259 lines
6.6 KiB
C
259 lines
6.6 KiB
C
/**
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* \file
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* <!--
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* This file is part of BeRTOS.
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*
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* Bertos is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*
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* As a special exception, you may use this file as part of a free software
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* library without restriction. Specifically, if other files instantiate
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* templates or use macros or inline functions from this file, or you compile
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* this file and link it with other files to produce an executable, this
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* file does not by itself cause the resulting executable to be covered by
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* the GNU General Public License. This exception does not however
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* invalidate any other reasons why the executable file might be covered by
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* the GNU General Public License.
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*
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* Copyright 2004 Develer S.r.l. (http://www.develer.com/)
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* Copyright 1999, 2000, 2001, 2008 Bernie Innocenti <bernie@codewiz.org>
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* -->
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*
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* \brief Heap subsystem (public interface).
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*
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* \author Bernie Innocenti <bernie@codewiz.org>
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*/
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#include "heap.h"
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#include <cfg/debug.h> // ASSERT()
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#include <string.h> // memset()
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#define FREE_FILL_CODE 0xDEAD
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#define ALLOC_FILL_CODE 0xBEEF
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/*
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* This function prototype is deprecated, will change in:
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* void heap_init(struct Heap* h, heap_buf_t* memory, size_t size)
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* in the next BeRTOS release.
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*/
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void heap_init(struct Heap* h, void* memory, size_t size)
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{
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#ifdef _DEBUG
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memset(memory, FREE_FILL_CODE, size);
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#endif
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ASSERT2(((size_t)memory % alignof(heap_buf_t)) == 0,
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"memory buffer is unaligned, please use the HEAP_DEFINE_BUF() macro to declare heap buffers!\n");
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/* Initialize heap with a single big chunk */
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h->FreeList = (MemChunk *)memory;
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h->FreeList->next = NULL;
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h->FreeList->size = size;
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}
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void *heap_allocmem(struct Heap* h, size_t size)
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{
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MemChunk *chunk, *prev;
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/* Round size up to the allocation granularity */
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size = ROUND_UP2(size, sizeof(MemChunk));
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/* Handle allocations of 0 bytes */
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if (!size)
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size = sizeof(MemChunk);
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/* Walk on the free list looking for any chunk big enough to
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* fit the requested block size.
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*/
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for (prev = (MemChunk *)&h->FreeList, chunk = h->FreeList;
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chunk;
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prev = chunk, chunk = chunk->next)
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{
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if (chunk->size >= size)
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{
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if (chunk->size == size)
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{
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/* Just remove this chunk from the free list */
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prev->next = chunk->next;
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#ifdef _DEBUG
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memset(chunk, ALLOC_FILL_CODE, size);
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#endif
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return (void *)chunk;
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}
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else
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{
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/* Allocate from the END of an existing chunk */
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chunk->size -= size;
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#ifdef _DEBUG
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memset((uint8_t *)chunk + chunk->size, ALLOC_FILL_CODE, size);
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#endif
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return (void *)((uint8_t *)chunk + chunk->size);
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}
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}
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}
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return NULL; /* fail */
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}
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void heap_freemem(struct Heap* h, void *mem, size_t size)
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{
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MemChunk *prev;
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ASSERT(mem);
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#ifdef _DEBUG
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memset(mem, FREE_FILL_CODE, size);
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#endif
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/* Round size up to the allocation granularity */
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size = ROUND_UP2(size, sizeof(MemChunk));
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/* Handle allocations of 0 bytes */
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if (!size)
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size = sizeof(MemChunk);
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/* Special cases: first chunk in the free list or memory completely full */
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ASSERT((uint8_t*)mem != (uint8_t*)h->FreeList);
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if (((uint8_t *)mem) < ((uint8_t *)h->FreeList) || !h->FreeList)
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{
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/* Insert memory block before the current free list head */
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prev = (MemChunk *)mem;
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prev->next = h->FreeList;
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prev->size = size;
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h->FreeList = prev;
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}
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else /* Normal case: not the first chunk in the free list */
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{
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/*
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* Walk on the free list. Stop at the insertion point (when mem
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* is between prev and prev->next)
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*/
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prev = h->FreeList;
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while (prev->next < (MemChunk *)mem && prev->next)
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prev = prev->next;
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/* Make sure mem is not *within* prev */
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ASSERT((uint8_t*)mem >= (uint8_t*)prev + prev->size);
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/* Should it be merged with previous block? */
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if (((uint8_t *)prev) + prev->size == ((uint8_t *)mem))
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{
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/* Yes */
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prev->size += size;
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}
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else /* not merged with previous chunk */
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{
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MemChunk *curr = (MemChunk*)mem;
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/* insert it after the previous node
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* and move the 'prev' pointer forward
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* for the following operations
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*/
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curr->next = prev->next;
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curr->size = size;
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prev->next = curr;
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/* Adjust for the following test */
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prev = curr;
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}
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}
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/* Also merge with next chunk? */
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if (((uint8_t *)prev) + prev->size == ((uint8_t *)prev->next))
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{
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prev->size += prev->next->size;
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prev->next = prev->next->next;
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/* There should be only one merge opportunity, becuase we always merge on free */
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ASSERT((uint8_t*)prev + prev->size != (uint8_t*)prev->next);
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}
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}
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/**
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* Returns the number of free bytes in a heap.
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* \param h the heap to check.
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*
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* \note The returned value is the sum of all free memory regions
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* in the heap.
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* Those regions are likely to be *not* contiguous,
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* so a successive allocation may fail even if the
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* requested amount of memory is lower than the current free space.
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*/
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size_t heap_freeSpace(struct Heap *h)
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{
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size_t free_mem = 0;
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for (MemChunk *chunk = h->FreeList; chunk; chunk = chunk->next)
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free_mem += chunk->size;
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return free_mem;
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}
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#if CONFIG_HEAP_MALLOC
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/**
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* Standard malloc interface
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*/
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void *heap_malloc(struct Heap* h, size_t size)
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{
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size_t *mem;
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size += sizeof(size_t);
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if ((mem = (size_t*)heap_allocmem(h, size)))
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*mem++ = size;
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return mem;
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}
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/**
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* Standard calloc interface
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*/
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void *heap_calloc(struct Heap* h, size_t size)
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{
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void *mem;
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if ((mem = heap_malloc(h, size)))
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memset(mem, 0, size);
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return mem;
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}
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/**
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* Free a block of memory, determining its size automatically.
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*
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* \param h Heap from which the block was allocated.
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* \param mem Pointer to a block of memory previously allocated with
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* either heap_malloc() or heap_calloc().
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*
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* \note If \a mem is a NULL pointer, no operation is performed.
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*
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* \note Freeing the same memory block twice has undefined behavior.
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*
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* \note This function works like the ANSI C free().
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*/
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void heap_free(struct Heap *h, void *mem)
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{
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size_t *_mem = (size_t *)mem;
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if (_mem)
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{
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--_mem;
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heap_freemem(h, _mem, *_mem);
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}
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}
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#endif /* CONFIG_HEAP_MALLOC */
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