backend/dvi/mdvi-lib/list.c

   1 /*
   2  * Copyright (C) 2000, Matias Atria
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  17  */
  18
  19 #include "common.h"
  20
  21 void    listh_init(ListHead *head)
  22 {
  23         head->head = head->tail = NULL;
  24         head->count = 0;
  25 }
  26
  27 void    listh_prepend(ListHead *head, List *list)
  28 {
  29         list->prev = NULL;
  30         list->next = head->head;
  31         if(head->head)
  32                 head->head->prev = list;
  33         head->head = list;
  34         if(!head->tail)
  35                 head->tail = list;
  36         head->count++;
  37 }
  38
  39 void    listh_append(ListHead *head, List *list)
  40 {
  41         list->next = NULL;
  42         list->prev = head->tail;
  43         if(head->tail)
  44                 head->tail->next = list;
  45         else
  46                 head->head = list;
  47         head->tail = list;
  48         head->count++;
  49 }
  50
  51 void    listh_add_before(ListHead *head, List *at, List *list)
  52 {
  53         if(at == head->head || head->head == NULL)
  54                 listh_prepend(head, list);
  55         else {
  56                 list->next = at;
  57                 list->prev = at->prev;
  58                 at->prev = list;
  59                 head->count++;
  60         }
  61 }
  62
  63 void    listh_add_after(ListHead *head, List *at, List *list)
  64 {
  65         if(at == head->tail || !head->tail)
  66                 listh_append(head, list);
  67         else {
  68                 list->prev = at;
  69                 list->next = at->next;
  70                 at->next = list;
  71                 head->count++;
  72         }
  73 }
  74
  75 void    listh_remove(ListHead *head, List *list)
  76 {
  77         if(list == head->head) {
  78                 head->head = list->next;
  79                 if(head->head)
  80                         head->head->prev = NULL;
  81         } else if(list == head->tail) {
  82                 head->tail = list->prev;
  83                 if(head->tail)
  84                         head->tail->next = NULL;
  85         } else {
  86                 list->next->prev = list->prev;
  87                 list->prev->next = list->next;
  88         }
  89         if(--head->count == 0)
  90                 head->head = head->tail = NULL;
  91 }
  92
  93 void    listh_concat(ListHead *h1, ListHead *h2)
  94 {
  95         if(h2->head == NULL)
  96                 ; /* do nothing */
  97         else if(h1->tail == NULL)
  98                 h1->head = h2->head;
  99         else {
 100                 h1->tail->next = h2->head;
 101                 h2->head->prev = h1->tail;
 102         }
 103         h1->tail = h2->tail;
 104         h1->count += h2->count;
 105 }
 106
 107 void    listh_catcon(ListHead *h1, ListHead *h2)
 108 {
 109         if(h2->head == NULL)
 110                 ; /* do nothing */
 111         else if(h1->head == NULL)
 112                 h1->tail = h2->tail;
 113         else {
 114                 h1->head->prev = h2->tail;
 115                 h2->tail->next = h1->head;
 116         }
 117         h1->head = h2->head;
 118         h1->count += h2->count;
 119 }