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-rw-r--r--sysdeps/generic/strchrnul.c170
1 files changed, 0 insertions, 170 deletions
diff --git a/sysdeps/generic/strchrnul.c b/sysdeps/generic/strchrnul.c
deleted file mode 100644
index 88b96dd126..0000000000
--- a/sysdeps/generic/strchrnul.c
+++ /dev/null
@@ -1,170 +0,0 @@
-/* Copyright (C) 1991,1993-1997,99,2000,2005 Free Software Foundation, Inc.
- This file is part of the GNU C Library.
- Based on strlen implementation by Torbjorn Granlund (tege@sics.se),
- with help from Dan Sahlin (dan@sics.se) and
- bug fix and commentary by Jim Blandy (jimb@ai.mit.edu);
- adaptation to strchr suggested by Dick Karpinski (dick@cca.ucsf.edu),
- and implemented by Roland McGrath (roland@ai.mit.edu).
-
- 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, write to the Free
- Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
- 02111-1307 USA. */
-
-#include <string.h>
-#include <memcopy.h>
-#include <stdlib.h>
-
-#undef __strchrnul
-#undef strchrnul
-
-/* Find the first occurrence of C in S or the final NUL byte. */
-char *
-__strchrnul (s, c_in)
- const char *s;
- int c_in;
-{
- const unsigned char *char_ptr;
- const unsigned long int *longword_ptr;
- unsigned long int longword, magic_bits, charmask;
- unsigned reg_char c;
-
- c = (unsigned char) c_in;
-
- /* Handle the first few characters by reading one character at a time.
- Do this until CHAR_PTR is aligned on a longword boundary. */
- for (char_ptr = (const unsigned char *) s;
- ((unsigned long int) char_ptr & (sizeof (longword) - 1)) != 0;
- ++char_ptr)
- if (*char_ptr == c || *char_ptr == '\0')
- return (void *) char_ptr;
-
- /* All these elucidatory comments refer to 4-byte longwords,
- but the theory applies equally well to 8-byte longwords. */
-
- longword_ptr = (unsigned long int *) char_ptr;
-
- /* Bits 31, 24, 16, and 8 of this number are zero. Call these bits
- the "holes." Note that there is a hole just to the left of
- each byte, with an extra at the end:
-
- bits: 01111110 11111110 11111110 11111111
- bytes: AAAAAAAA BBBBBBBB CCCCCCCC DDDDDDDD
-
- The 1-bits make sure that carries propagate to the next 0-bit.
- The 0-bits provide holes for carries to fall into. */
- switch (sizeof (longword))
- {
- case 4: magic_bits = 0x7efefeffL; break;
- case 8: magic_bits = ((0x7efefefeL << 16) << 16) | 0xfefefeffL; break;
- default:
- abort ();
- }
-
- /* Set up a longword, each of whose bytes is C. */
- charmask = c | (c << 8);
- charmask |= charmask << 16;
- if (sizeof (longword) > 4)
- /* Do the shift in two steps to avoid a warning if long has 32 bits. */
- charmask |= (charmask << 16) << 16;
- if (sizeof (longword) > 8)
- abort ();
-
- /* Instead of the traditional loop which tests each character,
- we will test a longword at a time. The tricky part is testing
- if *any of the four* bytes in the longword in question are zero. */
- for (;;)
- {
- /* We tentatively exit the loop if adding MAGIC_BITS to
- LONGWORD fails to change any of the hole bits of LONGWORD.
-
- 1) Is this safe? Will it catch all the zero bytes?
- Suppose there is a byte with all zeros. Any carry bits
- propagating from its left will fall into the hole at its
- least significant bit and stop. Since there will be no
- carry from its most significant bit, the LSB of the
- byte to the left will be unchanged, and the zero will be
- detected.
-
- 2) Is this worthwhile? Will it ignore everything except
- zero bytes? Suppose every byte of LONGWORD has a bit set
- somewhere. There will be a carry into bit 8. If bit 8
- is set, this will carry into bit 16. If bit 8 is clear,
- one of bits 9-15 must be set, so there will be a carry
- into bit 16. Similarly, there will be a carry into bit
- 24. If one of bits 24-30 is set, there will be a carry
- into bit 31, so all of the hole bits will be changed.
-
- The one misfire occurs when bits 24-30 are clear and bit
- 31 is set; in this case, the hole at bit 31 is not
- changed. If we had access to the processor carry flag,
- we could close this loophole by putting the fourth hole
- at bit 32!
-
- So it ignores everything except 128's, when they're aligned
- properly.
-
- 3) But wait! Aren't we looking for C as well as zero?
- Good point. So what we do is XOR LONGWORD with a longword,
- each of whose bytes is C. This turns each byte that is C
- into a zero. */
-
- longword = *longword_ptr++;
-
- /* Add MAGIC_BITS to LONGWORD. */
- if ((((longword + magic_bits)
-
- /* Set those bits that were unchanged by the addition. */
- ^ ~longword)
-
- /* Look at only the hole bits. If any of the hole bits
- are unchanged, most likely one of the bytes was a
- zero. */
- & ~magic_bits) != 0 ||
-
- /* That caught zeroes. Now test for C. */
- ((((longword ^ charmask) + magic_bits) ^ ~(longword ^ charmask))
- & ~magic_bits) != 0)
- {
- /* Which of the bytes was C or zero?
- If none of them were, it was a misfire; continue the search. */
-
- const unsigned char *cp = (const unsigned char *) (longword_ptr - 1);
-
- if (*cp == c || *cp == '\0')
- return (char *) cp;
- if (*++cp == c || *cp == '\0')
- return (char *) cp;
- if (*++cp == c || *cp == '\0')
- return (char *) cp;
- if (*++cp == c || *cp == '\0')
- return (char *) cp;
- if (sizeof (longword) > 4)
- {
- if (*++cp == c || *cp == '\0')
- return (char *) cp;
- if (*++cp == c || *cp == '\0')
- return (char *) cp;
- if (*++cp == c || *cp == '\0')
- return (char *) cp;
- if (*++cp == c || *cp == '\0')
- return (char *) cp;
- }
- }
- }
-
- /* This should never happen. */
- return NULL;
-}
-
-weak_alias (__strchrnul, strchrnul)
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