strtok_r - get indicate when there is nothing between the delimiters - c

Question

i use strtok_r like:
char *the_sting = "a|b||e|f";
char *last;
char *current;
current = (char*)strtok_r(the_sting, "|", &last);
while(current != NULL)
{
printf(current);
printf("\n");
current = (char*)strtok_r(NULL, "|", &last);
}
i get:
>>a
>>b
>>e
>>f
the problem is, that i need 'blank' when there is nothing between the delimiters.
like:
>>a
>>b
>>
>>e
>>f

Answer 1

Compare the current current with the previous current. If the difference is more than strlen(previous_current) + 1 then one or more empty places was skipped.

Answer 2

Then strtok_r is not your function, furthermore, you can't use a string literal char *the_sting = "a|b||e|f"; because strtok_r modifies such string, use an array instead char the_sting[] = "a|b||e|f";
And finally, do not use printf in this way printf(current); (is dangerous), instead:
printf("%s", current);
This little function does what you want:
#include <stdio.h>
#include <string.h>
char *scan(char **pp, char c)
{
char *s, *p;
p = strchr(*pp, c);
if (p) *p++ = '\0';
s = *pp;
*pp = p;
return s;
}
int main(void)
{
char the_sting[] = "a|b||e|f"; /* I think you mean the_string here */
char *s, *p = the_sting;
while (p) {
s = scan(&p, '|');
printf("<%s>", s);
}
return 0;
}
Note that a simple char (not a string) is used as delimiter

Answer 3

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
char *my_strtok_r(char *str, const char *delims, char **store){
char *p, *wk;
if(str != NULL){
*store = str;
}
if(*store == NULL) return NULL;
//*store += strspn(*store, delims);//skip delimiter
if(**store == '\0') return NULL;
p=strpbrk(wk=*store, delims);
if(p != NULL){
*p='\0';
*store = p + 1;
} else {
*store = NULL;
}
return wk;
}
int main(void){
char the_sting[] = "a|b||e|f";
char *last;
char *current;
current = my_strtok_r(the_sting, "|", &last);
while(current != NULL)
{
printf(current);
printf("\n");
current = my_strtok_r(NULL, "|", &last);
}
return 0;
}

Answer 4

It's easy to roll your own, really:
#include <string.h>
typedef struct {
const unsigned char *data;
size_t len;
} buffer_t;
/* Use strpbrk() for multiple delimiters. */
buffer_t
memtok(const void *s, size_t length, const char *delim, buffer_t *save_ptr)
{
const unsigned char *stream,
*token;
size_t len = 0;
if (NULL == s) {
stream = save_ptr->data;
} else {
stream = s;
save_ptr->len = length;
}
token = stream;
/* Advance until either a token is found or the stream exhausted. */
while (save_ptr->len--) {
if (memchr(delim, *stream, strlen(delim))) {
/* Point save_ptr past the (non-existent) token. */
save_ptr->data = stream + 1;
return (buffer_t) { .data = token, .len = len };
}
++len;
++stream;
}
/* State : done. */
*save_ptr = (buffer_t) { .data = NULL, .len = 0 };
/* Stream exhausted but no delimiters terminate it. */
return (buffer_t){ .data = token, .len = len };
}
and for a short test:
int main(int argc, char **argv)
{
const char *the_sting = "a|b||e|f";
buffer_t kek = { .data = the_sting, .len = 8 },
token, state;
token = memtok(the_sting, 8, "|", &state);
while (token.data != NULL) {
char test[512];
memcpy(test, token.data, token.len);
test[token.len] = 0;
printf("%s\n", test);
token = memtok(NULL, 0, "|", &state);
}
return 0;
}

Answer 5

how about this:
char s[] = "1,2,,,,,,,3,4,5,6";
char *tok, *saved;
tok = strtok_r(s, ",", &saved);
do
{
fprintf(stderr, "tok = %s, saved = %s\n", tok, saved);;
if (',' == *saved)
{
while (',' == *saved++ )
{
fprintf(stderr, "saved = %s\n", saved);;
}
*saved--;
}
} while( (tok = (strtok_r(((void *)0), ",", &saved))));