include/list_extra.h

   1 /**
   2  * @file list_extra.h
   3  *
   4  * @brief Extra handy list utils.
   5  *
   6  * @author Yury Georgievskiy. CERN AB/CO.
   7  *
   8  * @date May, 2008
   9  *
  10  * Can be used by the driver and in the user space.
  11  *
  12  * @version 1.0  ygeorgie  15/05/2008  Creation date.
  13  */
  14 #ifndef _LIST_EXTRA_H_INCLUDE_
  15 #define _LIST_EXTRA_H_INCLUDE_
  16
  17 #if defined (__linux__) && defined(__KERNEL__)
  18 /* for kernel only */
  19 #include <linux/kernel.h>
  20 #include <linux/list.h>
  21 #include <linux/version.h>
  22 #endif
  23
  24 #if !defined(__KERNEL__) && !defined(__LYNXOS)
  25 /* for user-space only */
  26 #define kfree free
  27 #endif
  28
  29 //!< A way to declare list in a header file
  30 #define DECLARE_GLOB_LIST_HEAD(list_name) \
  31 _DECL struct list_head list_name _INIT(LIST_HEAD_INIT(list_name))
  32
  33 /**
  34  * list_capacity - how many elements in the list
  35  *
  36  * @head: the list to test.
  37  */
  38 static inline int list_capacity(struct list_head *head)
  39 {
  40         int cntr = 0;
  41         struct list_head *at = head;
  42
  43         while (at->next != head) {
  44                 at = at->next;
  45                 ++cntr;
  46         }
  47
  48         return cntr;
  49 }
  50
  51 /**
  52  * list_next - pointer to the next element in the list
  53  *
  54  * @head: current list element
  55  */
  56 static inline struct list_head* list_next(struct list_head *head)
  57 {
  58         return head->next;
  59 }
  60
  61
  62 /**
  63  * list_prev - pointer to the previous element in the list
  64  *
  65  * @head: current list element
  66  */
  67 static inline struct list_head* list_prev(struct list_head *head)
  68 {
  69         return head->prev;
  70 }
  71
  72
  73 /**
  74  * list_idx - get element of the list
  75  *
  76  * @head: the list in question
  77  * @idx:  list element index (starting from 0) to get
  78  */
  79 static inline struct list_head* list_idx(struct list_head *head, int idx)
  80 {
  81         int cntr = 0;
  82         struct list_head *at = NULL;
  83
  84         list_for_each(at, head) {
  85                 if (cntr++ == idx)
  86                         break;
  87         }
  88         return at;
  89 }
  90
  91
  92 /**
  93  * list_free_all_safe - delete and free all elements safe from the list
  94  *
  95  * All list elements should be allocated entities only!
  96  *
  97  * @head:   the head for your list
  98  * @type:   the type of the struct this is embedded in
  99  * @member: the name of the list_struct within the struct
 100  */
 101 #define list_free_all_safe(head, type, member)                  \
 102 do {                                                            \
 103         type *__element;                                        \
 104         struct list_head *__list, *__safe;                      \
 105                                                                 \
 106         list_for_each_safe(__list, __safe, head) {              \
 107                 __element = list_entry(__list, type, member);   \
 108                 list_del(&__element->member);                   \
 109                 kfree(__element);                               \
 110         }                                                       \
 111  } while (0)
 112
 113
 114 #ifndef list_last_entry
 115 #define list_last_entry(ptr, type, member) \
 116         list_entry((ptr)->prev, type, member)
 117 #endif
 118
 119 #endif /* _LIST_EXTRA_H_INCLUDE_ */