cosmopolitan/libc/mem/realloc_in_place.c

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│ vi: set et ft=c ts=2 sts=2 sw=2 fenc=utf-8                               :vi │
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2023 Justine Alexandra Roberts Tunney                              │
│                                                                              │
│ Permission to use, copy, modify, and/or 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.                                                │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/mem/mem.h"
#include "third_party/dlmalloc/dlmalloc.h"

/**
 * Resizes the space allocated for p to size n, only if this can be
 * done without moving p (i.e., only if there is adjacent space
 * available if n is greater than p's current allocated size, or n
 * is less than or equal to p's size). This may be used instead of
 * plain realloc if an alternative allocation strategy is needed
 * upon failure to expand space, for example, reallocation of a
 * buffer that must be memory-aligned or cleared. You can use
 * realloc_in_place to trigger these alternatives only when needed.
 *
 * @param p is address of current allocation
 * @param n is number of bytes needed
 * @return rax is result, or NULL w/ errno
 * @see dlrealloc_in_place()
 */
void *realloc_in_place(void *p, size_t n) {
  return dlrealloc_in_place(p, n);
}