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-rw-r--r--sysdeps/generic/string-fzi.h71
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+/* Zero byte detection; indexes. Generic C version.
+ Copyright (C) 2023 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ 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/>. */
+
+#ifndef _STRING_FZI_H
+#define _STRING_FZI_H 1
+
+#include <limits.h>
+#include <endian.h>
+#include <string-fza.h>
+
+static __always_inline int
+clz (find_t c)
+{
+ if (sizeof (find_t) == sizeof (unsigned long))
+ return __builtin_clzl (c);
+ else
+ return __builtin_clzll (c);
+}
+
+static __always_inline int
+ctz (find_t c)
+{
+ if (sizeof (find_t) == sizeof (unsigned long))
+ return __builtin_ctzl (c);
+ else
+ return __builtin_ctzll (c);
+}
+
+/* A subroutine for the index_zero functions. Given a test word C, return
+ the (memory order) index of the first byte (in memory order) that is
+ non-zero. */
+static __always_inline unsigned int
+index_first (find_t c)
+{
+ int r;
+ if (__BYTE_ORDER == __LITTLE_ENDIAN)
+ r = ctz (c);
+ else
+ r = clz (c);
+ return r / CHAR_BIT;
+}
+
+/* Similarly, but return the (memory order) index of the last byte that is
+ non-zero. */
+static __always_inline unsigned int
+index_last (find_t c)
+{
+ int r;
+ if (__BYTE_ORDER == __LITTLE_ENDIAN)
+ r = clz (c);
+ else
+ r = ctz (c);
+ return sizeof (find_t) - 1 - (r / CHAR_BIT);
+}
+
+#endif /* STRING_FZI_H */