libopkg/active_list.c

   1 /* active_list.h - the opkg package management system
   2
   3    Tick Chen <tick@openmoko.com>
   4
   5    Copyright (C) 2008 Openmoko Inc.
   6
   7    This program is free software; you can redistribute it and/or
   8    modify it under the terms of the GNU General Public License as
   9    published by the Free Software Foundation; either version 2, or (at
  10    your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful, but
  13    WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15    General Public License for more details.
  16 */
  17
  18
  19 #include "active_list.h"
  20 #include <stdio.h>
  21 #include <string.h>
  22 #include <stdlib.h>
  23
  24
  25 void active_list_init(struct active_list *ptr) {
  26     INIT_LIST_HEAD(&ptr->node);
  27     INIT_LIST_HEAD(&ptr->depend);
  28     ptr->depended = NULL;
  29 }
  30
  31 /**
  32  */
  33 struct active_list * active_list_next(struct active_list *head, struct active_list *ptr) {
  34     struct active_list *next=NULL;
  35     if ( !head ) {
  36         fprintf(stderr, "active_list_next head = %p, ptr = %p invalid value!!\n", head, ptr);
  37         return NULL;
  38     }
  39     if ( !ptr )
  40         ptr = head;
  41     next = list_entry(ptr->node.next, struct active_list, node);
  42     if ( next == head ) {
  43         return NULL;
  44     }
  45     if ( ptr->depended && &ptr->depended->depend == ptr->node.next ) {
  46         return ptr->depended;
  47     }
  48     while ( next->depend.next != &next->depend ) {
  49         next = list_entry(next->depend.next, struct active_list, node);
  50     }
  51     return next;
  52 }
  53
  54
  55 struct active_list * active_list_prev(struct active_list *head, struct active_list *ptr) {
  56     struct active_list *prev=NULL;
  57     if ( !head ) {
  58         fprintf(stderr, "active_list_prev head = %p, ptr = %p invalid value!!\n", head, ptr);
  59         return NULL;
  60     }
  61     if ( !ptr )
  62         ptr = head;
  63     if ( ptr->depend.prev != &ptr->depend ) {
  64         prev = list_entry(ptr->depend.prev, struct active_list, node);
  65         return prev;
  66     }
  67     if ( ptr->depended  && ptr->depended != head && &ptr->depended->depend == ptr->node.prev ) {
  68         prev = list_entry(ptr->depended->node.prev, struct active_list, node);
  69     } else
  70         prev = list_entry(ptr->node.prev, struct active_list, node);
  71     if ( prev == head )
  72         return NULL;
  73     return prev;
  74 }
  75
  76
  77 struct active_list *active_list_move_node(struct active_list *old_head, struct active_list *new_head, struct active_list *node) {
  78     struct active_list *prev;
  79     if (!old_head || !new_head || !node)
  80         return NULL;
  81     if (old_head == new_head)
  82         return node;
  83     prev = active_list_prev(old_head, node);
  84     active_list_add(new_head, node);
  85     return prev;
  86 }
  87
  88 static void list_head_clear (struct list_head *head) {
  89     struct active_list *next;
  90     struct list_head *n, *ptr;
  91     if (!head)
  92         return;
  93     list_for_each_safe(ptr, n , head) {
  94         next = list_entry(ptr, struct active_list, node);
  95         if (next->depend.next != &next->depend) {
  96             list_head_clear(&next->depend);
  97         }
  98         active_list_init(next);
  99     }
 100 }
 101 void active_list_clear(struct active_list *head) {
 102     list_head_clear(&head->node);
 103     if (head->depend.next != &head->depend) {
 104         list_head_clear(&head->depend);
 105     }
 106     active_list_init(head);
 107 }
 108
 109 void active_list_add_depend(struct active_list *node, struct active_list *depend) {
 110     list_del_init(&depend->node);
 111     list_add_tail(&depend->node, &node->depend);
 112     depend->depended  = node;
 113 }
 114
 115 void active_list_add(struct active_list *head, struct active_list *node) {
 116     list_del_init(&node->node);
 117     list_add_tail(&node->node, &head->node);
 118     node->depended  = head;
 119 }
 120
 121 struct active_list * active_list_head_new() {
 122     struct active_list * head = calloc(1, sizeof(struct active_list));
 123     active_list_init(head);
 124     return head;
 125 }
 126
 127 void active_list_head_delete(struct active_list *head) {
 128     active_list_clear(head);
 129     free(head);
 130 }
 131
 132 /*
 133  *  Using insert sort.
 134  *  Note. the list should not be large, or it will be very inefficient.
 135  *
 136  */
 137 struct active_list * active_list_sort(struct active_list *head, int (*compare)(const void *, const void *)) {
 138     struct active_list tmphead;
 139     struct active_list *node, *ptr;
 140     if ( !head )
 141         return NULL;
 142     active_list_init(&tmphead);
 143     for (node = active_list_next(head, NULL); node; node = active_list_next(head, NULL)) {
 144         if (tmphead.node.next == &tmphead.node) {
 145             active_list_move_node(head, &tmphead, node);
 146         } else {
 147             for (ptr = active_list_next(&tmphead, NULL); ptr; ptr=active_list_next(&tmphead, ptr)) {
 148                 if (compare(ptr, node) <= 0) {
 149                     break;
 150                 }
 151             }
 152             if (!ptr) {
 153                 active_list_move_node(head, &tmphead, node);
 154             } else {
 155                 active_list_move_node(head, ptr, node);
 156             }
 157         }
 158         node->depended = &tmphead;
 159     }
 160     for (ptr = active_list_prev(&tmphead, NULL); ptr; ptr=active_list_prev(&tmphead, NULL)) {
 161         active_list_move_node(&tmphead, head, ptr);
 162     }
 163     return head;
 164 }