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 <config.h>
  20 #include "common.h"
  21
  22 void    listh_init(ListHead *head)
  23 {
  24         head->head = head->tail = NULL;
  25         head->count = 0;
  26 }
  27
  28 void    listh_prepend(ListHead *head, List *list)
  29 {
  30         list->prev = NULL;
  31         list->next = head->head;
  32         if(head->head)
  33                 head->head->prev = list;
  34         head->head = list;
  35         if(!head->tail)
  36                 head->tail = list;
  37         head->count++;
  38 }
  39
  40 void    listh_append(ListHead *head, List *list)
  41 {
  42         list->next = NULL;
  43         list->prev = head->tail;
  44         if(head->tail)
  45                 head->tail->next = list;
  46         else
  47                 head->head = list;
  48         head->tail = list;
  49         head->count++;
  50 }
  51
  52 void    listh_add_before(ListHead *head, List *at, List *list)
  53 {
  54         if(at == head->head || head->head == NULL)
  55                 listh_prepend(head, list);
  56         else {
  57                 list->next = at;
  58                 list->prev = at->prev;
  59                 at->prev = list;
  60                 head->count++;
  61         }
  62 }
  63
  64 void    listh_add_after(ListHead *head, List *at, List *list)
  65 {
  66         if(at == head->tail || !head->tail)
  67                 listh_append(head, list);
  68         else {
  69                 list->prev = at;
  70                 list->next = at->next;
  71                 at->next = list;
  72                 head->count++;
  73         }
  74 }
  75
  76 void    listh_remove(ListHead *head, List *list)
  77 {
  78         if(list == head->head) {
  79                 head->head = list->next;
  80                 if(head->head)
  81                         head->head->prev = NULL;
  82         } else if(list == head->tail) {
  83                 head->tail = list->prev;
  84                 if(head->tail)
  85                         head->tail->next = NULL;
  86         } else {
  87                 list->next->prev = list->prev;
  88                 list->prev->next = list->next;
  89         }
  90         if(--head->count == 0)
  91                 head->head = head->tail = NULL;
  92 }
  93
  94 void    listh_concat(ListHead *h1, ListHead *h2)
  95 {
  96         if(h2->head == NULL)
  97                 ; /* do nothing */
  98         else if(h1->tail == NULL)
  99                 h1->head = h2->head;
 100         else {
 101                 h1->tail->next = h2->head;
 102                 h2->head->prev = h1->tail;
 103         }
 104         h1->tail = h2->tail;
 105         h1->count += h2->count;
 106 }
 107
 108 void    listh_catcon(ListHead *h1, ListHead *h2)
 109 {
 110         if(h2->head == NULL)
 111                 ; /* do nothing */
 112         else if(h1->head == NULL)
 113                 h1->tail = h2->tail;
 114         else {
 115                 h1->head->prev = h2->tail;
 116                 h2->tail->next = h1->head;
 117         }
 118         h1->head = h2->head;
 119         h1->count += h2->count;
 120 }