std.experimental.allocator.common

enum auto isAllocator(A);

Is true iff A is an allocator.

Examples:

import std.experimental.allocator.building_blocks.null_allocator : NullAllocator;
import std.experimental.allocator.mallocator : Mallocator;
import std.experimental.allocator.gc_allocator : GCAllocator;
import std.experimental.allocator.mmap_allocator : MmapAllocator;
static assert(isAllocator!NullAllocator);
static assert(isAllocator!Mallocator);
static assert(isAllocator!GCAllocator);
static assert(isAllocator!MmapAllocator);
static assert(!isAllocator!int);

template stateSize(T)

Returns the size in bytes of the state that needs to be allocated to hold an object of type T. stateSize!T is zero for structs that are not nested and have no nonstatic member variables.

enum auto hasStaticallyKnownAlignment(Allocator);

Returns true if the Allocator has the alignment known at compile time; otherwise it returns false.

enum ulong chooseAtRuntime;

chooseAtRuntime is a compile-time constant of type size_t that several parameterized structures in this module recognize to mean deferral to runtime of the exact value. For example, BitmappedBlock!(Allocator, 4096) (described in detail below) defines a block allocator with block size of 4096 bytes, whereas BitmappedBlock!(Allocator, chooseAtRuntime) defines a block allocator that has a field storing the block size, initialized by the user.

enum ulong unbounded;

unbounded is a compile-time constant of type size_t that several parameterized structures in this module recognize to mean "infinite" bounds for the parameter. For example, Freelist (described in detail below) accepts a maxNodes parameter limiting the number of freelist items. If unbounded is passed for maxNodes, then there is no limit and no checking for the number of nodes.

enum uint platformAlignment;

The alignment that is guaranteed to accommodate any D object allocation on the current platform.

size_t goodAllocSize(A)(auto ref A a, size_t n);

The default good size allocation is deduced as n rounded up to the allocator's alignment.

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

The default reallocate function first attempts to use expand. If Allocator.expand is not defined or returns false, reallocate allocates a new block of memory of appropriate size and copies data from the old block to the new block. Finally, if Allocator defines deallocate, reallocate uses it to free the old memory block.

reallocate does not attempt to use Allocator.reallocate even if defined. This is deliberate so allocators may use it internally within their own implementation of reallocate.

bool alignedReallocate(Allocator)(ref Allocator alloc, ref void[] b, size_t s, uint a)
if (hasMember!(Allocator, "alignedAllocate"));

The default alignedReallocate function first attempts to use expand. If Allocator.expand is not defined or returns false, alignedReallocate allocates a new block of memory of appropriate size and copies data from the old block to the new block. Finally, if Allocator defines deallocate, alignedReallocate uses it to free the old memory block.

alignedReallocate does not attempt to use Allocator.reallocate even if defined. This is deliberate so allocators may use it internally within their own implementation of reallocate.

string forwardToMember(string member, string[] funs...);

Forwards each of the methods in funs (if defined) to member.