/*-*- 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 2022 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/mem/mem.h"
#include "third_party/lua/visitor.h"

static inline bool IsVisited(struct LuaVisited *v, const void *p) {
  int i;
  for (i = 0; i < v->i; ++i) {
    if (v->p[i] == p) {
      return true;
    }
  }
  return false;
}

static inline int Visit(struct LuaVisited *v, const void *p) {
  int n2;
  const void **p2;
  if (v->i == v->n) {
    n2 = v->n;
    if (!n2) n2 = 2;
    n2 += n2 >> 1;
    if ((p2 = realloc(v->p, n2 * sizeof(*p2)))) {
      v->p = p2;
      v->n = n2;
    } else {
      return -1;
    }
  }
  v->p[v->i++] = p;
  return 0;
}

int LuaPushVisit(struct LuaVisited *v, const void *p) {
  if (IsVisited(v, p)) return 1;
  return Visit(v, p);
}

void LuaPopVisit(struct LuaVisited *v) {
  assert(v->i > 0);
  --v->i;
}