I hereby relicense all my work on Sortix under the ISC license as below. All Sortix contributions by other people are already under this license, are not substantial enough to be copyrightable, or have been removed. All imported code from other projects is compatible with this license. All GPL licensed code from other projects had previously been removed. Copyright 2011-2016 Jonas 'Sortie' Termansen and contributors. Permission to use, copy, modify, and distribute this software for any purpose with or without fee is hereby granted, provided that the above copyright notice and this permission notice appear in all copies. THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
145 lines
4.3 KiB
C
145 lines
4.3 KiB
C
/*
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* Copyright (c) 2011, 2012, 2013, 2014, 2015 Jonas 'Sortie' Termansen.
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*
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* stdlib/realloc.c
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* Reallocates a chunk of memory from the dynamic memory heap.
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*/
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#include <assert.h>
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#include <errno.h>
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#include <malloc.h>
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#include <stdlib.h>
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#include <string.h>
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#if defined(HEAP_NO_ASSERT)
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#define __heap_verify() ((void) 0)
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#undef assert
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#define assert(x) do { ((void) 0); } while ( 0 )
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#endif
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#if !defined(HEAP_GUARD_DEBUG)
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void* realloc(void* ptr, size_t requested_size)
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{
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if ( !ptr )
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return malloc(requested_size);
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if ( !heap_size_has_bin(requested_size) )
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return errno = ENOMEM, (void*) NULL;
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// Decide how big an allocation we would like to make.
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size_t requested_chunk_outer_size = sizeof(struct heap_chunk) +
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sizeof(struct heap_chunk_post);
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size_t requested_chunk_inner_size = heap_align(requested_size);
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size_t requested_chunk_size = requested_chunk_outer_size +
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requested_chunk_inner_size;
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if ( !heap_size_has_bin(requested_chunk_size) )
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return errno = ENOMEM, (void*) NULL;
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__heap_lock();
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__heap_verify();
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// Retrieve the chunk that contains this allocation.
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struct heap_chunk* chunk = heap_data_to_chunk((uint8_t*) ptr);
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assert(chunk->chunk_magic == HEAP_CHUNK_MAGIC);
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assert(heap_chunk_to_post(chunk)->chunk_magic == HEAP_CHUNK_MAGIC);
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assert(heap_chunk_to_post(chunk)->chunk_size == chunk->chunk_size);
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// Do nothing if the chunk already has the ideal size.
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if ( chunk->chunk_size == requested_chunk_size )
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{
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__heap_verify();
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__heap_unlock();
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return heap_chunk_to_data(chunk);
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}
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// If the ideal size is smaller than the current, attempt the shrink the
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// allocation if a new chunk can be created.
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if ( requested_chunk_size < chunk->chunk_size )
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{
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assert(requested_chunk_size <= chunk->chunk_size);
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if ( heap_can_split_chunk(chunk, requested_chunk_size) )
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heap_split_chunk(chunk, requested_chunk_size);
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__heap_verify();
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__heap_unlock();
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return heap_chunk_to_data(chunk);
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}
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// TODO: What if the right neighbor is the part edge?
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// If we need to expand the chunk, attempt to combine it with its right
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// neighbor if it is large enough.
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struct heap_chunk* right;
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if ( (right = heap_chunk_right(chunk)) &&
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!heap_chunk_is_used(right) &&
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requested_chunk_size <= chunk->chunk_size + right->chunk_size )
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{
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heap_remove_chunk(right);
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heap_chunk_format((uint8_t*) chunk, chunk->chunk_size + right->chunk_size);
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assert(requested_chunk_size <= chunk->chunk_size);
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if ( heap_can_split_chunk(chunk, requested_chunk_size) )
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heap_split_chunk(chunk, requested_chunk_size);
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__heap_verify();
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__heap_unlock();
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return heap_chunk_to_data(chunk);
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}
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// It appears that we cannot retain the orignal allocation location and we
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// will have to relocate the allocation elsewhere to expand it.
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size_t orignal_ptr_size = heap_chunk_data_size(chunk);
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__heap_verify();
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__heap_unlock();
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assert(orignal_ptr_size < requested_size);
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void* result = malloc(requested_size);
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if ( !result )
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return (void*) NULL;
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memcpy(result, ptr, orignal_ptr_size);
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free(ptr);
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return result;
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}
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#else
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void* realloc(void* ptr, size_t requested_size)
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{
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if ( !ptr )
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return malloc(requested_size);
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struct heap_alloc* alloc_ptr =
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(struct heap_alloc*) HEAP_ALIGN_PAGEDOWN((uintptr_t) ptr - 16);
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assert(alloc_ptr->from == (uintptr_t) alloc_ptr);
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struct heap_alloc alloc = *alloc_ptr;
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size_t size = (alloc.from + alloc.size - HEAP_PAGE_SIZE) - (uintptr_t) ptr;
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if ( requested_size <= size )
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return ptr;
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void* replacement = malloc(requested_size);
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if ( !replacement )
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return NULL;
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memcpy(replacement, ptr, size);
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free(ptr);
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return replacement;
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}
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#endif
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