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Implemented realloc().

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git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@28454 a95241bf-73f2-0310-859d-f6bbb57e9c96
This commit is contained in:
Ingo Weinhold 2008-11-02 02:59:15 +00:00
parent 2ef4a8b524
commit f68fa9d364
1 changed files with 29 additions and 8 deletions
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37
src/system/runtime_loader/heap.cpp
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@ -24,7 +24,7 @@ static const size_t kInitialHeapSize = 65536;
* linked list). * linked list).
* When memory is allocated, the smallest free chunk that contains * When memory is allocated, the smallest free chunk that contains
* the requested size is split (or taken as a whole if it can't be * the requested size is split (or taken as a whole if it can't be
* splitted anymore), and it's lower half will be removed from the * splitted anymore), and it's lower half will be removed from the
* free list. * free list.
* The free list is ordered by size, starting with the smallest * The free list is ordered by size, starting with the smallest
* free chunk available. When a chunk is freed, it will be joint * free chunk available. When a chunk is freed, it will be joint
@ -120,7 +120,7 @@ free_chunk::Join(free_chunk *chunk)
} }
void void
free_chunk::Remove(free_chunk *previous) free_chunk::Remove(free_chunk *previous)
{ {
if (previous == NULL) { if (previous == NULL) {
@ -143,7 +143,7 @@ free_chunk::Remove(free_chunk *previous)
} }
void void
free_chunk::Enqueue() free_chunk::Enqueue()
{ {
free_chunk *chunk = sFreeAnchor.next, *last = &sFreeAnchor; free_chunk *chunk = sFreeAnchor.next, *last = &sFreeAnchor;
@ -237,10 +237,31 @@ dump_chunks(void)
void * void *
realloc(void *buffer, size_t newSize) realloc(void *allocation, size_t newSize)
{ {
// not implemented // free, if new size is 0
return NULL; if (newSize == 0) {
free(allocation);
return NULL;
}
// just malloc(), if no previous allocation
if (allocation == NULL)
return malloc(newSize);
// we're lazy and don't shrink allocations
free_chunk* chunk = free_chunk::SetToAllocated(allocation);
if (chunk->Size() >= newSize)
return allocation;
// the allocation needs to grow -- allocate a new one and memcpy()
void* newAllocation = malloc(newSize);
if (newAllocation != NULL) {
memcpy(newAllocation, allocation, chunk->Size());
free(allocation);
}
return newAllocation;
} }
@ -322,7 +343,7 @@ free(void *allocated)
// remove the joined chunk from the list // remove the joined chunk from the list
last->next = freedChunk->next; last->next = freedChunk->next;
chunk = last; chunk = last;
if (++joinCount == 2) if (++joinCount == 2)
break; break;
} }
@ -331,7 +352,7 @@ free(void *allocated)
chunk = chunk->next; chunk = chunk->next;
} }
// enqueue the link at the right position; the // enqueue the link at the right position; the
// free link queue is ordered by size // free link queue is ordered by size
freedChunk->Enqueue(); freedChunk->Enqueue();