src/pagenode.h

   1 #include <stdlib.h> //malloc
   2
   3 extern //apc.c
   4 long sys_pagesize;
   5
   6 #define SYS_PAGESIZE     (sys_pagesize)
   7 #define NAME_PAGESIZE    (APC_NAME_MAX * 1024)
   8 #define PL_HEADERSIZE    (sizeof(struct pagenode_header_t))
   9 #define PL_HEADSIZE(_PL) (_PL.head->header.head - _PL.head->root)
  10 #define PL_HEADMEM(_PL)  (_PL.pagesize - PL_HEADERSIZE - PL_HEADSIZE(_PL))
  11 #define  struct_clear(_S) (memset((_S), 0, sizeof(*(_S))))
  12 /* Memory allocation structures */
  13 struct pagenode_t;
  14 struct pagenode_header_t {
  15   struct pagenode_t* next;
  16   char*              head;
  17 };
  18 struct pagenode_t {
  19   struct pagenode_header_t header;
  20   char                     root[];
  21 };
  22 struct pagelist_t {
  23   struct pagenode_t* root, * head;
  24   size_t             pagesize;
  25 };
  26
  27 static
  28 void*    stack_alloc(struct pagelist_t*, size_t);
  29 static inline
  30 void*    pagelist_pop(struct pagelist_t*,size_t);
  31 #define $($)#$
  32 #define  pagelist_alloc(pagelist) do {                                  \
  33     pagelist.head->header.next = (struct pagenode_t*) malloc(pagelist.pagesize); \
  34     if (pagelist.head->header.next == NULL)                             \
  35       eprintf("Memory allocation error\n");                             \
  36     struct_clear(pagelist.head->header.next);                           \
  37     pagelist.head = pagelist.head->header.next;                         \
  38     pagelist.head->header.head = pagelist.head->root;                   \
  39   } while (0)
  40 #define  pagelist_init(pagelist,size) do {                      \
  41     pagelist.pagesize = size;                                   \
  42     pagelist.root = (struct pagenode_t*) malloc(size);          \
  43     if (pagelist.root == NULL)                                  \
  44       eprintf("Memory allocation error\n");                     \
  45     struct_clear(pagelist.root);                                \
  46     pagelist.head = pagelist.root;                              \
  47     pagelist.head->header.head = pagelist.head->root;           \
  48   } while (0)
  49 static
  50 void     pagenode_free(struct pagenode_t*);
  51
  52 static inline
  53 void* pagelist_pop
  54 ( struct pagelist_t* pagelist,
  55   size_t             size
  56 )
  57 { size_t headsize = PL_HEADSIZE((*pagelist));
  58   if (!headsize)
  59     { free(pagelist->head);
  60       pagelist->head = pagelist->root;
  61       while (pagelist->head->header.next != NULL)
  62         pagelist->head = pagelist->head->header.next;
  63     }
  64   if (headsize < size)
  65     eprintf("Attempted to pop unaligned value from pagelist\n");
  66   pagelist->head->header.head -= size;
  67   return pagelist->head->header.head;
  68 }
  69
  70 /* Recursively clean pagenode linked list, freeing last first */
  71 static
  72 void pagenode_free
  73 ( struct pagenode_t* pagenode )
  74 { if (pagenode->header.next != NULL)
  75     pagenode_free(pagenode->header.next);
  76   free(pagenode);
  77 }
  78 static
  79 void* stack_alloc
  80 ( struct pagelist_t* pagelist,
  81   size_t bytes )
  82 { void* p;
  83   if (PL_HEADMEM((*pagelist)) < bytes)
  84     pagelist_alloc((*pagelist));
  85   p = pagelist->head->header.head;
  86   pagelist->head->header.head += bytes;
  87   return p;
  88 }