src/getlimits.c

   1 /* getlimits - print various platform dependent limits.
   2    Copyright (C) 2008-2010 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 <http://www.gnu.org/licenses/>.  */
  16
  17 /* Written by Pádraig Brady  */
  18
  19 #include <config.h>             /* sets _FILE_OFFSET_BITS=64 etc. */
  20 #include <stdio.h>
  21 #include <sys/types.h>
  22 #include <float.h>
  23
  24 #include "system.h"
  25 #include "c-ctype.h"
  26 #include "long-options.h"
  27
  28 #define PROGRAM_NAME "getlimits"
  29
  30 #define AUTHORS proper_name_utf8 ("Padraig Brady", "P\303\241draig Brady")
  31
  32 #ifndef TIME_T_MAX
  33 # define TIME_T_MAX TYPE_MAXIMUM (time_t)
  34 #endif
  35
  36 #ifndef TIME_T_MIN
  37 # define TIME_T_MIN TYPE_MINIMUM (time_t)
  38 #endif
  39
  40 #ifndef SSIZE_MIN
  41 # define SSIZE_MIN TYPE_MINIMUM (ssize_t)
  42 #endif
  43
  44 #ifndef PID_T_MIN
  45 # define PID_T_MIN TYPE_MINIMUM (pid_t)
  46 #endif
  47
  48 /* These are not interesting to print.
  49  * Instead of these defines it would be nice to be able to do
  50  * #ifdef (TYPE##_MIN) in function macro below.  */
  51 #define SIZE_MIN 0
  52 #define UCHAR_MIN 0
  53 #define UINT_MIN 0
  54 #define ULONG_MIN 0
  55 #define UINTMAX_MIN 0
  56 #define UID_T_MIN 0
  57 #define GID_T_MIN 0
  58
  59 void
  60 usage (int status)
  61 {
  62   if (status != EXIT_SUCCESS)
  63     fprintf (stderr, _("Try `%s --help' for more information.\n"),
  64              program_name);
  65   else
  66     {
  67       printf (_("\
  68 Usage: %s\n\
  69 "), program_name);
  70
  71       fputs (_("\
  72 Output platform dependent limits in a format useful for shell scripts.\n\
  73 \n\
  74 "), stdout);
  75       fputs (HELP_OPTION_DESCRIPTION, stdout);
  76       fputs (VERSION_OPTION_DESCRIPTION, stdout);
  77       emit_ancillary_info ();
  78     }
  79   exit (status);
  80 }
  81
  82 /* Add absolute values of ascii decimal strings.
  83  * Strings can have leading spaces.
  84  * If any string has a '-' it's preserved in the output:
  85  * I.E.
  86  *    1 +  1 ->  2
  87  *   -1 + -1 -> -2
  88  *   -1 +  1 -> -2
  89  *    1 + -1 -> -2
  90  */
  91 static char *
  92 decimal_ascii_add (const char *str1, const char *str2)
  93 {
  94   int len1 = strlen (str1);
  95   int len2 = strlen (str2);
  96   int rlen = MAX (len1, len2) + 3;  /* space for extra digit or sign + NUL */
  97   char *result = xmalloc (rlen);
  98   char *rp = result + rlen - 1;
  99   const char *d1 = str1 + len1 - 1;
 100   const char *d2 = str2 + len2 - 1;
 101   int carry = 0;
 102   *rp = '\0';
 103
 104   while (1)
 105     {
 106       char c1 = (d1 < str1 ? ' ' : (*d1 == '-' ? ' ' : *d1--));
 107       char c2 = (d2 < str2 ? ' ' : (*d2 == '-' ? ' ' : *d2--));
 108       char t1 = c1 + c2 + carry;    /* ASCII digits are BCD */
 109       if (!c_isdigit (c1) && !c_isdigit (c2) && !carry)
 110         break;
 111       carry = t1 > '0' + '9' || t1 == ' ' + '9' + 1;
 112       t1 += 6 * carry;
 113       *--rp = (t1 & 0x0F) | 0x30;   /* top nibble to ASCII */
 114     }
 115   if ((d1 >= str1 && *d1 == '-') || (d2 >= str2 && (*d2 == '-')))
 116     *--rp = '-';
 117
 118   if (rp != result)
 119     memmove (result, rp, rlen - (rp - result));
 120
 121   return result;
 122 }
 123
 124 int
 125 main (int argc, char **argv)
 126 {
 127   char limit[64];               /* big enough for 128 bit integers at least */
 128   char *oflow;
 129
 130   initialize_main (&argc, &argv);
 131   set_program_name (argv[0]);
 132   setlocale (LC_ALL, "");
 133   bindtextdomain (PACKAGE, LOCALEDIR);
 134   textdomain (PACKAGE);
 135
 136   initialize_exit_failure (EXIT_FAILURE);
 137   atexit (close_stdout);
 138
 139   parse_long_options (argc, argv, PROGRAM_NAME, PACKAGE_NAME, VERSION,
 140                       usage, AUTHORS, (char const *) NULL);
 141
 142 #define print_int(TYPE)                                                  \
 143   snprintf (limit, sizeof limit, "%"PRIuMAX, (uintmax_t)TYPE##_MAX);     \
 144   printf (#TYPE"_MAX=%s\n", limit);                                      \
 145   oflow = decimal_ascii_add (limit, "1");                                \
 146   printf (#TYPE"_OFLOW=%s\n", oflow);                                    \
 147   free (oflow);                                                          \
 148   if (TYPE##_MIN)                                                        \
 149     {                                                                    \
 150       snprintf (limit, sizeof limit, "%"PRIdMAX, (intmax_t)TYPE##_MIN);  \
 151       printf (#TYPE"_MIN=%s\n", limit);                                  \
 152       oflow = decimal_ascii_add (limit, "-1");                           \
 153       printf (#TYPE"_UFLOW=%s\n", oflow);                                \
 154       free (oflow);                                                      \
 155     }
 156
 157 #define print_float(TYPE)                                                \
 158   printf (#TYPE"_MIN=%Le\n", (long double)TYPE##_MIN);                   \
 159   printf (#TYPE"_MAX=%Le\n", (long double)TYPE##_MAX);
 160
 161   /* Variable sized ints */
 162   print_int (CHAR);
 163   print_int (SCHAR);
 164   print_int (UCHAR);
 165   print_int (SHRT);
 166   print_int (INT);
 167   print_int (UINT);
 168   print_int (LONG);
 169   print_int (ULONG);
 170   print_int (SIZE);
 171   print_int (SSIZE);
 172   print_int (TIME_T);
 173   print_int (UID_T);
 174   print_int (GID_T);
 175   print_int (PID_T);
 176   print_int (OFF_T);
 177   print_int (INTMAX);
 178   print_int (UINTMAX);
 179
 180   /* Variable sized floats */
 181   print_float (FLT);
 182   print_float (DBL);
 183   print_float (LDBL);
 184 }