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-rw-r--r--lib/unistr/u32-prev.c39
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diff --git a/lib/unistr/u32-prev.c b/lib/unistr/u32-prev.c
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+++ b/lib/unistr/u32-prev.c
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+/* Iterate over previous character in UTF-32 string.
+ Copyright (C) 2002, 2006-2007 Free Software Foundation, Inc.
+ Written by Bruno Haible <bruno@clisp.org>, 2002.
+
+ This program 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 3 of the License, or
+ (at your option) any later version.
+
+ 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
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
+
+#include <config.h>
+
+/* Specification. */
+#include "unistr.h"
+
+const uint32_t *
+u32_prev (ucs4_t *puc, const uint32_t *s, const uint32_t *start)
+{
+ if (s != start)
+ {
+ uint32_t c_1 = s[-1];
+
+#if CONFIG_UNICODE_SAFETY
+ if (c_1 < 0xd800 || (c_1 >= 0xe000 && c_1 < 0x110000))
+#endif
+ {
+ *puc = c_1;
+ return s - 1;
+ }
+ }
+ return NULL;
+}