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-rw-r--r--lib/unistr/u8-strrchr.c101
1 files changed, 101 insertions, 0 deletions
diff --git a/lib/unistr/u8-strrchr.c b/lib/unistr/u8-strrchr.c
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+++ b/lib/unistr/u8-strrchr.c
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+/* Search character in UTF-8 string.
+ Copyright (C) 1999, 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"
+
+uint8_t *
+u8_strrchr (const uint8_t *s, ucs4_t uc)
+{
+ /* Calling u8_strlen and then searching from the other end would cause more
+ memory accesses. Avoid that, at the cost of a few more comparisons. */
+ uint8_t *result = NULL;
+ uint8_t c[6];
+
+ if (uc < 0x80)
+ {
+ uint8_t c0 = uc;
+
+ for (;; s++)
+ {
+ if (*s == c0)
+ result = (uint8_t *) s;
+ if (*s == 0)
+ break;
+ }
+ }
+ else
+ switch (u8_uctomb_aux (c, uc, 6))
+ {
+ case 2:
+ if (*s)
+ {
+ uint8_t c0 = c[0];
+ uint8_t c1 = c[1];
+
+ /* FIXME: Maybe walking the string via u8_mblen is a win? */
+ for (;; s++)
+ {
+ if (s[1] == 0)
+ break;
+ if (*s == c0 && s[1] == c1)
+ result = (uint8_t *) s;
+ }
+ }
+ break;
+
+ case 3:
+ if (*s && s[1])
+ {
+ uint8_t c0 = c[0];
+ uint8_t c1 = c[1];
+ uint8_t c2 = c[2];
+
+ /* FIXME: Maybe walking the string via u8_mblen is a win? */
+ for (;; s++)
+ {
+ if (s[2] == 0)
+ break;
+ if (*s == c0 && s[1] == c1 && s[2] == c2)
+ result = (uint8_t *) s;
+ }
+ }
+ break;
+
+ case 4:
+ if (*s && s[1] && s[2])
+ {
+ uint8_t c0 = c[0];
+ uint8_t c1 = c[1];
+ uint8_t c2 = c[2];
+ uint8_t c3 = c[3];
+
+ /* FIXME: Maybe walking the string via u8_mblen is a win? */
+ for (;; s++)
+ {
+ if (s[3] == 0)
+ break;
+ if (*s == c0 && s[1] == c1 && s[2] == c2 && s[3] == c3)
+ result = (uint8_t *) s;
+ }
+ }
+ break;
+ }
+ return result;
+}