#pragma once
#include "core.h"

typedef union APoolElement APoolElement;
union APoolElement {
    APoolElement *next;       // offset from start to next free block (when not allocated)
};

typedef struct APool APool;
struct APool {
    APoolElement *free_list;  // free list
    U8 *start;                // start of user buffer
    Allocator *allocator;
    U32 element_size;         // aligned size of each block
    U32 n_elements;           // total number of blocks
    U32 align;                // alignment
};
enum {
    APOOL_AUTOGROW = 0
};

#define apool_create(arena, n_elements, type) \
        apool_create_ex(arena, n_elements, sizeof(type), alignof(type));
APool *apool_create_ex(Allocator *allocator, U32 n_elements, U32 element_size, uint32_t element_align);
void *apool_alloc(APool *pool);
void apool_free(APool *pool, void *element);