Module std::alloc

Allocators over storage the program owns: FixedBuffer serves Alloc from a byte buffer (no heap, usable in realtime code), and bump_alloc is the step to build your own bump allocator handler.

Source: std/alloc.weir; committed interface: std/alloc.iface. Index

• fn bump_alloc: One step of a bump allocator over the storage at base: the first block of l.size bytes aligned to l.align at or after offset *used, which it advances past the block.
• handler FixedBuffer: An Alloc handler that bumps through buf: with FixedBuffer(&mut bytes, 0) { … } serves every allocation in the block from bytes.

fn bump_alloc

pub fn bump_alloc<r>(base: Ptr<u8> in r, used: &mut usize, l: &Layout) -> Ptr<u8> in r

One step of a bump allocator over the storage at base: the first block of l.size bytes aligned to l.align at or after offset *used, which it advances past the block.

It does not check the end of the storage: the caller keeps the block inside it (a block past the end is reported out of range by the raw monitor) and turns it into a Mem with mem_from_ptr(p, l.size).

Committed interface (std/alloc.iface):

writes through used: everything

handler FixedBuffer

pub handler FixedBuffer(mut buf: &mut [u8], mut used: usize) for Alloc with Process

An Alloc handler that bumps through buf: with FixedBuffer(&mut bytes, 0) { … } serves every allocation in the block from bytes.

Allocation aborts the process (with Process) when the buffer is exhausted; free and resize do nothing, so memory is reclaimed only when the buffer is. No heap is touched, so it fits realtime code.

Handles Alloc, with clauses:

• tail fn alloc(l: Layout)
• tail fn free(m: Mem)
• tail fn resize(m: &mut Mem, l: Layout)