cosmopolitan/libc/runtime/grow.c

/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=8 sts=2 sw=2 fenc=utf-8                                :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2020 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/assert.h"
#include "libc/fmt/conv.h"
#include "libc/intrin/weaken.h"
#include "libc/macros.internal.h"
#include "libc/mem/mem.h"
#include "libc/runtime/runtime.h"
#include "libc/stdckdint.h"
#include "libc/str/str.h"
#include "libc/sysv/errfuns.h"

/* TODO(jart): DELETE */

#define GUARANTEE_TERMINATOR 1
#define INITIAL_CAPACITY     (32 - GUARANTEE_TERMINATOR)

bool __grow(void *pp, size_t *capacity, size_t itemsize, size_t extra) {
  void **p, *p1, *p2;
  size_t n1, n2;
  size_t t1, t2;
  extra += GUARANTEE_TERMINATOR;
  p = (void **)pp;
  unassert(itemsize);
  unassert((*p && *capacity) || (!*p && !*capacity));
  unassert(!_isheap(*p) || ((intptr_t)*p & 15) == 0);
  p1 = _isheap(*p) ? *p : NULL;
  p2 = NULL;
  n1 = *capacity;
  n2 = (*p ? n1 + (n1 >> 1) : MAX(4, INITIAL_CAPACITY / itemsize)) + extra;
  if (!ckd_mul(&t1, n1, itemsize) && !ckd_mul(&t2, n2, itemsize)) {
    if (_weaken(realloc) && (p2 = _weaken(realloc)(p1, ROUNDUP(t2, 32)))) {
      if (!p1 && *p) memcpy(p2, *p, t1);
      bzero((char *)p2 + t1, t2 - t1);
      *capacity = n2;
      *p = p2;
      return true;
    } else {
      enomem();
    }
  } else {
    eoverflow();
  }
  return false;
}