获取文件夹大小

IOS里面没有获取整个目录里面所有文件大小的函数，所以只能遍历然后累加。

//获取文件大小 
+(long long)getFileSize:(NSString*)filePath

{
    return [self _folderSizeAtPath:[filePath cStringUsingEncoding:NSUTF8StringEncoding]];
}

+ (long long) _folderSizeAtPath: (const char*)folderPath

{
long long folderSize = 0;
DIR* dir = opendir(folderPath);
if (dir == NULL) return 0;
struct dirent* child;
while ((child = readdir(dir))!=NULL)

{
if (child->d_type DT_DIR &&，，，，，，，，，，，，，，，，，，，，，， (
(child->d_name[0] '.' && child->d_name¹ 0) || // 忽略目录 .
(child->d_name[0] '.' && child->d_name¹ '.' && child->d_name[2] 0) // 忽略目录 ..
)) continue;

int folderPathLength = strlen(folderPath);
       char childPath[1024]; // 子文件的路径地址
       stpcpy(childPath, folderPath);
       if (folderPath[folderPathLength-1] != '/'){
           childPath[folderPathLength] = '/';
           folderPathLength++;
       }
       stpcpy(childPath+folderPathLength, child->d_name);
       childPath[folderPathLength + child->d_namlen] = 0;
       if (child->d_type == DT_DIR){ // directory
           folderSize += [self _folderSizeAtPath:childPath]; // 递归调用子目录
           // 把目录本身所占的空间也加上
           struct stat st;
           if(lstat(childPath, &st) == 0) folderSize += st.st_size;
       }else if (child->d_type  DT_REG || child->d_type  DT_LNK){ // file or link
           struct stat st;
           if(lstat(childPath, &st) == 0) folderSize += st.st_size;
       }
   }
   return folderSize;
}