diff options
Diffstat (limited to 'REORG.TODO/sysdeps/tile/tilegx/strnlen.c')
-rw-r--r-- | REORG.TODO/sysdeps/tile/tilegx/strnlen.c | 57 |
1 files changed, 57 insertions, 0 deletions
diff --git a/REORG.TODO/sysdeps/tile/tilegx/strnlen.c b/REORG.TODO/sysdeps/tile/tilegx/strnlen.c new file mode 100644 index 0000000000..5d73a14926 --- /dev/null +++ b/REORG.TODO/sysdeps/tile/tilegx/strnlen.c @@ -0,0 +1,57 @@ +/* Copyright (C) 2013-2017 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/>. */ + +#include <string.h> +#include <stdint.h> +#include "string-endian.h" + +/* Find the length of S, but scan at most MAXLEN characters. If no + '\0' terminator is found in that many characters, return MAXLEN. */ +size_t +__strnlen (const char *s, size_t maxlen) +{ + /* When maxlen is 0, can't read any bytes or it might cause a page fault. */ + if (maxlen == 0) + return 0; + + /* Get an aligned pointer. */ + const uintptr_t s_int = (uintptr_t) s; + const uint64_t *p = (const uint64_t *) (s_int & -8); + size_t bytes_read = sizeof (*p) - (s_int & (sizeof (*p) - 1)); + + /* Read and MASK the first word. */ + uint64_t v = *p | MASK (s_int); + + uint64_t bits; + while ((bits = __insn_v1cmpeqi (v, 0)) == 0) + { + if (bytes_read >= maxlen) + { + /* Read maxlen bytes and didn't find the terminator. */ + return maxlen; + } + v = *++p; + bytes_read += sizeof (v); + } + + /* Found '\0', check it is not larger than maxlen */ + size_t len = ((const char *) p) + (CFZ (bits) >> 3) - s; + return (len < maxlen ? len : maxlen); +} +libc_hidden_def (__strnlen) +weak_alias (__strnlen, strnlen) +libc_hidden_def (strnlen) |