/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Copyright 2020 Justine Alexandra Roberts Tunney                              │
│                                                                              │
│ This program is free software; you can redistribute it and/or modify         │
│ it under the terms of the GNU General Public License as published by         │
│ the Free Software Foundation; version 2 of the License.                      │
│                                                                              │
│ This program is distributed in the hope that it will be useful, but          │
│ WITHOUT ANY WARRANTY; without even the implied warranty of                   │
│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU             │
│ General Public License for more details.                                     │
│                                                                              │
│ You should have received a copy of the GNU General Public License            │
│ along with this program; if not, write to the Free Software                  │
│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA                │
│ 02110-1301 USA                                                               │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/alg/alg.h"
#include "libc/alg/arraylist.h"
#include "libc/calls/hefty/ntspawn.h"
#include "libc/dce.h"
#include "libc/nexgen32e/tinystrcmp.h"
#include "libc/str/str.h"

static int sortenvpcb(const char **a, const char **b) { return strcmp(*a, *b); }

static void slowsort(char **a, int n) {
  size_t i, j;
  const char *t;
  for (i = 1; i < n; ++i) {
    j = i;
    t = a[i];
    while (j > 0 && tinystrcmp(t, a[j - 1]) < 0) {
      a[j] = a[j - 1];
      --j;
    }
    a[j] = t;
  }
}

/**
 * Copies environment variable pointers and sorts them.
 *
 * This is useful for (a) binary searching; and (b) keeping the NT
 * Executive happy, which wants strings to be ordered by UNICODE
 * codepoint identifiers. That's basically what uint8_t comparisons on
 * UTF8-encoded data gives us.
 *
 * @param envp is a NULL-terminated string array
 * @return newly allocated sorted copy of envp pointer array
 */
hidden textwindows nodiscard char **sortenvp(char *const envp[]) {
  size_t count = 0;
  while (envp[count]) count++;
  size_t bytesize = (count + 1) * sizeof(char *);
  char **copy = malloc(bytesize);
  if (copy) {
    memcpy(copy, envp, bytesize);
    if (IsTiny()) {
      slowsort(copy, count);
    } else {
      qsort(copy, count, sizeof(char *), (void *)sortenvpcb);
    }
  }
  return copy;
}