stdio-common/tst-printf-round.c

   1 /* Test for correct rounding of printf floating-point output.
   2    Copyright (C) 2012-2017 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library 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
  16    License along with the GNU C Library; if not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <fenv.h>
  20 #include <stdio.h>
  21 #include <string.h>
  22
  23 struct dec_test {
  24   double d;
  25   const char *fmt;
  26   const char *rd, *rn, *rz, *ru;
  27 };
  28
  29 static const struct dec_test dec_tests[] = {
  30   { 1.5, "%.0f", "1", "2", "1", "2" },
  31   { -1.5, "%.0f", "-2", "-2", "-1", "-1" },
  32   { 2.5, "%.0f", "2", "2", "2", "3" },
  33   { -2.5, "%.0f", "-3", "-2", "-2", "-2" },
  34   { 1.4999, "%.0f", "1", "1", "1", "2" },
  35   { -1.4999, "%.0f", "-2", "-1", "-1", "-1" },
  36   { 1.5001, "%.0f", "1", "2", "1", "2" },
  37   { -1.5001, "%.0f", "-2", "-2", "-1", "-1" },
  38   { 2.4999, "%.0f", "2", "2", "2", "3" },
  39   { -2.4999, "%.0f", "-3", "-2", "-2", "-2" },
  40   { 2.5001, "%.0f", "2", "3", "2", "3" },
  41   { -2.5001, "%.0f", "-3", "-3", "-2", "-2" },
  42   { 1.0 / 3.0, "%f", "0.333333", "0.333333", "0.333333", "0.333334" },
  43   { -1.0 / 3.0, "%f", "-0.333334", "-0.333333", "-0.333333", "-0.333333" },
  44   { 0.2500001, "%.2e", "2.50e-01", "2.50e-01", "2.50e-01", "2.51e-01" },
  45   { -0.2500001, "%.2e", "-2.51e-01", "-2.50e-01", "-2.50e-01", "-2.50e-01" },
  46   { 1000001.0, "%.1e", "1.0e+06", "1.0e+06", "1.0e+06", "1.1e+06" },
  47   { -1000001.0, "%.1e", "-1.1e+06", "-1.0e+06", "-1.0e+06", "-1.0e+06" },
  48 };
  49
  50 static int
  51 test_dec_in_one_mode (double d, const char *fmt, const char *expected,
  52                       const char *mode_name)
  53 {
  54   char buf[100];
  55   int ret = snprintf (buf, sizeof buf, fmt, d);
  56   if (ret <= 0 || ret >= (int) sizeof buf)
  57     {
  58       printf ("snprintf for %a returned %d\n", d, ret);
  59       return 1;
  60     }
  61   if (strcmp (buf, expected) == 0)
  62     return 0;
  63   else
  64     {
  65       printf ("snprintf (\"%s\", %a) returned \"%s\" not \"%s\" (%s)\n",
  66               fmt, d, buf, expected, mode_name);
  67       return 1;
  68     }
  69 }
  70
  71 struct hex_test
  72 {
  73   double d;
  74   const char *fmt;
  75   const char *rd[4], *rn[4], *rz[4], *ru[4];
  76 };
  77
  78 static const struct hex_test hex_tests[] =
  79   {
  80     {
  81       0x1.fffffp+4, "%.1a",
  82       { "0x1.fp+4", "0x3.fp+3", "0x7.fp+2", "0xf.fp+1" },
  83       { "0x2.0p+4", "0x4.0p+3", "0x8.0p+2", "0x1.0p+5" },
  84       { "0x1.fp+4", "0x3.fp+3", "0x7.fp+2", "0xf.fp+1" },
  85       { "0x2.0p+4", "0x4.0p+3", "0x8.0p+2", "0x1.0p+5" }
  86     },
  87     {
  88       -0x1.fffffp+4, "%.1a",
