string parsing with strtok_r

Question

my string looks like this:

abcd "efgh [data\]" pqrl 12fgd]

I want to parse till ']' which is not proceeded by a backslash '\\'

Can I do it with strtok_r ? If not than how should I do it?

Answer 1

You could do it with strchr . Here is how I would try to do it (untested):

p = str;
while ((p = strchr(p, ']')) {
    if (p > str && *(p-1) != '\')
        /* This is it. */

Answer 2

There is no one shot method to doing this using strtok_r . Since your delimiter is a single character you can always reconstruct the string you want by stuffing back the delimiter if the last character of a token returned by strtok_r is '\\'.

#include <stdio.h>
#include <string.h>

int main()
{
  char str[] = "abcd \"efgh [data\\]\" pqrl 12fgd]";
  char *tokens[2] = {0};
  char *pToken = str;
  unsigned int i = 0;

  for( tokens[i] = strtok_r( str, "]", &pToken ); ++i < 2; 
    tokens[i] = strtok_r( NULL, "]", &pToken ) ) {
  }

  for( i = 0; i < 2; ++i ) {
    printf( "token %d = %s\n", i, tokens[i] );
  }

  for( i = 0; i < 2; ++i ) {
    if( tokens[i][strlen(tokens[i]) - 1] == '\\' ) {
      tokens[i][strlen(tokens[i])] = ']';
    }
  }

  printf( "output = %s\n", str );

  return 0;
}

This outputs:

token 0 = abcd "efgh [data\
token 1 = " pqrl 12fgd
output = abcd "efgh [data\]" pqrl 12fgd

Answer 3

strtok searches for any single character in the set to be searched for. You could split on ] and then check which ones had a preceding \\ but you can't search for a regex with it.