You could try the Cap'n Proto bindings https://github.com/dwrensha/capnproto-rust, which supports this zero-copy pattern, and should be fast enough to saturate most disks.
On Wed, Dec 10, 2014 at 10:13 AM, Daniel Micay <danielmi...@gmail.com> wrote: > On 10/12/14 01:08 PM, Matt wrote: > > Sorry if this has been covered before, and also that I'm a complete > noob, but I'm thinking about trying a first project in Rust, and trying to > learn enough to get started. > > > > My plan is for an on-disk key-value store. I'm going to end up writing > arrays of numbers to disk, and then needing to efficiently read them out of > a mmap-ed file. So I'm wondering how in Rust you efficiently/zero-copy-ly > take some slice of a read-only mmap and treat it as e.g. a vector of ints? > > > > I see Vec.from_raw_parts() and Vec.from_raw_buf(), but I don't really > understand the difference between them, and also they seem like they just > give you a vector of the pointer's type, so I don't know how you use them > convert the u8s you get from MemoryMap.data() into a vector of a different > type, e.g. 32 bit ints. > > > > It seems like there should be a higher level API for this kind of thing, > where "casting" a slice of a read-only memory buffer into an immutable > vector is not an unsafe operation (I mean, you can do that in Python ;) > Either I don't see it in the docs, or it doesn't exist yet; just wondering > which :) > > > > Thanks! > > > > Matt > > Keep in mind that the file won't be portable if you do this. It's why > it's not a common pattern. > > > _______________________________________________ > Rust-dev mailing list > Rust-dev@mozilla.org > https://mail.mozilla.org/listinfo/rust-dev > >
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