LXR syslinux/dos/malloc.h

   1/*
   2 * malloc.h
   3 *
   4 * Internals for the memory allocator
   5 */
   6
   7#include <stdint.h>
   8#include <stddef.h>
   9
  10/*
  11 * This is the minimum chunk size we will ask the kernel for; this should
  12 * be a multiple of the page size on all architectures.
  13 */
  14#define MALLOC_CHUNK_SIZE       65536
  15#define MALLOC_CHUNK_MASK       (MALLOC_CHUNK_SIZE-1)
  16
  17/*
  18 * This structure should be a power of two.  This becomes the
  19 * alignment unit.
  20 */
  21struct free_arena_header;
  22
  23struct arena_header {
  24    size_t type;
  25    size_t size;                /* Also gives the location of the next entry */
  26    struct free_arena_header *next, *prev;
  27};
  28
  29#ifdef DEBUG_MALLOC
  30#define ARENA_TYPE_USED 0x64e69c70
  31#define ARENA_TYPE_FREE 0x012d610a
  32#define ARENA_TYPE_HEAD 0x971676b5
  33#define ARENA_TYPE_DEAD 0xeeeeeeee
  34#else
  35#define ARENA_TYPE_USED 0
  36#define ARENA_TYPE_FREE 1
  37#define ARENA_TYPE_HEAD 2
  38#endif
  39
  40#define ARENA_SIZE_MASK (sizeof(struct arena_header)-1)
  41
  42#define ARENA_ALIGN_UP(p)       ((char *)(((uintptr_t)(p) + ARENA_SIZE_MASK) & ~ARENA_SIZE_MASK))
  43#define ARENA_ALIGN_DOWN(p)     ((char *)((uintptr_t)(p) & ~ARENA_SIZE_MASK))
  44
  45/*
  46 * This structure should be no more than twice the size of the
  47 * previous structure.
  48 */
  49struct free_arena_header {
  50    struct arena_header a;
  51    struct free_arena_header *next_free, *prev_free;
  52};
  53
  54extern struct free_arena_header __malloc_head;
  55