view src/strcmp.c @ 4686:cdabd56ce1b5

Fix various small issues with the multiple-value implementation. lisp/ChangeLog addition: 2009-08-31 Aidan Kehoe <kehoea@parhasard.net> * byte-optimize.el (byte-optimize-form-code-walker): Be careful about discarding multiple values when optimising #'prog1 calls. (byte-optimize-or): Preserve any trailing nil, as this is a supported way to explicitly discard multiple values. (byte-optimize-cond-1): Discard multiple values with a singleton followed by no more clauses. * bytecomp.el (progn): (prog1): (prog2): Be careful about discarding multiple values in the byte-hunk handler of these three forms. * bytecomp.el (byte-compile-prog1, byte-compile-prog2): Don't call #'values explicitly, use `(or ,(pop form) nil) instead, since that compiles to bytecode, not a funcall. * bytecomp.el (byte-compile-values): With one non-const argument, byte-compile to `(or ,(second form) nil), not an explicit #'values call. * bytecomp.el (byte-compile-insert-header): Be nicer in the error message to emacs versions that don't understand our bytecode. src/ChangeLog addition: 2009-08-31 Aidan Kehoe <kehoea@parhasard.net> * eval.c (For, Fand): Don't declare val as REGISTER in these functions, for some reason it breaks the non-DEBUG union build. These functions are only called from interpreted code, the performance implication doesn't matter. Thank you Robert Delius Royar! * eval.c (Fmultiple_value_list_internal): Error on too many arguments. tests/ChangeLog addition: 2009-08-31 Aidan Kehoe <kehoea@parhasard.net> * automated/lisp-tests.el (Assert-rounding): Remove an overly-verbose failure message here. Correct a couple of tests which were buggy in themselves. Add three new tests, checking the behaviour of #'or and #'and when passed zero arguments, and a Known-Bug-Expect-Failure call involving letf and values. (The bug predates the C-level multiple-value implementation.)
author Aidan Kehoe <kehoea@parhasard.net>
date Sun, 06 Sep 2009 19:36:02 +0100
parents abe6d1db359e
children
line wrap: on
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/* This file is part of XEmacs.

XEmacs is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation; either version 2, or (at your option) any
later version.

XEmacs 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 General Public License
for more details.

You should have received a copy of the GNU General Public License
along with XEmacs; see the file COPYING.  If not, write to
the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.  */

/* Synched up with: Not in FSF. */

/* In SunOS 4.1.1 the strcmp and strncmp functions reference memory
   past the last byte of the string! This will core dump if the memory 
   following the last byte is not mapped.

   Here are correct versions by hbs@lucid.com.
*/

# include <config.h>
# ifndef REGISTER	/* Strictly enforced in 20.3 */
# define REGISTER
# endif

#include <string.h>
#define ALIGNED(x) (!(((unsigned long) (x)) & (sizeof (unsigned long) - 1)))

#define MAGIC    0x7efefeff
#define HIGH_BIT_P(c) ((c) & hi_bit)
#define HAS_ZERO(c) (((((c) + magic) ^ (c)) & not_magic) != not_magic)

int
strcmp (const char *x, const char *y)
{
  if (x == y)
    return 0;
  else if (ALIGNED (x) && ALIGNED (y))
    {
      const unsigned long *x1 = (const unsigned long *) x;
      const unsigned long *y1 = (const unsigned long *) y;
      unsigned long c;
      unsigned long magic = MAGIC;
      unsigned long not_magic = ~magic;
      unsigned long hi_bit = 0x80000000;

      while ((c = *x1) == *y1)
        {
          if (HAS_ZERO(c)) 
            {
              if (!HIGH_BIT_P (c))
                return 0;
              else
                {
                  x = (const char *) x1;
                  y = (const char *) y1;
                  goto slow_loop;
                }
            }
              
          x1++; 
          y1++;
        }

      x = (const char *) x1;
      y = (const char *) y1;
      goto slow_loop;
    }
  else
    {
      char c;

    slow_loop:

      while ((c = *x) == *y)
        {
          if (c == (char) 0) return 0;
          x++; 
          y++;
        }
      return (*x - *y);
    }
}


int
strncmp (const char *x, const char *y, size_t n)
{
  if ((x == y) || (n <= 0))
    return 0;
  else if (ALIGNED (x) && ALIGNED (y))
    {
      const unsigned long *x1 = (const unsigned long *) x;
      const unsigned long *y1 = (const unsigned long *) y;
      unsigned long c;
      unsigned long magic = MAGIC;
      unsigned long not_magic = ~magic;
      unsigned long hi_bit = 0x80000000;

      while ((c = *x1) == *y1)
        {
          n -= sizeof (unsigned long);
          if (n <= 0)
            return 0;
          
          if (HAS_ZERO(c)) 
            {
              if (!HIGH_BIT_P (c))
                return 0;
              else
                {
                  x = (const char *) x1;
                  y = (const char *) y1;
                  goto slow_loop;
                }
            }
              
          x1++; 
          y1++;
        }

      x = (const char *) x1;
      y = (const char *) y1;
      goto slow_loop;
    }
  else
    {
      char c;

    slow_loop:

      while ((c = *x) == *y)
        {
          n--;
          if (n <= 0)
            return 0;
          if (c == (char) 0) 
            return 0;
          x++; 
          y++;
        }
      return (*x - *y);
    }
}