added a generic linked list object (files linkedlist.h/c)

1 files changed, 119 insertions, 0 deletions

diff --git a/linkedlist.c b/linkedlist.c
new file mode 100644
index 00000000..d8a98286
--- /dev/null
+++ b/linkedlist.c
@@ -0,0 +1,119 @@
+/* linkedlist.c
+ * This file set implements a generic linked list object. It can be used
+ * wherever a linke list is required.
+ * 
+ * NOTE: we do not currently provide a constructor and destructor for the
+ * object itself as we assume it will always be part of another strucuture.
+ * Having a pointer to it, I think, does not really make sense but costs
+ * performance. Consequently, there is is llInit() and llDestroy() and they
+ * do what a constructor and destructur do, except for creating the
+ * linkedList_t structure itself.
+ *
+ * File begun on 2007-07-31 by RGerhards
+ *
+ * Copyright 2007 Rainer Gerhards and Adiscon GmbH.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+ *
+ * A copy of the GPL can be found in the file "COPYING" in this distribution.
+ */
+#include "config.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <assert.h>
+
+#include "rsyslog.h"
+#include "linkedlist.h"
+
+
+/* Initialize an existing linkedList_t structure
+ */
+rsRetVal llInit(linkedList_t *pThis, rsRetVal (*pEltDestructor)(void*))
+{
+	assert(pThis != NULL);
+	assert(pEltDestructor != NULL);
+
+	pThis->pEltDestruct = pEltDestructor;
+	pThis->cmpOp = NULL;
+	pThis->pKey = NULL;
+	pThis->iNumElts = 0;
+	pThis->pRoot = NULL;
+	pThis->pLast = NULL;
+
+	return RS_RET_OK;
+};
+	
+
+/* llDestroy - destroys a COMPLETE linkedList
+ */
+rsRetVal llDestroy(linkedList_t *pThis)
+{
+	DEFiRet;
+	llElt_t *pElt;
+	llElt_t *pEltPrev;
+
+	assert(pThis != NULL);
+
+	pElt = pThis->pRoot;
+	while(pElt != NULL) {
+		pEltPrev = pElt;
+		pElt = pElt->pNext;
+		/* we ignore errors during destruction, as we need to try
+		 * finish the linked list in any case.
+		 */
+		pThis->pEltDestruct(pEltPrev->pData);
+		free(pEltPrev);
+	}
+
+	return iRet;
+}
+
+
+/* get next user data element of a linked list. The caller must also
+ * provide a "cookie" to the function. On initial call, it must be
+ * NULL. Other than that, the caller is not allowed to to modify the
+ * cookie. In the current implementation, the cookie is an actual
+ * pointer to the current list element, but this is nothing that the
+ * caller should rely on.
+ */
+rsRetVal llGetNextElt(linkedList_t *pThis, linkedListCookie_t *ppElt, void **ppUsr)
+{
+	llElt_t *pElt;
+	DEFiRet;
+
+	assert(pThis != NULL);
+	assert(ppElt != NULL);
+	assert(ppUsr != NULL);
+
+	pElt = *ppElt;
+
+	pElt = (pElt == NULL) ? pThis->pRoot : pElt->pNext;
+
+	if(pElt == NULL) {
+		iRet = RS_RET_END_OF_LINKEDLIST;
+	} else {
+		pElt = pThis->pRoot;
+		*ppUsr = pElt->pData;
+	}
+
+	*ppElt = pElt;
+
+	return iRet;
+}
+
+/*
+ * vi:set ai:
+ */