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72 lines
1.9 KiB
C
72 lines
1.9 KiB
C
/* Zero byte detection; indexes. Generic C version.
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Copyright (C) 2023-2024 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#ifndef _STRING_FZI_H
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#define _STRING_FZI_H 1
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#include <limits.h>
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#include <endian.h>
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#include <string-fza.h>
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static __always_inline int
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clz (find_t c)
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{
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if (sizeof (find_t) == sizeof (unsigned long))
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return __builtin_clzl (c);
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else
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return __builtin_clzll (c);
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}
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static __always_inline int
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ctz (find_t c)
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{
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if (sizeof (find_t) == sizeof (unsigned long))
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return __builtin_ctzl (c);
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else
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return __builtin_ctzll (c);
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}
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/* A subroutine for the index_zero functions. Given a test word C, return
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the (memory order) index of the first byte (in memory order) that is
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non-zero. */
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static __always_inline unsigned int
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index_first (find_t c)
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{
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int r;
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if (__BYTE_ORDER == __LITTLE_ENDIAN)
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r = ctz (c);
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else
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r = clz (c);
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return r / CHAR_BIT;
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}
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/* Similarly, but return the (memory order) index of the last byte that is
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non-zero. */
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static __always_inline unsigned int
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index_last (find_t c)
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{
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int r;
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if (__BYTE_ORDER == __LITTLE_ENDIAN)
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r = clz (c);
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else
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r = ctz (c);
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return sizeof (find_t) - 1 - (r / CHAR_BIT);
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}
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#endif /* STRING_FZI_H */
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