Line data    Source code

       1             : // Copyright (c) 2021-2023  Made to Order Software Corp.  All Rights Reserved
       2             : //
       3             : // https://snapwebsites.org/project/snapdev
       4             : // contact@m2osw.com
       5             : //
       6             : // This program is free software: you can redistribute it and/or modify
       7             : // it under the terms of the GNU General Public License as published by
       8             : // the Free Software Foundation, either version 3 of the License, or
       9             : // (at your option) any later version.
      10             : //
      11             : // This program is distributed in the hope that it will be useful,
      12             : // but WITHOUT ANY WARRANTY; without even the implied warranty of
      13             : // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      14             : // GNU General Public License for more details.
      15             : //
      16             : // You should have received a copy of the GNU General Public License
      17             : // along with this program.  If not, see <https://www.gnu.org/licenses/>.
      18             : 
      19             : /** \file
      20             :  * \brief Verify the saturated_add() functions.
      21             :  *
      22             :  * This file implements tests to verify that the saturated_add() functions
      23             :  * will indeed saturate the result on an overflow.
      24             :  */
      25             : 
      26             : // self
      27             : //
      28             : #include    "catch_main.h"
      29             : 
      30             : 
      31             : 
      32             : // snapdev
      33             : //
      34             : #include    <snapdev/math.h>
      35             : #include    <snapdev/ostream_int128.h>
      36             : 
      37             : 
      38             : // last include
      39             : //
      40             : #include    <snapdev/poison.h>
      41             : 
      42             : 
      43             : // __int128 is not ISO C++ yet
      44             : #pragma GCC diagnostic ignored "-Wpedantic"
      45             : 
      46             : 
      47           5 : CATCH_TEST_CASE("saturated_add_uint", "[math]")
      48             : {
      49           5 :     CATCH_START_SECTION("saturated_add_uint8: test all possible cases with 8 bits")
      50             :     {
      51         257 :         for(std::uint32_t n(0); n < 256; ++n)
      52             :         {
      53       65792 :             for(std::uint32_t m(0); m < 256; ++m)
      54             :             {
      55       65536 :                 std::uint32_t expected(n + m);
      56       65536 :                 if(expected > 255)      // easy to test in this case
      57             :                 {
      58       32640 :                     expected = 255;
      59             :                 }
      60       65536 :                 std::uint32_t const result(snapdev::saturated_add(
      61             :                               static_cast<std::uint8_t>(n)
      62       65536 :                             , static_cast<std::uint8_t>(m)));
      63       65536 :                 CATCH_REQUIRE(result == expected);
      64             :             }
      65             :         }
      66             :     }
      67           5 :     CATCH_END_SECTION()
      68             : 
      69           5 :     CATCH_START_SECTION("saturated_add_uint16: test many possible cases with 16 bits")
      70             :     {
      71        1339 :         for(std::uint32_t n(0); n < 65536; n += rand() % 100)
      72             :         {
      73     1772451 :             for(std::uint32_t m(0); m < 65536; m += rand() % 100)
      74             :             {
      75     1771113 :                 std::uint32_t expected(n + m);
      76     1771113 :                 if(expected > 65535)      // easy to test in this case
      77             :                 {
      78      883923 :                     expected = 65535;
      79             :                 }
      80     1771113 :                 std::uint32_t const result(snapdev::saturated_add(
      81             :                               static_cast<std::uint16_t>(n)
      82     1771113 :                             , static_cast<std::uint16_t>(m)));
      83     1771113 :                 CATCH_REQUIRE(result == expected);
      84             :             }
      85             :         }
      86             :     }
      87           5 :     CATCH_END_SECTION()
      88             : 
      89           5 :     CATCH_START_SECTION("saturated_add_uint32: test a few possible cases with 32 bits")
      90             :     {
      91             :         // no overflow at all
      92             :         {
      93           1 :             std::uint32_t const result(snapdev::saturated_add(
      94             :                           static_cast<std::uint32_t>(1'000)
      95             :                         , static_cast<std::uint32_t>(32'000)));
      96           1 :             CATCH_REQUIRE(result == 33'000);
      97             :         }
      98             : 
      99             :         // no overflow, but close
     100             :         {
     101           1 :             std::uint32_t const result(snapdev::saturated_add(
     102             :                           static_cast<std::uint32_t>(1'000)
