1 files changed, 87 insertions, 0 deletions
diff --git a/lib/libc/locale/wcsftime.c b/lib/libc/locale/wcsftime.c
new file mode 100644
index 0000000..31a1c4c
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+++ b/lib/libc/locale/wcsftime.c
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+/*-
+ * Copyright (c) 2002 Tim J. Robbins
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <limits.h>
+#include <stdlib.h>
+#include <time.h>
+#include <wchar.h>
+
+/*
+ * Convert date and time to a wide-character string.
+ *
+ * This is the wide-character counterpart of strftime(). So that we do not
+ * have to duplicate the code of strftime(), we convert the format string to
+ * multibyte, call strftime(), then convert the result back into wide
+ * characters.
+ *
+ * This technique loses in the presence of stateful multibyte encoding if any
+ * of the conversions in the format string change conversion state. When
+ * stateful encoding is implemented, we will need to reset the state between
+ * format specifications in the format string.
+ */
+size_t
+wcsftime(wchar_t * __restrict wcs, size_t maxsize,
+    const wchar_t * __restrict format, const struct tm * __restrict timeptr)
+{
+	static const mbstate_t initial;
+	mbstate_t state;
+	char *dst, *sformat;
+	size_t n, sflen;
+
+	/*
+	 * Convert the supplied format string to a multibyte representation
+	 * for strftime(), which only handles single-byte characters.
+	 */
+	state = initial;
+	sflen = wcsrtombs(NULL, &format, 0, &state);
+	if (sflen == (size_t)-1)
+		return (0);
+	sformat = alloca(sflen + 1);
+	state = initial;
+	wcsrtombs(sformat, &format, sflen + 1, &state);
+
+	/*
+	 * Allocate memory for longest multibyte sequence that will fit
+	 * into the caller's buffer and call strftime() to fill it.
+	 * Then, copy and convert the result back into wide characters in
+	 * the caller's buffer.
+	 */
+	if (SIZE_T_MAX / MB_CUR_MAX <= maxsize)
+		/* maxsize is prepostorously large - avoid int. overflow. */
+		return (0);
+	dst = alloca(maxsize * MB_CUR_MAX);
+	if (strftime(dst, maxsize, sformat, timeptr) == 0)
+		return (0);
+	state = initial;
+	n = mbsrtowcs(wcs, (const char **)&dst, maxsize, &state);
+	if (n == (size_t)-2 || n == (size_t)-1 || dst != NULL)
+		return (0);
+
+	return (n);
+}