_backslash = 0;

   130       }

   131       else

   132         *(write_str++) = *str;

   133     }

   134     ++str;

   135   }

   136   *(write_str) = '\0';

   137 

   138   /* We calculate length with distance between the last

   139    * written char and the start of the string */

   140   return write_str - start;

   141 }

   142 

   143 void print_hex(FILE *out, const struct String *str)

   144 {

   145     int i;

   146 

   147     fprintf(out, "Length: %i\n", str->length);

   148     for (i = 0; i < str->length; ++i)

   149         fprintf(out, "%02hhx", str->ptr[i]);

   150 }