cosmopolitan/libc/calls/hefty/sortenvp.c

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2020-06-15 14:18:57 +00:00
/*-*- 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;
}