lib/hash-triple.c

   1 /* Hash functions for file-related triples: name, device, inode.
   2    Copyright (C) 2007, 2009-2018 Free Software Foundation, Inc.
   3
   4    This program is free software: you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation; either version 3 of the License, or
   7    (at your option) 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
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  16
  17 /* written by Jim Meyering */
  18
  19 #include <config.h>
  20
  21 #include "hash-triple.h"
  22
  23 #include <stdlib.h>
  24 #include <string.h>
  25
  26 #include "hash-pjw.h"
  27 #include "same.h"
  28 #include "same-inode.h"
  29
  30 #define STREQ(a, b) (strcmp (a, b) == 0)
  31
  32 /* Hash an F_triple, and *do* consider the file name.  */
  33 size_t
  34 triple_hash (void const *x, size_t table_size)
  35 {
  36   struct F_triple const *p = x;
  37   size_t tmp = hash_pjw (p->name, table_size);
  38
  39   /* Ignoring the device number here should be fine.  */
  40   return (tmp ^ p->st_ino) % table_size;
  41 }
  42
  43 /* Hash an F_triple, without considering the file name.  */
  44 size_t
  45 triple_hash_no_name (void const *x, size_t table_size)
  46 {
  47   struct F_triple const *p = x;
  48
  49   /* Ignoring the device number here should be fine.  */
  50   return p->st_ino % table_size;
  51 }
  52
  53 /* Compare two F_triple structs.  */
  54 bool
  55 triple_compare (void const *x, void const *y)
  56 {
  57   struct F_triple const *a = x;
  58   struct F_triple const *b = y;
  59   return (SAME_INODE (*a, *b) && same_name (a->name, b->name)) ? true : false;
  60 }
  61
  62 bool
  63 triple_compare_ino_str (void const *x, void const *y)
  64 {
  65   struct F_triple const *a = x;
  66   struct F_triple const *b = y;
  67   return (SAME_INODE (*a, *b) && STREQ (a->name, b->name)) ? true : false;
  68 }
  69
  70 /* Free an F_triple.  */
  71 void
  72 triple_free (void *x)
  73 {
  74   struct F_triple *a = x;
  75   free (a->name);
  76   free (a);
  77 }