ios 如何获取手机可用空间和总的存储空间的大小

#include <sys/param.h>#include <sys/mount.h>- (void)getDivceSize{    //可用大小    struct statfs buf;    long long freespace = -1;    if(statfs("/var", &buf) >= 0){        freespace = (long long)(buf.f_bsize * buf.f_bfree);    }    //总大小    struct statfs buf1;    long long maxspace = 0;    if (statfs("/", &buf1) >= 0) {        maxspace = (long long)buf1.f_bsize * buf1.f_blocks;    }    if (statfs("/private/var", &buf1) >= 0) {        maxspace += (long long)buf1.f_bsize * buf1.f_blocks;    }    NSString * sizeStr = [NSString stringWithFormat:@"可用空间%0.2fG / 总空间%0.2fG",(double)freespace/1024/1024/1024,(double)maxspace/1024/1024/1024];    self.sizeLabel.text = sizeStr;    }