cosmopolitan/libc/str/getutf16.ncabi.c

49 lines
2.6 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/errno.h"
#include "libc/str/str.h"
#include "libc/str/utf16.h"
/* TODO: DELETE */
/**
* Decodes UTF-16 character.
*
* @param s is a NUL-terminated string
* @return number of bytes (NUL counts as 1) or -1 w/ errno
* @note synchronization is performed to skip leading continuations;
* canonicalization and validation are performed to some extent
* @todo delete
*/
forcealignargpointer unsigned(getutf16)(const char16_t *p, wint_t *wc) {
unsigned skip = 0;
while (IsUtf16Cont(p[skip])) skip++;
if (IsUcs2(p[skip])) {
*wc = p[skip];
return skip + 1;
} else if (!IsUtf16Cont(p[skip + 1])) {
*wc = INVALID_CODEPOINT;
return -1;
} else {
*wc = MergeUtf16(p[skip], p[skip + 1]);
return skip + 2;
}
}