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Change String representation to actual (#1817)

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Tested with rust 2015, 2018, 2021 and 2024, on amd64 musl, amd64 glibc
and aarch64 musl, all of them represent Strings with (ptr, capacity,
len).

This is an internal implementation detail, that shouldn't be exposed
anyway, so it's no big deal, but in the speaker notes, we provide a
debugging tool for demonstration purposes, so at least that should have
a correct output.
This commit is contained in:
Gergely Risko 2024-02-15 23:24:19 +01:00 committed by GitHub
parent f391e863ab
commit adaa04f961
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1 changed files with 11 additions and 11 deletions
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22
src/memory-management/review.md
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@ -29,17 +29,17 @@ fn main() {
```
```bob
Stack Heap
.- - - - - - - - - - - - - -. .- - - - - - - - - - - - - - - -.
: : : :
Stack
.- - - - - - - - - - - - - -. Heap
: : .- - - - - - - - - - - - - - - -.
: s1 : : :
: +-----------+-------+ : : +----+----+----+----+----+ :
: | ptr | o---+---+-----+-->| H | e | l | l | o | :
: | len | 5 | : : +----+----+----+----+----+ :
: | capacity | 5 | : : :
: +-----------+-------+ : : :
: : `- - - - - - - - - - - - - - - -'
`- - - - - - - - - - - - - -'
: | capacity | 5 | : : +----+----+----+----+----+ :
: | ptr | o-+---+-----+-->| H | e | l | l | o | :
: | len | 5 | : : +----+----+----+----+----+ :
: +-----------+-------+ : : :
: : : :
`- - - - - - - - - - - - - -' `- - - - - - - - - - - - - - - -'
```
<details>
@ -65,8 +65,8 @@ fn main() {
// String provides no guarantees about its layout, so this could lead to
// undefined behavior.
unsafe {
let (ptr, capacity, len): (usize, usize, usize) = std::mem::transmute(s1);
println!("ptr = {ptr:#x}, len = {len}, capacity = {capacity}");
let (capacity, ptr, len): (usize, usize, usize) = std::mem::transmute(s1);
println!("capacity = {capacity}, ptr = {ptr:#x}, len = {len}");
}
}
```