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答复: Re: [ECOS] A question about function readdir and stat
- From: eCos at sunnorth dot com dot cn
- To: ecos-discuss at ecos dot sourceware dot org
- Cc: eCos at sunnorth dot com dot cn
- Date: Mon, 31 Mar 2008 10:35:00 +0800
- Subject: [ECOS] 答复: Re: [ECOS] A question about function readdir and stat
- Sensitivity:
Thanks very much for your answer.
We can't use the first method, though it is a very good idea. The reason
is that our application is DPF(Digital Photo Frame), a directory structure
fixed is almost impossible. Users copy and delete photo(jpeg/bmp and so
on) files to a DPF device by their own, so actually we can't control what
the users do and the directory structure is not controllable at all.
> Why not impose a directory structure. eg my camera has a directory for
> every 100 images. That would mean you only need a maximum of 100
> comparisons for the last file in the directory and for 10000 files you
> need 100 directories.
> Another option which would give a speed up is not to use numbers, but
> a more dense naming scheme. eg fAA, fAB, fAC, ..., fAZ, fAa, ... fAz,
> You still end up doing 10000 comparisons, but the strings you are
> comparing are shorted so there is less work to do.
> I assume you are using fatfs? Looking at fatfs_fo_dirread, this would
> be easy to implement. You have the information you need in dentry. So
> just add the new member d_type and fill it in.
> Andrew
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