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

71 lines
2.6 KiB
C

/****************************************************************************
* libs/libc/obstack/lib_obstack_alloc.c
*
* SPDX-License-Identifier: Apache-2.0
*
* 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 "lib_obstack_malloc.h"
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: obstack_alloc
*
* Description:
* Allocate an object of given size with uninitialized bytes.
* Compared to the GlibC version this uses malloc to allocate exactly
* required space (plus overhead) and nothing more.
*
* Input Parameters:
* h: pointer to the handle to allocate an object in
* size: number of bytes to allocate
*
****************************************************************************/
FAR void *obstack_alloc(FAR struct obstack *h, size_t size)
{
FAR struct _obstack_chunk *prev;
FAR void *res;
if (h->chunk == NULL || (h->chunk->limit - h->object_base) < size)
{
/* TODO: could we just expand current allocation? */
prev = h->chunk;
h->chunk = lib_obstack_malloc(size + sizeof(struct _obstack_chunk));
h->chunk->limit =
(FAR char *)h->chunk + sizeof(struct _obstack_chunk) + size;
h->chunk->prev = prev;
h->object_base = (FAR char *)h->chunk + sizeof(struct _obstack_chunk);
}
res = h->object_base;
h->object_base += size;
h->next_free = h->object_base;
return res;
}