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/*
* malloc.h
*
* Internals for the memory allocator
*/
#include <stdint.h>
#include <stddef.h>
/*
* This is the minimum chunk size we will ask the kernel for; this should
* be a multiple of the page size on all architectures.
*/
#define MALLOC_CHUNK_SIZE 65536
#define MALLOC_CHUNK_MASK (MALLOC_CHUNK_SIZE-1)
struct free_arena_header;
/*
* This structure should be a power of two. This becomes the
* alignment unit.
*/
struct arena_header {
void *tag;
size_t attrs; /* Bits 0..1: Type, 2..3: Unused, 4..31: MSB of the size */
struct free_arena_header *next, *prev;
};
#define ARENA_TYPE_USED 0x0
#define ARENA_TYPE_FREE 0x1
#define ARENA_TYPE_HEAD 0x2
#ifdef DEBUG_MALLOC
#define ARENA_TYPE_DEAD 0x3
#endif
#define ARENA_SIZE_MASK (~(uintptr_t)(sizeof(struct arena_header)-1))
#define ARENA_TYPE_MASK ((size_t)0x3)
#define ARENA_ALIGN_UP(p) ((char *)(((uintptr_t)(p) + ~ARENA_SIZE_MASK) & ARENA_SIZE_MASK))
#define ARENA_ALIGN_DOWN(p) ((char *)((uintptr_t)(p) & ARENA_SIZE_MASK))
#define ARENA_SIZE_GET(attrs) ((attrs) & ARENA_SIZE_MASK)
#define ARENA_TYPE_GET(attrs) ((attrs) & ARENA_TYPE_MASK)
#define ARENA_SIZE_SET(attrs, size) \
((attrs) = ((size) & ARENA_SIZE_MASK) | ((attrs) & ~ARENA_SIZE_MASK))
#define ARENA_TYPE_SET(attrs, type) \
((attrs) = ((attrs) & ~ARENA_TYPE_MASK) | ((type) & ARENA_TYPE_MASK))
/*
* This structure should be no more than twice the size of the
* previous structure.
*/
struct free_arena_header {
struct arena_header a;
struct free_arena_header *next_free, *prev_free;
};
extern struct free_arena_header __malloc_head;
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