// SPDX-License-Identifier: MPL-2.0
// This is the implementation for the slab allocator for sh_pez_REGION_VIRTUAL_OBJECT
#ifndef SH_LIB_SLAB_REG_VIRT_H
#define SH_LIB_SLAB_REG_VIRT_H
#include "std/type.h"
#include "std/status.h"
#include "memory/page.h"
#include "memory/vmem_layout.h"
#define SH_SLAB_REG_VIRT_DATA_VA SH_VMEM_LAYOUT_SLAB_REG_VIRT_VA
#define SH_SLAB_REG_VIRT_MAX_SLAB (sh_uint64)(512*1024)
#define SH_SLAB_REG_VIRT_SLAB_DATA_PAGES (sh_uint64)3
#define SH_SLAB_REG_VIRT_SLAB_DATA_SIZE_BYTES (sh_uint64)(SH_SLAB_REG_VIRT_SLAB_DATA_PAGES*4096)
#define SH_SLAB_REG_VIRT_OBJECT_SIZE_BYTES (sh_uint64)12
#define SH_SLAB_REG_VIRT_OBJECTS_PER_SLAB (sh_uint64)1024
#define SH_SLAB_REG_VIRT_ACTUAL_OBJECTS_PER_SLAB (sh_uint64)1023
#define SH_SLAB_REG_VIRT_SLAB_BITMAP_SIZE_BYTES (sh_uint64)(SH_SLAB_REG_VIRT_OBJECTS_PER_SLAB/8)
#define SH_SLAB_REG_VIRT_NULL_REF (sh_uint64)0
// Virtual region slab structure
typedef struct sh_slab_reg_virt_SLAB_STRUCT {
  sh_uint16 used_count;
  sh_uint32 slab_index;
  struct sh_slab_reg_virt_SLAB_STRUCT* next;
  struct sh_slab_reg_virt_SLAB_STRUCT* prev;
  sh_uint64 free_bitmap[16];
} sh_slab_reg_virt_SLAB_STRUCT;
#define SH_SLAB_REG_VIRT_HEADER_LIST_SIZE_BYTES SH_SLAB_REG_VIRT_MAX_SLAB*sizeof(sh_slab_reg_virt_SLAB_STRUCT)
// Virtual region object slab allocator structure
typedef struct {
  sh_slab_reg_virt_SLAB_STRUCT* slabs_header;
  sh_uint8* slabs_data;
  sh_uint32 max_slabs;
  sh_uint32 slab_count;
  sh_slab_reg_virt_SLAB_STRUCT* partial_head;
} sh_slab_reg_virt_SLAB_ALLOCATOR;
typedef sh_uint32 sh_slab_reg_virt_OBJECT_INDEX;
// Return slab index
#define SH_SLAB_REG_VIRT_REF_SLAB(ref) (sh_uint32)((ref)>>10)
// Return object index inside a slab
#define SH_SLAB_REG_VIRT_REF_OBJECT(ref) (sh_uint16)((ref) & 0x3FF)
// Make a valid object index from a slab index and an object index inside this slab
#define SH_SLAB_REG_VIRT_MAKE_REF(slab,obj) (((sh_slab_reg_virt_OBJECT_INDEX)(slab)<<10) | (sh_slab_reg_virt_OBJECT_INDEX)(obj))
// Initialize slab allocator structure. Does not allocate any slabs
SH_STATUS sh_slab_reg_virt_alloc_init(sh_slab_reg_virt_SLAB_ALLOCATOR* slab_alloc,sh_page_PAGE_TABLE_POOL *ptp);
// Allocate a new slab, initialize it and put it into the allocator. If new slab isn't the first to be allocated, push it on the partial slab list
SH_STATUS sh_slab_reg_virt_add_slab(sh_slab_reg_virt_SLAB_ALLOCATOR* alloc,sh_page_PAGE_TABLE_POOL *ptp,sh_slab_reg_virt_SLAB_STRUCT** out_slab);
// Obtain a pointer to the first partial slab. Does not scan the slabs. Allocate a new slab if necessary
SH_STATUS sh_slab_reg_virt_get_partial_slab(sh_slab_reg_virt_SLAB_ALLOCATOR* alloc,sh_page_PAGE_TABLE_POOL* ptp,sh_slab_reg_virt_SLAB_STRUCT** found_slab);
// Rescan all the slabs to set all metadatas in case of doubt. Does not modify alloc->slab_count, alloc->slabs_data
SH_STATUS sh_slab_reg_virt_scan_slabs(sh_slab_reg_virt_SLAB_ALLOCATOR* alloc);
// Return a valid 29 bits index to a empty object slot. Slabs allocation is automated by sh_slab_reg_virt_get_partial_slab
SH_STATUS sh_slab_reg_virt_find_free_object(sh_slab_reg_virt_SLAB_ALLOCATOR* alloc,sh_page_PAGE_TABLE_POOL *ptp,sh_slab_reg_virt_OBJECT_INDEX* out_ref);
// Return a pointer to referenced virtual region object
void* sh_slab_reg_virt_ref_to_ptr(sh_slab_reg_virt_SLAB_ALLOCATOR* alloc,sh_slab_reg_virt_OBJECT_INDEX ref);
// Allocate one new virtual region object. Return both a pointer to the struct of the new object and an index to access and deallocte the object. Since it call sh_slab_reg_virt_find_free_object, it can allocate new slab
SH_STATUS sh_slab_reg_virt_alloc(sh_slab_reg_virt_SLAB_ALLOCATOR* alloc,sh_page_PAGE_TABLE_POOL *ptp,sh_slab_reg_virt_OBJECT_INDEX* out_index);
// Dellocate one virtual region object provided as index.
SH_STATUS sh_slab_reg_virt_dealloc(sh_slab_reg_virt_SLAB_ALLOCATOR* alloc,sh_slab_reg_virt_OBJECT_INDEX index);
#endif