LCOV - code coverage report
Current view: top level - lib/gllib - hash-pjw-bare.c (source / functions) Hit Total Coverage
Test: GNU Libtasn1 Lines: 6 6 100.0 %
Date: 2013-03-24 Functions: 1 1 100.0 %
Legend: Lines: hit not hit | Branches: + taken - not taken # not executed Branches: 2 2 100.0 %

           Branch data     Line data    Source code
       1                 :            : /* hash-pjw-bare.c -- compute a hash value from a provided buffer.
       2                 :            : 
       3                 :            :    Copyright (C) 2012-2013 Free Software Foundation, Inc.
       4                 :            : 
       5                 :            :    This program is free software: you can redistribute it and/or modify it
       6                 :            :    under the terms of the GNU Lesser General Public License as published
       7                 :            :    by the Free Software Foundation; either version 2.1 of the License, or
       8                 :            :    (at your option) any later version.
       9                 :            : 
      10                 :            :    This program is distributed in the hope that it will be useful,
      11                 :            :    but WITHOUT ANY WARRANTY; without even the implied warranty of
      12                 :            :    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      13                 :            :    Lesser General Public License for more details.
      14                 :            : 
      15                 :            :    You should have received a copy of the GNU Lesser General Public License
      16                 :            :    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
      17                 :            : 
      18                 :            : #include <config.h>
      19                 :            : 
      20                 :            : #include "hash-pjw-bare.h"
      21                 :            : 
      22                 :            : #include <limits.h>
      23                 :            : 
      24                 :            : #define SIZE_BITS (sizeof (size_t) * CHAR_BIT)
      25                 :            : 
      26                 :            : /* Return a hash of the N bytes of X using the method described by
      27                 :            :    Bruno Haible in http://www.haible.de/bruno/hashfunc.html.
      28                 :            :    Note that while many hash functions reduce their result via modulo
      29                 :            :    to a 0..table_size-1 range, this function does not do that.  */
      30                 :            : 
      31                 :            : size_t
      32                 :       4703 : hash_pjw_bare (const void *x, size_t n)
      33                 :            : {
      34                 :       4703 :   const unsigned char *s = x;
      35                 :       4703 :   size_t h = 0;
      36                 :            :   unsigned i;
      37                 :            : 
      38         [ +  + ]:      52001 :   for (i = 0; i < n; i++)
      39                 :      47298 :     h = s[i] + ((h << 9) | (h >> (SIZE_BITS - 9)));
      40                 :            : 
      41                 :       4703 :   return h;
      42                 :            : }

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