github.com/Schaudge/grailbase@v0.0.0-20240223061707-44c758a471c0/compress/libdeflate/aligned_malloc.c (about)

     1  /*
     2   * aligned_malloc.c - aligned memory allocation
     3   *
     4   * Originally public domain; changes after 2016-09-07 are copyrighted.
     5   *
     6   * Copyright 2016 Eric Biggers
     7   *
     8   * Permission is hereby granted, free of charge, to any person
     9   * obtaining a copy of this software and associated documentation
    10   * files (the "Software"), to deal in the Software without
    11   * restriction, including without limitation the rights to use,
    12   * copy, modify, merge, publish, distribute, sublicense, and/or sell
    13   * copies of the Software, and to permit persons to whom the
    14   * Software is furnished to do so, subject to the following
    15   * conditions:
    16   *
    17   * The above copyright notice and this permission notice shall be
    18   * included in all copies or substantial portions of the Software.
    19   *
    20   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
    21   * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
    22   * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
    23   * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
    24   * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
    25   * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
    26   * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
    27   * OTHER DEALINGS IN THE SOFTWARE.
    28   */
    29  
    30  /*
    31   * This file provides portable aligned memory allocation functions that only
    32   * use malloc() and free().  This avoids portability problems with
    33   * posix_memalign(), aligned_alloc(), etc.
    34   */
    35  
    36  #include <stdlib.h>
    37  
    38  #include "aligned_malloc.h"
    39  
    40  void *
    41  aligned_malloc(size_t alignment, size_t size)
    42  {
    43  	void *ptr = malloc(sizeof(void *) + alignment - 1 + size);
    44  	if (ptr) {
    45  		void *orig_ptr = ptr;
    46  		ptr = (void *)ALIGN((uintptr_t)ptr + sizeof(void *), alignment);
    47  		((void **)ptr)[-1] = orig_ptr;
    48  	}
    49  	return ptr;
    50  }
    51  
    52  void
    53  aligned_free(void *ptr)
    54  {
    55  	if (ptr)
    56  		free(((void **)ptr)[-1]);
    57  }