X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=lib%2Fmemchr.c;h=fd57586b9b92eb753971c823f13f9b40c9909ac2;hb=5253e5dce47355d4f4490616bafbbabe1097e393;hp=71b1ab5f6ecd9e26c08727a42f69c35939d6e3c6;hpb=69d778f260410d7586953f15e9903cbf41a8a157;p=gnulib.git diff --git a/lib/memchr.c b/lib/memchr.c index 71b1ab5f6..fd57586b9 100644 --- a/lib/memchr.c +++ b/lib/memchr.c @@ -1,5 +1,5 @@ -/* Copyright (C) 1991, 1993 Free Software Foundation, Inc. - Based on strlen implemention by Torbjorn Granlund (tege@sics.se), +/* Copyright (C) 1991, 1993, 1997 Free Software Foundation, Inc. + Based on strlen implementation by Torbjorn Granlund (tege@sics.se), with help from Dan Sahlin (dan@sics.se) and commentary by Jim Blandy (jimb@ai.mit.edu); adaptation to memchr suggested by Dick Karpinski (dick@cca.ucsf.edu), @@ -20,7 +20,8 @@ GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software -Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */ +Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, +USA. */ #ifdef HAVE_CONFIG_H #include @@ -33,12 +34,12 @@ Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */ # define __ptr_t char * #endif /* C++ or ANSI C. */ -#if defined (HAVE_STRING_H) || defined (_LIBC) +#if defined (_LIBC) # include #endif -#if defined (HAVE_LIMIT_H) || defined (_LIBC) -# include +#if defined (HAVE_LIMITS_H) || defined (_LIBC) +# include #endif #define LONG_MAX_32_BITS 2147483647 @@ -66,8 +67,9 @@ memchr (s, c, n) /* 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 = s; n > 0 && ((unsigned long int) char_ptr - & (sizeof (longword) - 1)) != 0; + for (char_ptr = (const unsigned char *) s; + n > 0 && ((unsigned long int) char_ptr + & (sizeof (longword) - 1)) != 0; --n, ++char_ptr) if (*char_ptr == c) return (__ptr_t) char_ptr; @@ -80,9 +82,9 @@ memchr (s, c, n) /* 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 + 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. */ @@ -100,7 +102,7 @@ memchr (s, c, n) charmask = c | (c << 8); charmask |= charmask << 16; #if LONG_MAX > LONG_MAX_32_BITS - charmask |= charmask << 32; + charmask |= charmask << 32; #endif /* Instead of the traditional loop which tests each character, @@ -146,10 +148,10 @@ memchr (s, c, n) /* 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. */