jnlib/mischelp.c

   1 /* mischelp.c - Miscellaneous helper functions
   2  * Copyright (C) 1998, 2000, 2001, 2006, 2007 Free Software Foundation, Inc.
   3  *
   4  * This file is part of JNLIB.
   5  *
   6  * JNLIB is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU Lesser General Public License as
   8  * published by the Free Software Foundation; either version 3 of
   9  * the License, or (at your option) any later version.
  10  *
  11  * JNLIB is distributed in the hope that it will be useful, but
  12  * WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with this program; if not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include <config.h>
  21 #include <stdlib.h>
  22 #include <string.h>
  23 #include <time.h>
  24 #ifdef HAVE_W32_SYSTEM
  25 # define WIN32_LEAN_AND_MEAN
  26 # include <windows.h>
  27 #else /*!HAVE_W32_SYSTEM*/
  28 # include <sys/types.h>
  29 # include <sys/stat.h>
  30 # include <unistd.h>
  31 #endif /*!HAVE_W32_SYSTEM*/
  32
  33 #include "libjnlib-config.h"
  34 #include "stringhelp.h"
  35 #include "mischelp.h"
  36
  37
  38 /* Check whether the files NAME1 and NAME2 are identical.  This is for
  39    example achieved by comparing the inode numbers of the files.  */
  40 int
  41 same_file_p (const char *name1, const char *name2)
  42 {
  43   int yes;
  44
  45   /* First try a shortcut.  */
  46   if (!compare_filenames (name1, name2))
  47     yes = 1;
  48   else
  49     {
  50 #ifdef HAVE_W32_SYSTEM
  51       HANDLE file1, file2;
  52       BY_HANDLE_FILE_INFORMATION info1, info2;
  53
  54       file1 = CreateFile (name1, 0, 0, NULL, OPEN_EXISTING, 0, NULL);
  55       if (file1 == INVALID_HANDLE_VALUE)
  56         yes = 0; /* If we can't open the file, it is not the same.  */
  57       else
  58         {
  59           file2 = CreateFile (name2, 0, 0, NULL, OPEN_EXISTING, 0, NULL);
  60           if (file1 == INVALID_HANDLE_VALUE)
  61             yes = 0; /* If we can't open the file, it is not the same.  */
  62           else
  63             {
  64               yes = (GetFileInformationByHandle (file1, &info1)
  65                      && GetFileInformationByHandle (file2, &info2)
  66                      && info1.dwVolumeSerialNumber==info2.dwVolumeSerialNumber
  67                      && info1.nFileIndexHigh == info2.nFileIndexHigh
  68                      && info1.nFileIndexLow == info2.nFileIndexLow);
  69               CloseHandle (file2);
  70             }
  71           CloseHandle (file1);
  72         }
  73 #else /*!HAVE_W32_SYSTEM*/
  74       struct stat info1, info2;
  75
  76       yes = (!stat (name1, &info1) && !stat (name2, &info2)
  77              && info1.st_dev == info2.st_dev && info1.st_ino == info2.st_ino);
  78 #endif /*!HAVE_W32_SYSTEM*/
  79     }
  80   return yes;
  81 }
  82
  83
  84 /*
  85   timegm() is a GNU function that might not be available everywhere.
  86   It's basically the inverse of gmtime() - you give it a struct tm,
  87   and get back a time_t.  It differs from mktime() in that it handles
  88   the case where the struct tm is UTC and the local environment isn't.
  89
  90   Note, that this replacement implementaion is not thread-safe!
  91
  92   Some BSDs don't handle the putenv("foo") case properly, so we use
  93   unsetenv if the platform has it to remove environment variables.
  94 */
  95 #ifndef HAVE_TIMEGM
  96 time_t
  97 timegm (struct tm *tm)
  98 {
  99   time_t answer;
 100   char *zone;
 101
 102   zone=getenv("TZ");
 103   putenv("TZ=UTC");
 104   tzset();
 105   answer=mktime(tm);
 106   if(zone)
 107     {
 108       static char *old_zone;
 109
 110       if (!old_zone)
 111         {
 112           old_zone = malloc(3+strlen(zone)+1);
 113           if (old_zone)
 114             {
 115               strcpy(old_zone,"TZ=");
 116               strcat(old_zone,zone);
 117             }
 118         }
 119       if (old_zone)
 120         putenv (old_zone);
 121     }
 122   else
 123 #ifdef HAVE_UNSETENV
 124     unsetenv("TZ");
 125 #else
 126     putenv("TZ");
 127 #endif
 128
 129   tzset();
 130   return answer;
 131 }
 132 #endif /*!HAVE_TIMEGM*/
 133