--- /dev/null
+/* ========================================================================== **
+ * ubi_sLinkList.c
+ *
+ * Copyright (C) 1997, 1998 by Christopher R. Hertel
+ *
+ * Email: crh@ubiqx.mn.org
+ * -------------------------------------------------------------------------- **
+ * This module implements a simple singly-linked list.
+ * -------------------------------------------------------------------------- **
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the Free
+ * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ * -------------------------------------------------------------------------- **
+ *
+ * Log: ubi_sLinkList.c,v
+ * Revision 0.10 1999/06/19 16:58:06 crh
+ * Renamed the ubi_slRemove() function in ubi_sLinkList to
+ * ubi_slRemoveNext(). I was bothered by the fact that it didn't
+ * match the functionality of the ubi_dlRemove() function in
+ * ubi_dLinkList. The new name is more 'correct'.
+ *
+ * Revision 0.9 1998/07/24 07:30:20 crh
+ * Added the ubi_slNewList() macro.
+ *
+ * Revision 0.8 1998/06/04 21:29:27 crh
+ * Upper-cased defined constants (eg UBI_BINTREE_H) in some header files.
+ * This is more "standard", and is what people expect. Weird, eh?
+ *
+ * Revision 0.7 1998/06/03 18:06:03 crh
+ * Further fiddling with sys_include.h, which has been moved from the .c file
+ * to the .h file.
+ *
+ * Revision 0.6 1998/06/02 01:38:47 crh
+ * Changed include file name from ubi_null.h to sys_include.h to make it
+ * more generic.
+ *
+ * Revision 0.5 1998/05/20 04:38:05 crh
+ * The C file now includes ubi_null.h. See ubi_null.h for more info.
+ *
+ * Revision 0.4 1998/03/10 02:23:20 crh
+ * Combined ubi_StackQueue and ubi_sLinkList into one module. Redesigned
+ * the functions and macros. Not a complete rewrite but close to it.
+ *
+ * Revision 0.3 1998/01/03 01:59:52 crh
+ * Added ubi_slCount() macro.
+ *
+ * Revision 0.2 1997/10/21 03:35:18 crh
+ * Added parameter <After> in function Insert(). Made necessary changes
+ * to macro AddHead() and added macro AddHere().
+ *
+ * Revision 0.1 1997/10/16 02:53:45 crh
+ * Initial Revision.
+ *
+ * -------------------------------------------------------------------------- **
+ * This module implements a singly-linked list which may also be used as a
+ * queue or a stack. For a queue, entries are added at the tail and removed
+ * from the head of the list. For a stack, the entries are entered and
+ * removed from the head of the list. A traversal of the list will always
+ * start at the head of the list and proceed toward the tail. This is all
+ * mind-numbingly simple, but I'm surprised by the number of programs out
+ * there which re-implement this a dozen or so times.
+ *
+ * Note: When the list header is initialized, the Tail pointer is set to
+ * point to the Head pointer. This simplifies things a great deal,
+ * except that you can't initialize a stack or queue by simply
+ * zeroing it out. One sure way to initialize the header is to call
+ * ubi_slInit(). Another option would be something like this:
+ *
+ * ubi_slNewList( MyList );
+ *
+ * Which translates to:
+ *
+ * ubi_slList MyList[1] = { NULL, (ubi_slNodePtr)MyList, 0 };
+ *
+ * See ubi_slInit(), ubi_slNewList(), and the ubi_slList structure
+ * for more info.
+ *
+ * + Also, note that this module is similar to the ubi_dLinkList
+ * module. There are three key differences:
+ * - This is a singly-linked list, the other is a doubly-linked
+ * list.
+ * - In this module, if the list is empty, the tail pointer will
+ * point back to the head of the list as described above. This
+ * is not done in ubi_dLinkList.
+ * - The ubi_slRemoveNext() function, by necessity, removes the
+ * 'next' node. In ubi_dLinkList, the ubi_dlRemove() function
+ * removes the 'current' node.
+ *
+ * ========================================================================== **
+ */
+
+#include "ubi_sLinkList.h" /* Header for *this* module. */
+
+/* ========================================================================== **
+ * Functions...
+ */
+
+ubi_slListPtr ubi_slInitList( ubi_slListPtr ListPtr )
+ /* ------------------------------------------------------------------------ **
+ * Initialize a singly-linked list header.
+ *
+ * Input: ListPtr - A pointer to the list structure that is to be
+ * initialized for use.
+ *
+ * Output: A pointer to the initialized list header (i.e., same as
+ * <ListPtr>).
+ *
+ * ------------------------------------------------------------------------ **
+ */
+ {
+ ListPtr->Head = NULL;
+ ListPtr->Tail = (ubi_slNodePtr)ListPtr;
+ ListPtr->count = 0;
+ return( ListPtr );
+ } /* ubi_slInitList */
+
+ubi_slNodePtr ubi_slInsert( ubi_slListPtr ListPtr,
+ ubi_slNodePtr New,
+ ubi_slNodePtr After )
+ /* ------------------------------------------------------------------------ **
+ * Add a node to the list.
+ *
+ * Input: ListPtr - A pointer to the list into which the node is to
+ * be inserted.
+ * New - Pointer to the node that is to be added to the list.
+ * After - Pointer to a list in a node after which the new node
+ * will be inserted. If NULL, then the new node will
+ * be added at the head of the list.
+ *
+ * Output: A pointer to the node that was inserted into the list (i.e.,
+ * the same as <New>).
+ *
+ * ------------------------------------------------------------------------ **
+ */
+ {
+ After = After ? After : (ubi_slNodePtr)ListPtr;
+ New->Next = After->Next;
+ After->Next = New;
+ if( !(New->Next) )
+ ListPtr->Tail = New;
+ (ListPtr->count)++;
+ return( New );
+ } /* ubi_slInsert */
+
+ubi_slNodePtr ubi_slRemoveNext( ubi_slListPtr ListPtr, ubi_slNodePtr AfterMe )
+ /* ------------------------------------------------------------------------ **
+ * Remove the node followng <AfterMe>. If <AfterMe> is NULL, remove from
+ * the head of the list.
+ *
+ * Input: ListPtr - A pointer to the list from which the node is to be
+ * removed.
+ * AfterMe - Pointer to the node preceeding the node to be
+ * removed.
+ *
+ * Output: A pointer to the node that was removed, or NULL if the list is
+ * empty.
+ *
+ * ------------------------------------------------------------------------ **
+ */
+ {
+ ubi_slNodePtr DelNode;
+
+ AfterMe = AfterMe ? AfterMe : (ubi_slNodePtr)ListPtr;
+ DelNode = AfterMe->Next;
+ if( DelNode )
+ {
+ if( !(DelNode->Next) )
+ ListPtr->Tail = AfterMe;
+ AfterMe->Next = DelNode->Next;
+ (ListPtr->count)--;
+ }
+ return( DelNode );
+ } /* ubi_slRemoveNext */
+
+/* ================================ The End ================================= */
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