Mrthdrb

I'm new to C language and want to explode a string like we do in PHP explode() function, I searched for a built-in function with the C standard library, and I found strtok , but It doesn't support empty tokens like 1,2,3,,5 . Inspired by the answers I found in this SO question I made this function, it is supposed to be thread safe and support empty tokens and doesn't change the original string

char* strTok(char** newString, char* delimiter)

 char* string = *newString;
 char* delimiterFound = (char*) 0;
 int tokLenght = 0;
 char* tok = (char*) 0;

 if(!string) return (char*) 0;

 delimiterFound = strstr(string, delimiter);

 if(delimiterFound)
 tokLenght = delimiterFound-string;
 else
 tokLenght = strlen(string);
 

 tok = malloc(tokLenght + 1);
 memcpy(tok, string, tokLenght);
 tok[tokLenght] = '';

 *newString = delimiterFound ? delimiterFound + strlen(delimiter) : (char*)0;

 return tok;

I designed it to be used like

char* input = "1,2,3,4,5,6,7,,,10,";
char** inputP = &input;
char* tok;
while( (tok=strTok(inputP, ",")) )
 printf("%sn", tok);

• delimiterFound + strlen(delimiter) sounds like a bug. If the delimiter is longer than one character, *newString will point too far into the original, maybe even beyond the end. Correct me if I am wrong, delimiterFound + 1 is what you are actually after.



• 
  

  Modern C allows, and strongly encourages, to declare variables as close to their use a possible. Consider

  
  
  

  char * delimiterFound = strstr(string, delimiter);
  ....
  char * tok = malloc(tokLenght + 1);
  

  
  
  

  etc.

  
  



• Always test that malloc didn't fail.



• 
  

  More spaces - around keywords, braces, etc - definitely improve readability:

  
  
  

   if (....) 
   ....
   else 
   ....
   
  

  
  

From a readability viewpoint, you should use NULL instead of (char*) 0 as it is easier to recognize what you're trying to do. Also, the tokLenght misspells "length", and should probably be tokLength.

You leak memory, as the memory allocated to hold the returned string is never freed.