cosmopolitan/libc/calls/hefty/sortenvp.c

67 lines
3.1 KiB
C

/*-*- 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 CompareStrings(const char *l, const char *r) {
size_t i = 0;
while (l[i] == r[i] && r[i]) ++i;
return (l[i] & 0xff) - (r[i] & 0xff);
}
static void SortStrings(char **a, size_t n) {
char *t;
size_t i, j;
for (i = 1; i < n; ++i) {
for (t = a[i], j = i; j > 0 && CompareStrings(t, a[j - 1]) < 0; --j) {
a[j] = a[j - 1];
}
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[]) {
char **copy;
size_t n, size;
n = 0;
while (envp[n]) n++;
size = (n + 1) * sizeof(char *);
if ((copy = malloc(size))) {
memcpy(copy, envp, size);
SortStrings(copy, n);
}
return copy;
}