[deliverable/binutils-gdb.git] / intl / hash-string.h

/* Description of GNU message catalog format: string hashing function.
   Copyright (C) 1995, 1997, 1998, 2000, 2001 Free Software Foundation, Inc.

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

   This program 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
   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public
   License along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301,
   USA.  */

/* @@ end of prolog @@ */

#ifndef PARAMS
# if __STDC__ || defined __GNUC__ || defined __SUNPRO_C || defined __cplusplus || __PROTOTYPES
#  define PARAMS(Args) Args
# else
#  define PARAMS(Args) ()
# endif
#endif

/* We assume to have `unsigned long int' value with at least 32 bits.  */
#define HASHWORDBITS 32


/* Defines the so called `hashpjw' function by P.J. Weinberger
   [see Aho/Sethi/Ullman, COMPILERS: Principles, Techniques and Tools,
   1986, 1987 Bell Telephone Laboratories, Inc.]  */
static unsigned long int hash_string PARAMS ((const char *__str_param));

static inline unsigned long int
hash_string (str_param)
     const char *str_param;
{
  unsigned long int hval, g;
  const char *str = str_param;

  /* Compute the hash value for the given string.  */
  hval = 0;
  while (*str != '\0')
    {
      hval <<= 4;
      hval += (unsigned long int) *str++;
      g = hval & ((unsigned long int) 0xf << (HASHWORDBITS - 4));
      if (g != 0)
	{
	  hval ^= g >> (HASHWORDBITS - 8);
	  hval ^= g;
	}
    }
  return hval;
}
Commit	Line	Data
	1	/* Description of GNU message catalog format: string hashing function.
	2	Copyright (C) 1995, 1997, 1998, 2000, 2001 Free Software Foundation, Inc.
	3
	4	This program is free software; you can redistribute it and/or modify it
	5	under the terms of the GNU Library General Public License as published
	6	by the Free Software Foundation; either version 2, or (at your option)
	7	any later version.
	8
	9	This program is distributed in the hope that it will be useful,
	10	but WITHOUT ANY WARRANTY; without even the implied warranty of
	11	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	12	Library General Public License for more details.
	13
	14	You should have received a copy of the GNU Library General Public
	15	License along with this program; if not, write to the Free Software
	16	Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301,
	17	USA. */
	18
	19	/* @@ end of prolog @@ */
	20
	21	#ifndef PARAMS
	22	# if __STDC__ \|\| defined __GNUC__ \|\| defined __SUNPRO_C \|\| defined __cplusplus \|\| __PROTOTYPES
	23	# define PARAMS(Args) Args
	24	# else
	25	# define PARAMS(Args) ()
	26	# endif
	27	#endif
	28
	29	/* We assume to have `unsigned long int' value with at least 32 bits. */
	30	#define HASHWORDBITS 32
	31
	32
	33	/* Defines the so called `hashpjw' function by P.J. Weinberger
	34	[see Aho/Sethi/Ullman, COMPILERS: Principles, Techniques and Tools,
	35	1986, 1987 Bell Telephone Laboratories, Inc.] */
	36	static unsigned long int hash_string PARAMS ((const char *__str_param));
	37
	38	static inline unsigned long int
	39	hash_string (str_param)
	40	const char *str_param;
	41	{
	42	unsigned long int hval, g;
	43	const char *str = str_param;
	44
	45	/* Compute the hash value for the given string. */
	46	hval = 0;
	47	while (*str != '\0')
	48	{
	49	hval <<= 4;
	50	hval += (unsigned long int) *str++;
	51	g = hval & ((unsigned long int) 0xf << (HASHWORDBITS - 4));
	52	if (g != 0)
	53	{
	54	hval ^= g >> (HASHWORDBITS - 8);
	55	hval ^= g;
	56	}
	57	}
	58	return hval;
	59	}