Add try_push_uninit and test #278
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bluss
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Oct 16, 2024
| /// | ||
| /// This is useful if the backed value is large and won't fit on stack. | ||
| /// | ||
| /// Capacity error carries the data - since we don't have data then we need a different error type. |
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Something like this is needed, but unsure about the right API |
bluss
reviewed
Oct 16, 2024
| /// This is useful if the backed value is large and won't fit on stack. | ||
| /// | ||
| /// Capacity error carries the data - since we don't have data then we need a different error type. | ||
| pub unsafe fn try_push_uninit(&mut self) -> Result<*mut T, ()> { |
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Let's use a NonNull<T> for the pointer. While we think of the best shape of API for this.
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bluss
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Oct 16, 2024
| let field_two = unsafe {&mut (*ptr).field_two}; | ||
| *field_two = [2; 1_000_000]; | ||
| let field_three = unsafe {&mut (*ptr).field_three}; | ||
| *field_three = [3; 1_000_000]; |
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Raw pointer is not a good interface because the user needs to remember to use field_three.write(...). Assigning with *field_three = ... only works for Copy types. The point is that the assignment first drops the existing value before copying (nominally) the new value into its place. MaybeUninit is a good place to look.
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Perhaps this could take the same shape as |
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@tbu- that sounds good! |
tbu-
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This mirrors `Vec::spare_capacity_mut`. Description and example are taken from this function, too. CC bluss#278
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This mirrors `Vec::spare_capacity_mut`. Description and example are taken from this function, too. CC bluss#278
tbu-
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This mirrors `Vec::spare_capacity_mut`. Description and example are taken from this function, too. CC bluss#278
bluss
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This mirrors `Vec::spare_capacity_mut`. Description and example are taken from this function, too. CC #278
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Add try_push_uninit , which tries to add an additional element and provides a raw pointer to the already allocated memory.
This is useful if the backing structure is larger than the stack size.
Included is a test that demonstrates the need for this functionality.