calculating directory size in cocoa - xcode

Question

I want to calculate the directory (folder)size and i have to list all files and folders (subfolders) in a volume(drive) with its corresponding size.I am using the below code to calculate size.The problem with this code is the performance issue . I am using NSBrowser to display .
NSArray *filesArray = [[NSFileManager defaultManager] subpathsOfDirectoryAtPath:folderPath error:nil];
NSEnumerator *filesEnumerator = [filesArray objectEnumerator];
NSString *fileName;
unsigned long long int fileSize = 0;
while (fileName = [filesEnumerator nextObject])
{
NSDictionary *fileDictionary = [[NSFileManager defaultManager] attributesOfItemAtPath:folderPath error:nil];
fileSize += [fileDictionary fileSize];
}
return fileSize;
Questions:
Is there any built in function available?
If not what is the best way to calculate the size?
Is it good to use cache to store already calculated file size?
Thanks...

Answer 1

You can use stat.
-(unsigned long long)getFolderSize : (NSString *)folderPath;
{
char *dir = (char *)[folderPath fileSystemRepresentation];
DIR *cd;
struct dirent *dirinfo;
int lastchar;
struct stat linfo;
static unsigned long long totalSize = 0;
cd = opendir(dir);
if (!cd) {
return 0;
}
while ((dirinfo = readdir(cd)) != NULL) {
if (strcmp(dirinfo->d_name, ".") && strcmp(dirinfo->d_name, "..")) {
char *d_name;
d_name = (char*)malloc(strlen(dir)+strlen(dirinfo->d_name)+2);
if (!d_name) {
//out of memory
closedir(cd);
exit(1);
}
strcpy(d_name, dir);
lastchar = strlen(dir) - 1;
if (lastchar >= 0 && dir[lastchar] != '/')
strcat(d_name, "/");
strcat(d_name, dirinfo->d_name);
if (lstat(d_name, &linfo) == -1) {
free(d_name);
continue;
}
if (S_ISDIR(linfo.st_mode)) {
if (!S_ISLNK(linfo.st_mode))
[self getFolderSize:[NSString stringWithCString:d_name encoding:NSUTF8StringEncoding]];
free(d_name);
} else {
if (S_ISREG(linfo.st_mode)) {
totalSize+=linfo.st_size;
} else {
free(d_name);
}
}
}
}
closedir(cd);
return totalSize;
}
Take a look at Mac OS X not reporting directory sizes correctly?

Answer 2

1. Is there any built in function available?
fileSize is a built-in function that gives you size.
2. If not what is the best way to calculate the size?
This method is good enough to calculate size of a folder/directory.
3. Is it good to use cache to store already calculated file size?
Yes you can store it in cache.