  89       { "-0x2.0p+4", "-0x4.0p+3", "-0x8.0p+2", "-0x1.0p+5" },
  90       { "-0x2.0p+4", "-0x4.0p+3", "-0x8.0p+2", "-0x1.0p+5" },
  91       { "-0x1.fp+4", "-0x3.fp+3", "-0x7.fp+2", "-0xf.fp+1" },
  92       { "-0x1.fp+4", "-0x3.fp+3", "-0x7.fp+2", "-0xf.fp+1" }
  93     },
  94     {
  95       0x1.88p+4, "%.1a",
  96       { "0x1.8p+4", "0x3.1p+3", "0x6.2p+2", "0xc.4p+1" },
  97       { "0x1.8p+4", "0x3.1p+3", "0x6.2p+2", "0xc.4p+1" },
  98       { "0x1.8p+4", "0x3.1p+3", "0x6.2p+2", "0xc.4p+1" },
  99       { "0x1.9p+4", "0x3.1p+3", "0x6.2p+2", "0xc.4p+1" }
 100     },
 101     {
 102       -0x1.88p+4, "%.1a",
 103       { "-0x1.9p+4", "-0x3.1p+3", "-0x6.2p+2", "-0xc.4p+1" },
 104       { "-0x1.8p+4", "-0x3.1p+3", "-0x6.2p+2", "-0xc.4p+1" },
 105       { "-0x1.8p+4", "-0x3.1p+3", "-0x6.2p+2", "-0xc.4p+1" },
 106       { "-0x1.8p+4", "-0x3.1p+3", "-0x6.2p+2", "-0xc.4p+1" }
 107     },
 108     {
 109       0x1.78p+4, "%.1a",
 110       { "0x1.7p+4", "0x2.fp+3", "0x5.ep+2", "0xb.cp+1" },
 111       { "0x1.8p+4", "0x2.fp+3", "0x5.ep+2", "0xb.cp+1" },
 112       { "0x1.7p+4", "0x2.fp+3", "0x5.ep+2", "0xb.cp+1" },
 113       { "0x1.8p+4", "0x2.fp+3", "0x5.ep+2", "0xb.cp+1" }
 114     },
 115     {
 116       -0x1.78p+4, "%.1a",
 117       { "-0x1.8p+4", "-0x2.fp+3", "-0x5.ep+2", "-0xb.cp+1" },
 118       { "-0x1.8p+4", "-0x2.fp+3", "-0x5.ep+2", "-0xb.cp+1" },
 119       { "-0x1.7p+4", "-0x2.fp+3", "-0x5.ep+2", "-0xb.cp+1" },
 120       { "-0x1.7p+4", "-0x2.fp+3", "-0x5.ep+2", "-0xb.cp+1" }
 121     },
 122     {
 123       64.0 / 3.0, "%.1a",
 124       { "0x1.5p+4", "0x2.ap+3", "0x5.5p+2", "0xa.ap+1" },
 125       { "0x1.5p+4", "0x2.bp+3", "0x5.5p+2", "0xa.bp+1" },
 126       { "0x1.5p+4", "0x2.ap+3", "0x5.5p+2", "0xa.ap+1" },
 127       { "0x1.6p+4", "0x2.bp+3", "0x5.6p+2", "0xa.bp+1" }
 128     },
 129     {
 130       -64.0 / 3.0, "%.1a",
 131       { "-0x1.6p+4", "-0x2.bp+3", "-0x5.6p+2", "-0xa.bp+1" },
 132       { "-0x1.5p+4", "-0x2.bp+3", "-0x5.5p+2", "-0xa.bp+1" },
 133       { "-0x1.5p+4", "-0x2.ap+3", "-0x5.5p+2", "-0xa.ap+1" },
 134       { "-0x1.5p+4", "-0x2.ap+3", "-0x5.5p+2", "-0xa.ap+1" }
 135     },
 136   };
 137
 138 static int
 139 test_hex_in_one_mode (double d, const char *fmt, const char *const expected[4],
 140                       const char *mode_name)
 141 {
 142   char buf[100];
 143   int ret = snprintf (buf, sizeof buf, fmt, d);
 144   if (ret <= 0 || ret >= (int) sizeof buf)
 145     {
 146       printf ("snprintf for %a returned %d\n", d, ret);
 147       return 1;
 148     }
 149   if (strcmp (buf, expected[0]) == 0
 150       || strcmp (buf, expected[1]) == 0
 151       || strcmp (buf, expected[2]) == 0
 152       || strcmp (buf, expected[3]) == 0)
 153     return 0;
 154   else
 155     {
 156       printf ("snprintf (\"%s\", %a) returned \"%s\" not "
 157               "\"%s\" or \"%s\" or \"%s\" or \"%s\" (%s)\n",
