Layout

struct Layout[T: AnyType, *, alignment: Alignment = Alignment.of[T]()]

Describes the shape of a memory allocation for elements of type T.

A Layout pairs the count of elements, held at runtime, with the alignment of the allocation, carried as a compile-time parameter. Passing a Layout to alloc and dealloc keeps the size and alignment requirements explicit and co-located at every call site, preventing mismatches between allocation and deallocation.

Example:

from std.memory.alloc import alloc, dealloc, Layout

# Allocate room for 8 Int32 values with `Int32`'s natural alignment.
var layout = Layout[Int32](count=8)
var allocation = alloc(layout)
# ... use allocation ...
dealloc(allocation^)

# Over-align the same storage to a 64-byte boundary.
var over_aligned = alloc(
    Layout[Int32, alignment = .of_bytes[64]()](count=8)
)
dealloc(over_aligned^)

Parameters

• ​T (AnyType): The element type the layout describes.
• ​alignment (Alignment): Byte alignment of the allocation.

Implemented traits

AnyType, Copyable, Deinitable, ImplicitlyCopyable, Movable, RegisterPassable, TrivialRegisterPassable, Writable

Methods

__init__

def __init__(*, count: Int) -> Self

Initializes a Layout describing count elements of type T.

Constraints:

alignment must be no smaller than align_of[T](). Alignment itself enforces the power-of-two requirement.

Args:

• ​count (Int): Number of elements of type T to describe.

single

static def single() -> Self

Creates a Layout for exactly one element of type T.

Example:

from std.memory.alloc import alloc, dealloc, Layout

var layout = Layout[Int64].single()
var allocation = alloc(layout)
allocation.unsafe_ptr().write(0)
dealloc(allocation^)

Returns:

Self: A Layout with count equal to 1.

as_byte_layout

def as_byte_layout(self) -> Layout[UInt8, alignment=alignment]

Converts this layout to an equivalent byte-level layout.

Multiplies the element count by size_of[T]() to express the same allocation in terms of raw bytes, preserving the alignment.

Returns:

Layout[UInt8, alignment=alignment]: A Layout[Byte, alignment=_] whose count is self.count() * size_of[T]().

count

def count(self) -> Int

Returns the number of elements described by this layout.

Returns:

Int: The element count passed at construction time.

write_to

def write_to(self, mut writer: T)

Writes a human-readable representation of this layout to writer.

Args:

• ​writer (T): The writer to write to.

write_repr_to

def write_repr_to(self, mut writer: T)

Writes a debug representation of this layout to writer.

Args:

• ​writer (T): The writer to write to.