C — Directory exploration - c

Question

I want to dynamically populate an array of strings with file name and directory name that are inside the specified directory path.
According to you, is this the fastest implementation for this purpose?
If not, can you suggest an alternative implementation?
int exploreDirectory(const char *dirpath, char ***list, int *numItems) {
DIR *dirstream = NULL;
struct dirent *direntp = NULL;
size_t listSize = 5;
errno = 0;
if (!(dirstream = opendir(dirpath)))
return errno;
if (!((*list) = malloc(sizeof(char *) * listSize))) {
fprintf(stderr, "Error in list allocation for file list: dirpath=%s.\n", dirpath);
exit(EXIT_FAILURE);
}
*numItems = 0;
while(1) {
errno = 0;
if (!(direntp = readdir(dirstream)))
break;
if (*numItems + 1 == listSize) {
listSize *= 2;
if (!((*list) = realloc((*list), sizeof(char *) * listSize))) {
fprintf(stderr, "Error in list reallocation for file list: dirpath=%s.\n", dirpath);
exit(EXIT_FAILURE);
}
}
*numItems += 1;
(*list)[*numItems - 1] = stringDuplication(direntp->d_name);
}
if (errno != 0) {
fprintf(stderr, "Error in readdir for file list: dirpath=%s.\n", dirpath);
exit(EXIT_FAILURE);
}
if (closedir(dirstream) == -1) {
fprintf(stderr, "Error in closedir for file list: dirpath=%s.\n", dirpath);
exit(EXIT_FAILURE);
}
free(direntp);
return 0;
}

Answer 1

This is the implementation based on scandir!
int exploreDirectory(const char *dirpath, char ***list, int *numItems) {
struct dirent **direntList;
int i;
errno = 0;
if ((*numItems = scandir(dirpath, &direntList, NULL, alphasort)) == -1)
return errno;
if (!((*list) = malloc(sizeof(char *) * (*numItems)))) {
fprintf(stderr, "Error in list allocation for file list: dirpath=%s.\n", dirpath);
exit(EXIT_FAILURE);
}
for (i = 0; i < *numItems; i++) {
(*list)[i] = stringDuplication(direntList[i]->d_name);
}
for (i = 0; i < *numItems; i++) {
free(direntList[i]);
}
free(direntList);
return 0;
}