 158               fmt, d, buf, expected[0], expected[1], expected[2], expected[3],
 159               mode_name);
 160       return 1;
 161     }
 162 }
 163
 164 static int
 165 do_test (void)
 166 {
 167   int save_round_mode __attribute__ ((unused)) = fegetround ();
 168   int result = 0;
 169
 170   for (size_t i = 0; i < sizeof (dec_tests) / sizeof (dec_tests[0]); i++)
 171     {
 172       result |= test_dec_in_one_mode (dec_tests[i].d, dec_tests[i].fmt,
 173                                       dec_tests[i].rn, "default rounding mode");
 174 #ifdef FE_DOWNWARD
 175       if (!fesetround (FE_DOWNWARD))
 176         {
 177           result |= test_dec_in_one_mode (dec_tests[i].d, dec_tests[i].fmt,
 178                                           dec_tests[i].rd, "FE_DOWNWARD");
 179           fesetround (save_round_mode);
 180         }
 181 #endif
 182 #ifdef FE_TOWARDZERO
 183       if (!fesetround (FE_TOWARDZERO))
 184         {
 185           result |= test_dec_in_one_mode (dec_tests[i].d, dec_tests[i].fmt,
 186                                           dec_tests[i].rz, "FE_TOWARDZERO");
 187           fesetround (save_round_mode);
 188         }
 189 #endif
 190 #ifdef FE_UPWARD
 191       if (!fesetround (FE_UPWARD))
 192         {
 193           result |= test_dec_in_one_mode (dec_tests[i].d, dec_tests[i].fmt,
 194                                           dec_tests[i].ru, "FE_UPWARD");
 195           fesetround (save_round_mode);
 196         }
 197 #endif
 198     }
 199
 200   for (size_t i = 0; i < sizeof (hex_tests) / sizeof (hex_tests[0]); i++)
 201     {
 202       result |= test_hex_in_one_mode (hex_tests[i].d, hex_tests[i].fmt,
 203                                       hex_tests[i].rn, "default rounding mode");
 204 #ifdef FE_DOWNWARD
 205       if (!fesetround (FE_DOWNWARD))
 206         {
 207           result |= test_hex_in_one_mode (hex_tests[i].d, hex_tests[i].fmt,
 208                                           hex_tests[i].rd, "FE_DOWNWARD");
 209           fesetround (save_round_mode);
 210         }
 211 #endif
 212 #ifdef FE_TOWARDZERO
 213       if (!fesetround (FE_TOWARDZERO))
 214         {
 215           result |= test_hex_in_one_mode (hex_tests[i].d, hex_tests[i].fmt,
 216                                           hex_tests[i].rz, "FE_TOWARDZERO");
 217           fesetround (save_round_mode);
 218         }
 219 #endif
 220 #ifdef FE_UPWARD
 221       if (!fesetround (FE_UPWARD))
 222         {
 223           result |= test_hex_in_one_mode (hex_tests[i].d, hex_tests[i].fmt,
 224                                           hex_tests[i].ru, "FE_UPWARD");
 225           fesetround (save_round_mode);
 226         }
 227 #endif
 228     }
 229
 230   return result;
 231 }
 232
 233 #define TEST_FUNCTION do_test ()
 234 #include "../test-skeleton.c"