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8667f90ec5
Clean up string functions that do not have a version in gnulib on the assumption that glibc is the canonical upstream copy of this code. basename has a copy in gnulib but it is largely written to handle Windows paths so merging it is not really viable. The changes mostly consist of switching to ANSI function prototypes and removing unused includes. As many of these functions do not get built in a typical build due to architecture optimized versions being used instead I built these by hand to verify there were no build warnings and the code was identical. 2014-04-07 Will Newton <will.newton@linaro.org> * string/basename.c [HAVE_CONFIG_H]: Remove #ifdef and and contents. [!_LIBC] Remove #ifndef and contents. (basename): Use ANSI prototype. [_LIBC] Remove #idef. * string/memccpy.c (__memccpy): Use ANSI prototype. * string/memfrob.c (memfrob): Likewise. * string/strcoll.c (STRCOLL): Likewise. * string/strlen.c (strlen): Likewise. * string/strtok.c (STRTOK): Likewise. * string/strcat.c: Remove unused #include of memcopy.h. (strcat): Use ANSI prototype. * string/strchr.c: Remove unused #include of memcopy.h. (strchr): Use ANSI prototype. * string/strcmp.c: Remove unused #include of memcopy.h. (strcmp): Use ANSI prototype. * string/strcpy.c: Remove unused #include of memcopy.h. (strcpy): Use ANSI prototype.
106 lines
3.4 KiB
C
106 lines
3.4 KiB
C
/* Copyright (C) 1991-2014 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Written by Torbjorn Granlund (tege@sics.se),
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with help from Dan Sahlin (dan@sics.se);
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commentary by Jim Blandy (jimb@ai.mit.edu).
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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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#include <string.h>
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#include <stdlib.h>
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#undef strlen
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/* Return the length of the null-terminated string STR. Scan for
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the null terminator quickly by testing four bytes at a time. */
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size_t
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strlen (const char *str)
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{
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const char *char_ptr;
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const unsigned long int *longword_ptr;
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unsigned long int longword, himagic, lomagic;
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/* Handle the first few characters by reading one character at a time.
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Do this until CHAR_PTR is aligned on a longword boundary. */
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for (char_ptr = str; ((unsigned long int) char_ptr
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& (sizeof (longword) - 1)) != 0;
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++char_ptr)
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if (*char_ptr == '\0')
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return char_ptr - str;
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/* All these elucidatory comments refer to 4-byte longwords,
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but the theory applies equally well to 8-byte longwords. */
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longword_ptr = (unsigned long int *) char_ptr;
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/* Bits 31, 24, 16, and 8 of this number are zero. Call these bits
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the "holes." Note that there is a hole just to the left of
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each byte, with an extra at the end:
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bits: 01111110 11111110 11111110 11111111
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bytes: AAAAAAAA BBBBBBBB CCCCCCCC DDDDDDDD
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The 1-bits make sure that carries propagate to the next 0-bit.
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The 0-bits provide holes for carries to fall into. */
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himagic = 0x80808080L;
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lomagic = 0x01010101L;
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if (sizeof (longword) > 4)
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{
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/* 64-bit version of the magic. */
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/* Do the shift in two steps to avoid a warning if long has 32 bits. */
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himagic = ((himagic << 16) << 16) | himagic;
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lomagic = ((lomagic << 16) << 16) | lomagic;
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}
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if (sizeof (longword) > 8)
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abort ();
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/* Instead of the traditional loop which tests each character,
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we will test a longword at a time. The tricky part is testing
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if *any of the four* bytes in the longword in question are zero. */
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for (;;)
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{
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longword = *longword_ptr++;
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if (((longword - lomagic) & ~longword & himagic) != 0)
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{
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/* Which of the bytes was the zero? If none of them were, it was
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a misfire; continue the search. */
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const char *cp = (const char *) (longword_ptr - 1);
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if (cp[0] == 0)
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return cp - str;
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if (cp[1] == 0)
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return cp - str + 1;
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if (cp[2] == 0)
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return cp - str + 2;
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if (cp[3] == 0)
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return cp - str + 3;
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if (sizeof (longword) > 4)
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{
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if (cp[4] == 0)
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return cp - str + 4;
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if (cp[5] == 0)
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return cp - str + 5;
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if (cp[6] == 0)
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return cp - str + 6;
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if (cp[7] == 0)
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return cp - str + 7;
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}
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}
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}
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}
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libc_hidden_builtin_def (strlen)
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