2 unstable releases
new 0.1.0  May 14, 2024 

0.0.1  Apr 25, 2024 
#290 in Data structures
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heapsz
A crate for calculating the heap usage of a data structure.
It's simple. Only one required method in the HeapSize
trait, which can be
generated by #[derive(HeapSize)]
.
It's fast. It estimates an approximate heap size in O(1) time.
Usage
Examples
Calculate heap_size()
selectively
Example  Expanded example 



Calculate heap_size()
of all fields
Example  Expanded example 



Skip irrelative fields
Example  Expanded example 



Implement HeapSize for thirdparty structs
Example  Expanded example 



#[derive(HeapSize)]
Field attributes
Apply to one field in a struct or in an enum variant.

#[heap_size]
By default,
#[derive(HeapSize)]
generates an empty implementation which always return 0.#[heap_size]
needs to be added to fields that have a heap allocation.This is because of 1) most struct does not contain heap allocation at all, and 2) they often do not implement the
HeapSize
trait. 
#[heap_size(skip)]
Skip this field: do not calculate its heap size.
Requires a struct has a container attribute
#[heap_size]
. 
#[heap_size(with = "module")]
#[derive(HeapSize)]
will use$module::heap_size
as the function to obtain this field’s heap size.
Container attributes
Apply to a struct or enum declaration.
#[heap_size]
By default,#[derive(HeapSize)]
generates an empty implementation that always return 0. By adding#[heap_size]
, it sums upheap_size()
of all fields in a struct or an enum.
Variant attributes
Apply to a variant of an enum.

#[heap_size]
Generate By default,
#[derive(HeapSize)]
generates an empty implementation which always return 0. By adding#[heap_size]
, it sums upheap_size()
of fields in a variant. 
#[heap_size(skip)]
Skip this variant: do not calculate its heap size.
Requires an enum has a
#[heap_size]
container attribute.
License
This project is licensed under the MIT license.
Dependencies
~0–370KB