glibc/wcsmbs/c16rtomb.c
Joseph Myers d0a7415979 Handle surrogate pairs in c16rtomb (bug 23794, DR#488, C2X).
The c16rtomb implementation has:

  // XXX The ISO C 11 spec I have does not say anything about handling
  // XXX surrogates in this interface.

The DR#488 resolution, as applied to C2X, requires surrogate pairs to
be handled here (so the first call returns 0 and stores the high
surrogate in the mbstate_t, while the second call combines the
surrogates, produces a multibyte character and returns the number of
bytes written).  This patch implements that.  (mbrtoc16 already
handled producing surrogates as output.)

Tested for x86_64.

	[BZ #23794]
	* wcsmbs/c16rtomb.c (c16rtomb): Save first character of surrogate
	pair and return 0 in that case, and use saved character to
	interpret following character.
	* wcsmbs/tst-c16-surrogate.c: New file.
	* wcsmbs/Makefile (tests): Add tst-c16-surrogate.c.
	[$(run-built-tests) = yes] ($(objpfx)tst-c16-surrogate.out):
	Depend on $(gen-locales)
2018-10-19 16:31:29 +00:00

68 lines
1.9 KiB
C

/* Copyright (C) 2011-2018 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@gmail.com>, 2011.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <uchar.h>
#include <wchar.h>
/* This is the private state used if PS is NULL. */
static mbstate_t state;
size_t
c16rtomb (char *s, char16_t c16, mbstate_t *ps)
{
wchar_t wc = c16;
if (ps == NULL)
ps = &state;
if (s == NULL)
{
/* Reset any state relating to surrogate pairs. */
ps->__count &= 0x7fffffff;
ps->__value.__wch = 0;
wc = 0;
}
if (ps->__count & 0x80000000)
{
/* The previous call passed in the first surrogate of a
surrogate pair. */
ps->__count &= 0x7fffffff;
if (wc >= 0xdc00 && wc < 0xe000)
wc = (0x10000
+ ((ps->__value.__wch & 0x3ff) << 10)
+ (wc & 0x3ff));
else
/* This is not a low surrogate; ensure an EILSEQ error by
trying to decode the high surrogate as a wide character on
its own. */
wc = ps->__value.__wch;
ps->__value.__wch = 0;
}
else if (wc >= 0xd800 && wc < 0xdc00)
{
/* The high part of a surrogate pair. */
ps->__count |= 0x80000000;
ps->__value.__wch = wc;
return 0;
}
return wcrtomb (s, wc, ps);
}