List_Insert.c
1.67 KB
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/*
* List_Insert.c --
*
* Source code for the List_Insert library procedure.
*
* Copyright 1988 Regents of the University of California
* Permission to use, copy, modify, and distribute this
* software and its documentation for any purpose and without
* fee is hereby granted, provided that the above copyright
* notice appear in all copies. The University of California
* makes no representations about the suitability of this
* software for any purpose. It is provided "as is" without
* express or implied warranty.
*/
#include <stdio.h>
#include "list.h"
/*
* ----------------------------------------------------------------------------
*
* List_Insert --
*
* Insert the list element pointed to by itemPtr into a List after
* destPtr. Perform a primitive test for self-looping by returning
* failure if the list element is being inserted next to itself.
*
* Results:
* None.
*
* Side effects:
* The list containing destPtr is modified to contain itemPtr.
*
* ----------------------------------------------------------------------------
*/
void
List_Insert(register List_Links* itemPtr, /* structure to insert */
register List_Links* destPtr/* structure after which to insert it */)
{
if (itemPtr == (List_Links *) NIL || destPtr == (List_Links *) NIL
|| !itemPtr || !destPtr) {
List_Error("List_Insert: itemPtr (%llx) or destPtr (%llx) is NIL.\n",
itemPtr, destPtr);
return;
}
if (itemPtr == destPtr) {
List_Error("List_Insert: trying to insert something after itself.\n");
return;
}
itemPtr->nextPtr = destPtr->nextPtr;
itemPtr->prevPtr = destPtr;
destPtr->nextPtr->prevPtr = itemPtr;
destPtr->nextPtr = itemPtr;
}