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/**************************************************************************
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* Copyright 2008-2010 VMware, Inc.
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the
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* "Software"), to deal in the Software without restriction, including
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* without limitation the rights to use, copy, modify, merge, publish,
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* distribute, sub license, and/or sell copies of the Software, and to
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* permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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* The above copyright notice and this permission notice (including the
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* next paragraph) shall be included in all copies or substantial portions
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
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* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
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* IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
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* ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
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* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
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* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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**************************************************************************/
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* Memory alignment wrappers.
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#error "Must not be included directly. Include os_memory.h instead"
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* Add two size_t values with integer overflow check.
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* TODO: leverage __builtin_add_overflow where available
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add_overflow_size_t(size_t a, size_t b, size_t *res)
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return *res < a || *res < b;
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#if defined(HAVE_POSIX_MEMALIGN)
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os_malloc_aligned(size_t size, size_t alignment)
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alignment = (alignment + sizeof(void*) - 1) & ~(sizeof(void*) - 1);
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if(posix_memalign(&ptr, alignment, size) != 0)
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#define os_free_aligned(_ptr) free(_ptr)
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* Return memory on given byte alignment
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os_malloc_aligned(size_t size, size_t alignment)
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* alloc_size = size + alignment + sizeof(void *)
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* while checking for overflow.
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if (add_overflow_size_t(size, alignment, &alloc_size) ||
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add_overflow_size_t(alloc_size, sizeof(void *), &alloc_size)) {
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ptr = (char *) os_malloc(alloc_size);
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buf = (char *)(((uintptr_t)ptr + sizeof(void *) + alignment - 1) & ~((uintptr_t)(alignment - 1)));
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*(char **)(buf - sizeof(void *)) = ptr;
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* Free memory returned by os_malloc_aligned().
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os_free_aligned(void *ptr)
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void **cubbyHole = (void **) ((char *) ptr - sizeof(void *));
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void *realAddr = *cubbyHole;
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* Reallocate memeory, with alignment
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os_realloc_aligned(void *ptr, size_t oldsize, size_t newsize, size_t alignment)
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const size_t copySize = MIN2(oldsize, newsize);
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void *newBuf = os_malloc_aligned(newsize, alignment);
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if (newBuf && ptr && copySize > 0) {
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memcpy(newBuf, ptr, copySize);
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os_free_aligned(ptr);