cKit/Memory/c_ArenaAllocator.h

#ifndef INCLUDED_C_ARENAALLOCATOR_H
#define INCLUDED_C_ARENAALLOCATOR_H

#ifndef INCLUDED_C_ALLOCATOR_H
#include <c_Allocator.h>
#endif /*INCLUDED_C_ALLOCATOR_H*/


#ifndef INCLUDED_C_ARENA_H
#include <c_Arena.h>
#endif /*INCLUDED_C_ARENA_H*/


/* ------------------------------------------------------------------------------------------------------------------ */
/*  */

typedef struct {
    c_Arena_t* arena;
}c_ArenaAllocator_t;

/* ------------------------------------------------------------------------------------------------------------------ */
/*  */

C_STATIC_FORCE_INLINE
void c_ArenaAllocator_Init(c_ArenaAllocator_t* self, c_Arena_t* arena) {
    self->arena = arena;
}

/* ------------------------------------------------------------------------------------------------------------------ */
/*  */


C_STATIC_FORCE_INLINE
C_ALLOCATOR_ALLOC_FN(c_ArenaAllocator_Alloc) {
    c_ArenaAllocator_t* self = (c_ArenaAllocator_t*)ud;
    if (!self || !self->arena) return NULL;
    return c_Arena_Alloc(self->arena, (int)nBytes);
}

C_STATIC_FORCE_INLINE
C_ALLOCATOR_FREE_FN(c_ArenaAllocator_Free) {
    c_ArenaAllocator_t* self = (c_ArenaAllocator_t*)ud;
    if (!self || !self->arena) return;
    c_Arena_Free(self->arena, ptr);
}

C_STATIC_FORCE_INLINE
C_ALLOCATOR_REALLOC_FN(c_ArenaAllocator_Realloc) {
    c_ArenaAllocator_t* self = (c_ArenaAllocator_t*)ud;
    if (!self || !self->arena) return NULL;

    // 情况 1: 指针为空，直接分配新内存
    if (!ptr) {
        return c_Arena_Alloc(self->arena, (int)nNewSize);
    }

    // 情况 2: 新大小为 0，直接释放内存
    if (nNewSize==0) {
        c_Arena_Free(self->arena, ptr);
        return NULL;
    }


    // 情况 3: 伙伴块大小不匹配（需要升级或降级阶数），申请新块
    return c_Arena_Resize(self->arena, ptr, nOldSize, nNewSize);
}

/* ------------------------------------------------------------------------------------------------------------------ */
/*  */

C_STATIC_FORCE_INLINE
c_Allocator_t c_ArenaAllocator_Build(c_ArenaAllocator_t* self, c_Arena_t* arena) {
    c_ArenaAllocator_Init(self, arena);
    c_Allocator_t allocator={0};
    allocator.ud = self;
    allocator.alloc = c_ArenaAllocator_Alloc;
    allocator.free = c_ArenaAllocator_Free;
    allocator.realloc = c_ArenaAllocator_Realloc;
    return allocator;
}

#endif /*INCLUDED_C_ARENAALLOCATOR_H*/