Struct IndexAllocator

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pub struct IndexAllocator { /* private fields */ }

Expand description

Allocates and deallocates indices for a ExposedGenVec

Implementations§

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impl IndexAllocator

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pub fn new() -> IndexAllocator

Returns a new empty IndexAllocator

§Examples

use gen_vec::exposed::IndexAllocator;
let mut allocator: IndexAllocator = IndexAllocator::new();

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pub fn with_capacity(capacity: usize) -> IndexAllocator

Returns a IndexAllocator with initial capacity of capacity

Allows the IndexAllocator to hold capacity elements before allocating more space

§Examples

use gen_vec::exposed::IndexAllocator;
let mut allocator: IndexAllocator = IndexAllocator::with_capacity(5);

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pub fn allocate(&mut self) -> Index

Allocates and returns a new Index

Activates a freed index if there are any, otherwise creates and adds a new index to active_indices

§Examples

use gen_vec::Index;
use gen_vec::exposed::IndexAllocator;

let mut allocator: IndexAllocator = IndexAllocator::new();
let index: Index = allocator.allocate();

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pub fn deallocate(&mut self, index: Index)

Frees index if it hasn’t been already.

Afterwards, index is added to the pool of free indices available for reuse

§Examples

use gen_vec::Index;
use gen_vec::exposed::IndexAllocator;

let mut allocator: IndexAllocator = IndexAllocator::new();
let index: Index = allocator.allocate();
allocator.deallocate(index);

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pub fn deallocate_all(&mut self)

Frees all active indices and adds them to the pool of free indices

§Examples

use gen_vec::exposed::IndexAllocator;
use gen_vec::Index;

let mut allocator: IndexAllocator = IndexAllocator::new();
for _ in 0..10
{
    allocator.allocate();
}
assert_eq!(allocator.num_active(), 10);
assert_eq!(allocator.num_free(), 0);

allocator.deallocate_all();
assert_eq!(allocator.num_active(), 0);
assert_eq!(allocator.num_free(), 10);

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pub fn capacity(&self) -> usize

Reserved capacity within the IndexAllocator

§Examples

use gen_vec::exposed::IndexAllocator;

let mut allocator: IndexAllocator = IndexAllocator::with_capacity(5);
assert_eq!(allocator.capacity(), 5);

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pub fn reserve(&mut self, additional: usize)

Reserves extra space for at least additional more elements

More space may be allocated to avoid frequent re-allocations (as per the specifications of std::vec::Vec)

§Examples

use gen_vec::Index;
use gen_vec::exposed::IndexAllocator;

let mut allocator: IndexAllocator = IndexAllocator::new();
let index: Index = allocator.allocate();
allocator.reserve(4);
assert!(allocator.capacity() >= 4);

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pub fn is_active(&self, index: Index) -> bool

Returns if index is still active and hasn’t been deallocated

§Examples

use gen_vec::Index;
use gen_vec::exposed::IndexAllocator;

let mut allocator: IndexAllocator = IndexAllocator::new();
let index: Index = allocator.allocate();
assert!(allocator.is_active(index));
allocator.deallocate(index);
assert!(!allocator.is_active(index));

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pub fn num_free(&self) -> usize

Returns the number of free indices waiting to be allocated and reused

§Examples

use gen_vec::Index;
use gen_vec::exposed::IndexAllocator;

let mut allocator: IndexAllocator = IndexAllocator::new();
assert_eq!(allocator.num_free(), 0);

let index: Index = allocator.allocate();

allocator.deallocate(index);
assert_eq!(allocator.num_free(), 1);

let index: Index = allocator.allocate();
assert_eq!(allocator.num_free(), 0);

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pub fn num_active(&self) -> usize

Returns the number of active indices

§Examples

use gen_vec::Index;
use gen_vec::exposed::IndexAllocator;

let mut allocator: IndexAllocator = IndexAllocator::new();
assert_eq!(allocator.num_active(), 0);

let index: Index = allocator.allocate();
assert_eq!(allocator.num_active(), 1);

allocator.deallocate(index);
assert_eq!(allocator.num_active(), 0);

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pub fn iter(&self) -> Iter<'_> ⓘ

Returns an iterator over an immutable IndexAllocator Each step returns an Index

§Examples

use gen_vec::Index;
use gen_vec::exposed::IndexAllocator;

let mut allocator: IndexAllocator = IndexAllocator::new();
allocator.allocate();
allocator.allocate();

for index in allocator
{
    println!("{:?}", index);
}