incubator-nuttx/libs/libc/obstack/lib_obstack_free.c

78 lines
2.9 KiB
C

/****************************************************************************
* libs/libc/obstack/lib_obstack_free.c
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <obstack.h>
#include <nuttx/lib/lib.h>
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: obstack_free
*
* Description:
* Free objects (and everything allocated in the specified obstack more
* recently than object). You can pass NULL to free everything.
* The buffer the allocated object was preset is kept and thus can be
* immediately reused for growing. The only exception for this is when NULL
* is passed as in such case even the last buffer is freed.
*
* Input Parameters:
* h: pointer to the handle object belongs to
* object: the pointer to the object or NULL
*
****************************************************************************/
void obstack_free(FAR struct obstack *h, FAR void *object)
{
FAR struct _obstack_chunk *prev;
while (h->chunk)
{
if (object >=
(FAR void *)((FAR char *)&h->chunk + sizeof(struct _obstack_chunk))
&& object < (FAR void *)h->chunk->limit)
{
/* The object is in this chunk so just move object base.
* Note: this keeps the last chunk allocated. This is desirable
* behavior as we can decide if we want to reuse it by either
* passing NULL to free everything or the first returned object to
* keep the chunk allocated.
*/
h->object_base = object;
h->next_free = object;
return;
}
prev = h->chunk->prev;
lib_free(h->chunk);
h->chunk = prev;
}
h->object_base = NULL;
h->next_free = NULL;
}