Struct BumpAllocator 

pub struct BumpAllocator {
    pub start: usize,
    pub len: usize,
}

A bump allocator over the SVM heap region.

This is the same single-pass, never-frees design the Solana SDK and Pinocchio use: the first word of the heap stores the current cursor, allocations bump it downward from the top of the region, and dealloc is a no-op. It is the right allocator for the cold paths of a program that wants alloc (e.g. a Vec while building a CPI) while keeping the hot path zero-allocation. For programs that must never allocate, prefer no_allocator! so any stray allocation traps.

Install it with default_allocator!.

Fields

start: usize

Heap region start address.

len: usize

Heap region length in bytes.

Trait Implementations

impl GlobalAlloc for BumpAllocator

unsafe fn alloc(&self, layout: Layout) -> *mut u8

Allocates memory as described by the given layout.

unsafe fn dealloc(&self, _ptr: *mut u8, _layout: Layout)

Deallocates the block of memory at the given ptr pointer with the given layout.

unsafe fn alloc_zeroed(&self, layout: Layout) -> *mut u8

Behaves like alloc, but also ensures that the contents are set to zero before being returned.

unsafe fn realloc( &self, ptr: *mut u8, layout: Layout, new_size: usize, ) -> *mut u8

Shrinks or grows a block of memory to the given new_size in bytes. The block is described by the given ptr pointer and layout.