mmaped into vec | Rust Programming Language Community | Page 1

naive granite Aug 23, 2022, 10:10 PM

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creating a vec from that is extremely unwise

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any reason you're not using a crate for that?

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i'm not all that familiar with mmapping, but what's your reason for using vec?

thick cove Aug 23, 2022, 10:13 PM

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Vec::leak ?

naive granite Aug 23, 2022, 10:14 PM

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creating a slice would be a lot safer, and many of vec's methods are actually on slice

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note that using Vec::leak for this is just a roundabout way of using slice::from_raw_parts_mut

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That doesn't sound right

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slice::from_raw_parts(mmaped, 16) should create a valid slice (of course you'll still need to bound the lifetime appropriately)

thick cove Aug 23, 2022, 10:16 PM

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I think what you want here is to create a slice of &mut [MaybeUninit<u8>]

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Probably should also read the code of a crate that does it like
https://docs.rs/memmap2/latest/memmap2/struct.Mmap.html

Mmap in memmap2 - Rust

A handle to an immutable memory mapped buffer.

naive granite Aug 23, 2022, 10:20 PM

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i would just avoid creating the vec in the first place. It's a bad idea

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if you also want to be able to push to the unitialized part of the mmap, you really want to create a wrapper struct around it. And destroy the mmap in its Drop impl etc, etc. I havent looked at the memmap2 crate but i imagine it does something like that

#mmaped into vec