oc语言复制视频文件

void copyFile()
{
    NSString *home=NSHomeDirectory();
    NSString *path=[NSString stringWithFormat:@"%@/desktop/oc.mp4",home];
    NSString *path1=[NSString stringWithFormat:@"%@/desktop/oc1.mp4",home];
    NSFileHandle *handle=[NSFileHandle fileHandleForReadingAtPath:path];
    NSFileManager *fm=[NSFileManager defaultManager];
    BOOL ret=NO;
    if ([fm fileExistsAtPath:path1])
    {
        NSLog(@"存在");
    }
    else
    {
       ret= [fm createFileAtPath:path1 contents:nil attributes:nil];
    
    }
    NSFileHandle *writeHandle=[NSFileHandle fileHandleForWritingAtPath:path1];
    NSData *data=nil;
    if (ret==YES)
    {
        data=[handle readDataOfLength:1024*1024];
        while ([data length]==1024*1024)
        {
            [writeHandle writeData:data];
            data=[handle readDataOfLength:1024*1024];
        }
        [writeHandle writeData:data];
    }
    [handle closeFile];
    [writeHandle closeFile];

}