cosmopolitan/libc/runtime/getdosenviron.h

70 lines
3.3 KiB
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 │
│ │
│ 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 │
╚─────────────────────────────────────────────────────────────────────────────*/
#ifndef COSMOPOLITAN_LIBC_DOSENVIRON_H_
#define COSMOPOLITAN_LIBC_DOSENVIRON_H_
#ifndef __STRICT_ANSI__
#include "libc/bits/safemacros.h"
#include "libc/str/appendchar.h"
#if !(__ASSEMBLER__ + __LINKER__ + 0)
/**
* Transcodes NT environment variable block from UTF-16 to UTF-8.
*
* @param env is a double NUL-terminated block of key=values
* @param buf is the new environment
* @param size is the byte capacity of buf
* @param envp stores NULL-terminated string pointer list
* @param max is the pointer count capacity of envp
* @return number of variables decoded, excluding NULL-terminator
*/
static inline int getdosenviron(const char16_t *env, char *buf, size_t size,
char **envp, size_t max) {
const char16_t *s = env;
size_t envc = 0;
if (size) {
wint_t wc;
char *p = buf;
char *pe = buf + size - 1;
if (p < pe) {
s += getutf16(s, &wc);
while (wc) {
if (++envc < max) {
envp[envc - 1] = p < pe ? p : NULL;
}
bool endstring;
do {
AppendChar(&p, pe, wc);
endstring = !wc;
s += getutf16(s, &wc);
} while (!endstring);
buf[min(p - buf, size - 2)] = u'\0';
}
}
AppendChar(&p, pe, '\0');
buf[min(p - buf, size - 1)] = u'\0';
}
if (max) envp[min(envc, max - 1)] = NULL;
return envc;
}
#endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */
#endif /* !ANSI */
#endif /* COSMOPOLITAN_LIBC_DOSENVIRON_H_ */