malloc() for an array of strings, not working as hoping - c

Question

I am trying to make a function that takes a string and a pointer to an array of strings and malloc() the array of char arrays and copies each individual word of the string. This is what I have so far, I think I'm close, I'm just struggling with using malloc() on an array of arrays.
int string_parser(char *inp, char **array_of_words_p[])
{
int CurrentChar = 0; //Variable Initialization
char *buffer; //Variable Initialization
/* Allocate memory and check for errors allocating memory */
//Allocate memory to buffer the size of the input string
buffer = (char*)malloc(strlen(inp));
if (buffer == NULL)
{
printf("Error allocating memory..\n");
return -1;
}
/* Move input string into buffer before processing */
for (CurrentChar = 0; CurrentChar < strlen(inp) + 1; CurrentChar++)
{ //For every character in input
if (inp != NULL)
{
//Move input character into buffer
buffer[CurrentChar] = inp[CurrentChar];
}
}
/* Convert string into array of words */
char ** stringbuffer = NULL;
//Convert string to array of words
char * CurrentWord = strtok_s(buffer, " ", *array_of_words_p);
//Variable Initialization
int numspaces = 0;
while (CurrentWord)
{
//Allocate memory for size of string
stringbuffer = (char**)realloc(stringbuffer, sizeof(char**) * ++numspaces);
if (stringbuffer == NULL)
{
return -1;
}
stringbuffer[numspaces - 1] = CurrentWord;
//Reset Current word to null
CurrentWord = strtok_s(NULL, " ", *array_of_words_p);
}
//Reallocate memory to include terminating character
stringbuffer = (char**)realloc(stringbuffer, sizeof(char**) * (numspaces + 1));
stringbuffer[numspaces] = 0;
/* Write processed data into returned argument */
*array_of_words_p = (char**)malloc(sizeof(char**) * (numspaces + 2));
memcpy(*array_of_words_p, stringbuffer, (sizeof(char*) * (numspaces + 2)));
free(stringbuffer);
return numspaces;
}

Answer 1

//Allocate memory to buffer the size of the input string
buffer = (char*)malloc(strlen(inp));
The size of the input string includes the terminating \0, so you need:
buffer = malloc(strlen(inp)+1);
//Convert string to array of words
char * CurrentWord = strtok_s(buffer, " ", *array_of_words_p);
It's unwise to abuse the *array_of_words_p for the context save variable, as this requires it to be initialized appropriately. Better:
char *context, *CurrentWord = strtok_s(buffer, " ", &context);
…
CurrentWord = strtok_s(NULL, " ", &context);
//Allocate memory for size of string
stringbuffer = (char**)realloc(stringbuffer, sizeof(char**) * ++numspaces);
It likely doesn't hurt (owing to equal pointer sizes), but sizeof(char**) is strictly speaking wrong, since the elements of the array of strings are of type char *. Correct:
stringbuffer = realloc(stringbuffer, sizeof (char *) * ++numspaces);
…
stringbuffer = realloc(stringbuffer, sizeof (char *) * (numspaces + 1));
/* Write processed data into returned argument */
*array_of_words_p = (char**)malloc(sizeof(char**) * (numspaces + 2));
memcpy(*array_of_words_p, stringbuffer, (sizeof(char*) * (numspaces + 2)));
free(stringbuffer);
You can spare this unnecessary copying and by the way avoid accessing the unallocated memory stringbuffer[numspaces+1] by replacing the above with just:
*array_of_words_p = stringbuffer;
Apart from that all, your function works and can be called like:
char **array_of_words;
int n = string_parser("this here is an example string", &array_of_words);
for (int i = 0; i < n; ++i) puts(array_of_words[i]);