Struct SegregatedBumpAllocator 

pub struct SegregatedBumpAllocator;

Minimal Allocator with Fixed Bins + Bump Pointer Fallback.

极简固定分箱 + Bump Pointer 回退分配器。

Design Philosophy

• Extreme Size: Abandon Coalescing and Splitting, remove all complex list traversals and metadata headers.
• Speed First: Small object allocation/deallocation are strictly O(1).
• Use Cases: Wasm Serverless functions, short-lived scripts, or scenarios with ample memory but sensitive to startup speed/size.

设计哲学

• 极简体积：放弃合并（Coalescing）与拆分（Splitting），移除所有复杂的链表遍历和元数据头。
• 速度优先：小对象分配/释放均为严格的 O(1)。
• 场景定位：Wasm Serverless 函数、短生命周期脚本、或内存充裕但对启动速度/体积敏感的场景。

Memory Layout

• Bin 0: 16 Bytes (for Box, small structs)
• Bin 1: 32 Bytes
• Bin 2: 64 Bytes
• Bin 3: 128 Bytes
• Large: > 128 Bytes, allocated directly using Bump Pointer, not reused.

内存布局

• Bin 0: 16 Bytes (用于 Box, small structs)
• Bin 1: 32 Bytes
• Bin 2: 64 Bytes
• Bin 3: 128 Bytes
• Large: > 128 Bytes，直接使用 Bump Pointer 分配，不复用。

Implementations

impl SegregatedBumpAllocator

pub const fn new() -> Self

pub unsafe fn reset()

⚠️ Test/Bench only: Reset global state

⚠️ 仅用于测试/Bench：重置全局状态

Trait Implementations

impl GlobalAlloc for SegregatedBumpAllocator

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.

impl Sync for SegregatedBumpAllocator

Safety Warning: Allocators in this module are designed for [Single Threaded] environments. Sync is implemented only to satisfy GlobalAlloc trait requirements. Using this allocator in a multi-threaded environment will lead to Undefined Behavior (UB). Please ensure it is used only in single-threaded environments (e.g., WASM or single-threaded embedded).

安全性警示 (Safety Warning): 本模块中的分配器均为【单线程】设计。 实现了 Sync 仅为了满足 GlobalAlloc trait 的要求。 在多线程环境中使用此分配器会导致未定义行为 (UB)。 请确保只在单线程环境（如 WASM 或单线程嵌入式环境）中使用。