ScopedAllocator

ScopedAllocator delegates all allocation requests to ParentAllocator. When destroyed, the ScopedAllocator object automatically calls deallocate for all memory allocated through its lifetime. (The deallocateAll function is also implemented with the same semantics.)

deallocate is also supported, which is where most implementation effort and overhead of ScopedAllocator go. If deallocate is not needed, a simpler design combining AllocatorList with Region is recommended.

struct ScopedAllocator (

ParentAllocator

) {

struct AffixAllocator(Allocator, Prefix, Suffix = void) via import std.experimental.allocator.building_blocks.affix_allocator : AffixAllocator;;

eponymoustemplate hasMember(T, string name) via import std.traits : hasMember;;

struct Ternary via import std.typecons : Ternary;;

static if(stateSize!ParentAllocator)

size_t goodAllocSize(size_t n);

void[] allocate(size_t n);

static if(hasMember!(Allocator, "expand"))

bool expand(void[] b, size_t delta);

bool reallocate(void[] b, size_t s);

static if(hasMember!(Allocator, "owns"))

Ternary owns(void[] b);

static if(hasMember!(Allocator, "deallocate"))

bool deallocate(void[] b);

bool deallocateAll();

Ternary empty();

}

Destructor

~this ~this(): ScopedAllocator's destructor releases all memory allocated during its lifetime.

Postblit

this(this) this(this): ScopedAllocator is not copyable.

Members

Functions

allocate void[] allocate(size_t n): Allocates memory. For management it actually allocates extra memory from the parent.
deallocate bool deallocate(void[] b): Deallocates b.
deallocateAll bool deallocateAll(): Deallocates all memory allocated.
empty Ternary empty(): Returns Ternary.yes if this allocator is not responsible for any memory, Ternary.no otherwise. (Never returns Ternary.unknown.)
expand bool expand(void[] b, size_t delta): Forwards to parent.expand(b, delta).
goodAllocSize size_t goodAllocSize(size_t n): Forwards to parent.goodAllocSize (which accounts for the management overhead).
owns Ternary owns(void[] b): Forwards to parent.owns(b).
reallocate bool reallocate(void[] b, size_t s): Reallocates b to new size s.

Manifest constants

alignment enum alignment;: Alignment offered

Variables

parent Allocator parent;: If ParentAllocator is stateful, parent is a property giving access to an AffixAllocator!ParentAllocator. Otherwise, parent is an alias for AffixAllocator!ParentAllocator.instance.

Examples

import std.experimental.allocator.mallocator : Mallocator;
import std.typecons : Ternary;
ScopedAllocator!Mallocator alloc;
assert(alloc.empty == Ternary.yes);
const b = alloc.allocate(10);
assert(b.length == 10);
assert(alloc.empty == Ternary.no);

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