libdockapp/src/list.c

   1 /* Generic single linked list to keep various information
   2    Copyright (C) 1993, 1994 Free Software Foundation, Inc.
   3
   4
   5 Author: Kresten Krab Thorup
   6
   7 Many modifications by Alfredo K. Kojima
   8
   9
  10 This file is part of GNU CC.
  11
  12 GNU CC is free software; you can redistribute it and/or modify
  13 it under the terms of the GNU General Public License as published by
  14 the Free Software Foundation; either version 2, or (at your option)
  15 any later version.
  16
  17 GNU CC is distributed in the hope that it will be useful,
  18 but WITHOUT ANY WARRANTY; without even the implied warranty of
  19 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20 GNU General Public License for more details.
  21
  22 You should have received a copy of the GNU General Public License
  23 along with GNU CC; see the file COPYING.  If not, write to
  24 the Free Software Foundation, 51 Franklin Street, Fifth Floor,
  25 Boston, MA 02110-1301 USA.  */
  26
  27 /* As a special exception, if you link this library with files compiled with
  28    GCC to produce an executable, this does not cause the resulting executable
  29    to be covered by the GNU General Public License. This exception does not
  30    however invalidate any other reasons why the executable file might be
  31    covered by the GNU General Public License.  */
  32
  33 #include "list.h"
  34 #ifdef HAVE_SYS_TYPES_H
  35 # include <sys/types.h>
  36 #endif
  37 #include <stdlib.h>
  38
  39 /* Return a cons cell produced from (head . tail) */
  40
  41 LinkedList*
  42 list_cons(void* head, LinkedList* tail)
  43 {
  44   LinkedList* cell;
  45
  46   cell = (LinkedList*)malloc(sizeof(LinkedList));
  47   cell->head = head;
  48   cell->tail = tail;
  49   return cell;
  50 }
  51
  52 /* Return the length of a list, list_length(NULL) returns zero */
  53
  54 int
  55 list_length(LinkedList* list)
  56 {
  57   int i = 0;
  58   while(list)
  59     {
  60       i += 1;
  61       list = list->tail;
  62     }
  63   return i;
  64 }
  65
  66 /* Return the Nth element of LIST, where N count from zero.  If N
  67    larger than the list length, NULL is returned  */
  68
  69 void*
  70 list_nth(int index, LinkedList* list)
  71 {
  72   while(index-- != 0)
  73     {
  74       if(list->tail)
  75         list = list->tail;
  76       else
  77         return 0;
  78     }
  79   return list->head;
  80 }
  81
  82 /* Remove the element at the head by replacing it by its successor */
  83
  84 void
  85 list_remove_head(LinkedList** list)
  86 {
  87   if (!*list) return;
  88   if ((*list)->tail)
  89     {
  90       LinkedList* tail = (*list)->tail; /* fetch next */
  91       *(*list) = *tail;         /* copy next to list head */
  92       free(tail);                       /* free next */
  93     }
  94   else                          /* only one element in list */
  95     {
  96       free(*list);
  97       (*list) = 0;
  98     }
  99 }
 100
 101
 102 /* Remove the element with `car' set to ELEMENT */
 103 /*
 104 void
 105 list_remove_elem(LinkedList** list, void* elem)
 106 {
 107   while (*list)
 108     {
 109       if ((*list)->head == elem)
 110         list_remove_head(list);
 111       *list = (*list ? (*list)->tail : NULL);
 112     }
 113 }*/
 114
 115 LinkedList *
 116 list_remove_elem(LinkedList* list, void* elem)
 117 {
 118     LinkedList *tmp;
 119
 120     if (list) {
 121         if (list->head == elem) {
 122             tmp = list->tail;
 123             free(list);
 124             return tmp;
 125         }
 126         list->tail = list_remove_elem(list->tail, elem);
 127         return list;
 128     }
 129     return NULL;
 130 }
 131
 132
 133 /* Return element that has ELEM as car */
 134
 135 LinkedList*
 136 list_find(LinkedList* list, void* elem)
 137 {
 138   while(list)
 139     {
 140     if (list->head == elem)
 141       return list;
 142     list = list->tail;
 143     }
 144   return NULL;
 145 }
 146
 147 /* Free list (backwards recursive) */
 148
 149 void
 150 list_free(LinkedList* list)
 151 {
 152   if(list)
 153     {
 154       list_free(list->tail);
 155       free(list);
 156     }
 157 }
 158
 159 /* Map FUNCTION over all elements in LIST */
 160
 161 void
 162 list_mapcar(LinkedList* list, void(*function)(void*))
 163 {
 164   while(list)
 165     {
 166       (*function)(list->head);
 167       list = list->tail;
 168     }
 169 }