src/add-ons/kernel/file_systems/googlefs/lists2.c

   1 /*
   2  * Copyright 2004-2008, François Revol, <revol@free.fr>.
   3  * Distributed under the terms of the MIT License.
   4  */
   5
   6 #include <OS.h>
   7 #include "lists2.h"
   8
   9 void *sll_find(long nextoff, void *head, sll_compare_func func, void *id)
  10 {
  11         void *p = head;
  12         int count = 5000;
  13         if (head == NULL)
  14                 return NULL;
  15         while (p) {
  16                 if (func(p, id) == 0)
  17                         return p;
  18                 p = sll_next(nextoff, p);
  19                 if (!count--) {
  20                         dprintf("sll_find: WARNING: 5000 nodes to search ??? looks more of a loop.\n");
  21                         return NULL;
  22                 }
  23         }
  24         return NULL;
  25 }
  26
  27 status_t sll_insert_head(long nextoff, void **head, void *item)
  28 {
  29         void *next = NULL;
  30         if (head == NULL || item == NULL)
  31                 return EINVAL;
  32         if (*head)
  33                 next = *head;
  34         *(void **)(((char *)item)+nextoff) = next;
  35         *head = item;
  36         return B_OK;
  37 }
  38
  39 status_t sll_insert_tail(long nextoff, void **head, void *item)
  40 {
  41         void *p, *next = NULL;
  42         if (head == NULL || item == NULL)
  43                 return EINVAL;
  44
  45         if (*(void **)(((char *)item)+nextoff)) {
  46                 dprintf("sll_insert_tail: WARNING: %p->next NOT NULL\n", item);
  47                 *(void **)(((char *)item)+nextoff) = NULL;
  48         }
  49
  50         p = *head;
  51         if (!p) {
  52                 *head = item;
  53                 return B_OK;
  54         }
  55         while (sll_next(nextoff, p))
  56                 p = sll_next(nextoff, p);
  57         *(void **)(((char *)p)+nextoff) = item;
  58         return B_OK;
  59 }
  60
  61 void *sll_dequeue_tail(long nextoff, void **head)
  62 {
  63         void **prev = NULL;
  64         void *curr = NULL;
  65         if (head == NULL || *head == NULL)
  66                 return NULL;
  67         prev = head;
  68         curr = *head;
  69         while (sll_next(nextoff, curr)) {
  70                 prev = (void **)(((char *)curr)+nextoff);
  71                 curr = sll_next(nextoff, curr);
  72         }
  73         *prev = NULL;
  74         return curr;
  75 }
  76
  77 status_t sll_remove(long nextoff, void **head, void *item)
  78 {
  79         void **prev = NULL;
  80         void *curr = NULL;
  81         if (head == NULL || *head == NULL || item == NULL)
  82                 return EINVAL;
  83         prev = head;
  84         curr = *head;
  85         while (prev && curr) {
  86                 if (curr == item) {
  87                         *prev = sll_next(nextoff, curr);
  88                         *(void **)(((char *)item)+nextoff) = NULL;
  89                         return B_OK;
  90                 }
  91                 prev = (void **)(((char *)curr)+nextoff);
  92                 curr = sll_next(nextoff, curr);
  93         }
  94         return ENOENT;
  95 }
  96
  97 void *sll_next(long nextoff, void *item)
  98 {
  99         void *next;
 100         if (!item)
 101                 return NULL;
 102         next = *(void **)(((char *)item)+nextoff);
 103         return next;
 104 }