reactos/boot/freeldr/freeldr/rtl/list.c

   1 /*
   2  *  FreeLoader
   3  *  Copyright (C) 1998-2003  Brian Palmer  <brianp@sginet.com>
   4  *
   5  *  This program is free software; you can redistribute it and/or modify
   6  *  it under the terms of the GNU General Public License as published by
   7  *  the Free Software Foundation; either version 2 of the License, or
   8  *  (at your option) any later version.
   9  *
  10  *  This program is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  *  GNU General Public License for more details.
  14  *
  15  *  You should have received a copy of the GNU General Public License
  16  *  along with this program; if not, write to the Free Software
  17  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  18  */
  19
  20 #include <freeldr.h>
  21
  22 VOID RtlListInitializeHead(PLIST_ITEM ListHead)
  23 {
  24         ListHead->ListPrev = NULL;
  25         ListHead->ListNext = NULL;
  26 }
  27
  28 VOID RtlListInsertHead(PLIST_ITEM ListHead, PLIST_ITEM Entry)
  29 {
  30         ListHead = RtlListGetHead(ListHead);
  31         ListHead->ListPrev = Entry;
  32         Entry->ListNext = ListHead;
  33         Entry->ListPrev = NULL;
  34 }
  35
  36 VOID RtlListInsertTail(PLIST_ITEM ListHead, PLIST_ITEM Entry)
  37 {
  38         ListHead = RtlListGetTail(ListHead);
  39         ListHead->ListNext = Entry;
  40         Entry->ListNext = NULL;
  41         Entry->ListPrev = ListHead;
  42 }
  43
  44 PLIST_ITEM RtlListRemoveHead(PLIST_ITEM ListHead)
  45 {
  46         PLIST_ITEM OldListHead = RtlListGetHead(ListHead);
  47
  48         ListHead = ListHead->ListNext;
  49         ListHead->ListPrev = NULL;
  50
  51         return OldListHead;
  52 }
  53
  54 PLIST_ITEM RtlListRemoveTail(PLIST_ITEM ListHead)
  55 {
  56         PLIST_ITEM ListTail;
  57
  58         ListTail = RtlListGetTail(ListHead);
  59         ListHead = ListTail->ListPrev;
  60         ListHead->ListNext = NULL;
  61
  62         return ListTail;
  63 }
  64
  65 PLIST_ITEM RtlListGetHead(PLIST_ITEM ListHead)
  66 {
  67         while (ListHead->ListPrev != NULL)
  68         {
  69                 ListHead = ListHead->ListPrev;
  70         }
  71
  72         return ListHead;
  73 }
  74
  75 PLIST_ITEM RtlListGetTail(PLIST_ITEM ListHead)
  76 {
  77         while (ListHead->ListNext != NULL)
  78         {
  79                 ListHead = ListHead->ListNext;
  80         }
  81
  82         return ListHead;
  83 }
  84
  85 BOOL RtlListIsEmpty(PLIST_ITEM ListHead)
  86 {
  87         if (ListHead == NULL)
  88         {
  89                 return TRUE;
  90         }
  91
  92         return (ListHead->ListNext == NULL);
  93 }
  94
  95 ULONG RtlListCountEntries(PLIST_ITEM ListHead)
  96 {
  97         ULONG           Count = 0;
  98
  99         while (ListHead != NULL)
 100         {
 101                 Count++;
 102                 ListHead = ListHead->ListNext;
 103         }
 104
 105         return Count;
 106 }
 107
 108 PLIST_ITEM RtlListGetPrevious(PLIST_ITEM ListEntry)
 109 {
 110         return ListEntry->ListPrev;
 111 }
 112
 113 PLIST_ITEM RtlListGetNext(PLIST_ITEM ListEntry)
 114 {
 115         return ListEntry->ListNext;
 116 }
 117
 118 PLIST_ITEM RtlListRemoveEntry(PLIST_ITEM ListEntry)
 119 {
 120         PLIST_ITEM      ListNext = RtlListGetNext(ListEntry);
 121         PLIST_ITEM      ListPrev = RtlListGetPrevious(ListEntry);
 122
 123         if (ListPrev != NULL)
 124         {
 125                 ListPrev->ListNext = ListNext;
 126         }
 127
 128         if (ListNext != NULL)
 129         {
 130                 ListNext->ListPrev = ListPrev;
 131         }
 132
 133         return ListNext;
 134 }
 135
 136 VOID RtlListInsertEntry(PLIST_ITEM InsertAfter, PLIST_ITEM ListEntry)
 137 {
 138         PLIST_ITEM      ListNext = RtlListGetNext(InsertAfter);
 139
 140         InsertAfter->ListNext = ListEntry;
 141         ListEntry->ListPrev = InsertAfter;
 142         ListEntry->ListNext = ListNext;
 143 }
 144
 145 VOID RtlListMoveEntryPrevious(PLIST_ITEM ListEntry)
 146 {
 147         PLIST_ITEM      ListPrev = RtlListGetPrevious(ListEntry);
 148
 149         if (ListPrev == NULL)
 150         {
 151                 return;
 152         }
 153
 154         //
 155         // Move the previous entry after this one
 156         //
 157         RtlListRemoveEntry(ListPrev);
 158         RtlListInsertEntry(ListEntry, ListPrev);
 159 }
 160
 161 VOID RtlListMoveEntryNext(PLIST_ITEM ListEntry)
 162 {
 163         PLIST_ITEM      ListNext = RtlListGetNext(ListEntry);
 164
 165         if (ListNext == NULL)
 166         {
 167                 return;
 168         }
 169
 170         //
 171         // Move this entry after the next entry
 172         //
 173         RtlListRemoveEntry(ListEntry);
 174         RtlListInsertEntry(ListNext, ListEntry);
 175 }