104 lines
3.7 KiB
C
104 lines
3.7 KiB
C
/****************************************************************************
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* mm/umm_heap/umm_realloc.c
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*
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* Copyright (C) 2007, 2009, 2013-2015 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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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 <nuttx/config.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <nuttx/mm/mm.h>
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#include "umm_heap/umm_heap.h"
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: realloc
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*
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* Description:
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* Re-allocate memory in the user heap.
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*
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* Input Parameters:
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* oldmem - The old memory allocated
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* newsize - Size (in bytes) of the new memory region to be re-allocated.
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*
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* Returned Value:
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* The address of the re-allocated memory (NULL on failure to re-allocate)
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*
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****************************************************************************/
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FAR void *realloc(FAR void *oldmem, size_t size)
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{
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#if defined(CONFIG_ARCH_ADDRENV) && defined(CONFIG_BUILD_KERNEL)
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FAR void *brkaddr;
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FAR void *mem;
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/* Loop until we successfully allocate the memory or until an error
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* occurs. If we fail to allocate memory on the first pass, then call
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* sbrk to extend the heap by one page. This may require several
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* passes if more the size of the allocation is more than one page.
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*
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* An alternative would be to increase the size of the heap by the
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* full requested allocation in sbrk(). Then the loop should never
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* execute more than twice (but more memory than we need may be
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* allocated).
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*/
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do
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{
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mem = mm_realloc(USR_HEAP, oldmem, size);
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if (!mem)
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{
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brkaddr = sbrk(size);
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if (brkaddr == (FAR void *)-1)
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{
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return NULL;
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}
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}
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}
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while (mem == NULL);
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return mem;
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#else
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return mm_realloc(USR_HEAP, oldmem, size);
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#endif
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}
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