4781379ee2
Using void* for arithmetics is a GCC extension, and thus should not be used for portable code.
99 lines
3.6 KiB
C
99 lines
3.6 KiB
C
/****************************************************************************
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* libs/libc/obstack/lib_obstack_finish.c
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <obstack.h>
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#include <assert.h>
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#include "lib_obstack_malloc.h"
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: obstack_finish
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*
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* Description:
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* Finish growing object and receive address to it.
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* Compared to the GlibC version this uses realloc to reduce buffer size to
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* only allocated amount. The non-standard obstack_finish_norealloc can be
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* used if you want the standard behavior for ever reason.
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*
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* Input Parameters:
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* h: pointer to the handle used to grow the object.
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*
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* Returned Value:
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* Permanent address to the object.
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*
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****************************************************************************/
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FAR void *obstack_finish(FAR struct obstack *h)
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{
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size_t chsize;
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void *chbase;
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/* To reduce memory used by allocation we reallocate the chunk to fit
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* exactly data it contains.
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* This can be performed only if there is no other object preset in the
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* chunk already as we can't ensure that realloc won't move the data and
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* thus invalidate already returned address to the existing object.
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* The object can be there if called uses obstack_finish alongside with
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* obstack_finish_norealloc.
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*/
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chbase = (FAR char *)h->chunk + sizeof(struct _obstack_chunk);
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if (chbase == h->object_base)
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{
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chsize = h->next_free - (FAR char *)h->chunk;
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h->chunk = lib_obstack_realloc(h->chunk, chsize);
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h->chunk->limit = (FAR char *)h->chunk + chsize;
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h->object_base = h->chunk->limit;
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h->next_free = h->chunk->limit;
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return (FAR char *)h->chunk + sizeof(struct _obstack_chunk);
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}
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return obstack_finish_norealloc(h);
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}
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/****************************************************************************
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* Name: obstack_finish_norealloc
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*
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* Description:
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* Finish growing object and receive address to it without reallocating
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* buffer to fit the object (keeping space for more growth).
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*
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* Input Parameters:
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* h: pointer to the handle used to grow the object.
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*
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* Returned Value:
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* Permanent address to the object.
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*
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****************************************************************************/
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FAR void *obstack_finish_norealloc(FAR struct obstack *h)
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{
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FAR char *res = h->object_base;
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h->object_base = h->next_free;
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return res;
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}
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