     103           1 :                         , std::numeric_limits<std::uint32_t>::max() - 1'000));
     104           1 :             CATCH_REQUIRE(result == std::numeric_limits<std::uint32_t>::max());
     105             :         }
     106             : 
     107             :         // overflow by 1
     108             :         {
     109           1 :             std::uint32_t const result(snapdev::saturated_add(
     110             :                           static_cast<std::uint32_t>(1'001)
     111           1 :                         , std::numeric_limits<std::uint32_t>::max() - 1'000));
     112           1 :             CATCH_REQUIRE(result == std::numeric_limits<std::uint32_t>::max());
     113             :         }
     114             : 
     115             :         // definitive overflow
     116             :         {
     117           1 :             std::uint32_t const result(snapdev::saturated_add(
     118             :                           static_cast<std::uint32_t>(3'501)
     119           1 :                         , std::numeric_limits<std::uint32_t>::max() - 1'000));
     120           1 :             CATCH_REQUIRE(result == std::numeric_limits<std::uint32_t>::max());
     121             :         }
     122             : 
     123             :         // max. overflow
     124             :         {
     125           1 :             std::uint32_t const result(snapdev::saturated_add(
     126             :                           std::numeric_limits<std::uint32_t>::max()
     127             :                         , std::numeric_limits<std::uint32_t>::max()));
     128           1 :             CATCH_REQUIRE(result == std::numeric_limits<std::uint32_t>::max());
     129             :         }
     130             :     }
     131           5 :     CATCH_END_SECTION()
     132             : 
     133           5 :     CATCH_START_SECTION("saturated_add_uint64: test a few possible cases with 64 bits")
     134             :     {
     135             :         // no overflow at all
     136             :         {
     137           1 :             std::uint64_t const result(snapdev::saturated_add(
     138             :                           static_cast<std::uint64_t>(1'000)
     139             :                         , static_cast<std::uint64_t>(32'000)));
     140           1 :             CATCH_REQUIRE(result == 33'000);
     141             :         }
     142             : 
     143             :         // no overflow, but close
     144             :         {
     145           1 :             std::uint64_t const result(snapdev::saturated_add(
     146             :                           static_cast<std::uint64_t>(1'000)
     147           1 :                         , std::numeric_limits<std::uint64_t>::max() - 1'000));
     148           1 :             CATCH_REQUIRE(result == std::numeric_limits<std::uint64_t>::max());
     149             :         }
     150             : 
     151             :         // overflow by 1
     152             :         {
     153           1 :             std::uint64_t const result(snapdev::saturated_add(
     154             :                           static_cast<std::uint64_t>(1'001)
     155           1 :                         , std::numeric_limits<std::uint64_t>::max() - 1'000));
     156           1 :             CATCH_REQUIRE(result == std::numeric_limits<std::uint64_t>::max());
     157             :         }
     158             : 
     159             :         // definitive overflow
     160             :         {
     161           1 :             std::uint64_t const result(snapdev::saturated_add(
     162             :                           static_cast<std::uint64_t>(3'501)
     163           1 :                         , std::numeric_limits<std::uint64_t>::max() - 1'000));
     164           1 :             CATCH_REQUIRE(result == std::numeric_limits<std::uint64_t>::max());
     165             :         }
     166             : 
     167             :         // max. overflow
     168             :         {
     169           1 :             std::uint64_t const result(snapdev::saturated_add(
     170             :                           std::numeric_limits<std::uint64_t>::max()
     171             :                         , std::numeric_limits<std::uint64_t>::max()));
     172           1 :             CATCH_REQUIRE(result == std::numeric_limits<std::uint64_t>::max());
     173             :         }
     174             :     }
     175           5 :     CATCH_END_SECTION()
     176             : 
     177           5 :     CATCH_START_SECTION("saturated_add_uint128: test a few possible cases with 128 bits")
     178             :     {
     179             : #pragma GCC diagnostic push
     180             : #pragma GCC diagnostic ignored "-Wpedantic"
     181             :         // no overflow at all
     182             :         {
     183           1 :             unsigned __int128 const result(snapdev::saturated_add(
     184             :                           static_cast<unsigned __int128>(1'000)
     185             :                         , static_cast<unsigned __int128>(32'000)));
     186           1 :             CATCH_REQUIRE(result == 33'000);
     187             :         }
     188             : 
     189             :         // no overflow, but close
     190             :         {
     191           1 :             unsigned __int128 const result(snapdev::saturated_add(
     192             :                           static_cast<unsigned __int128>(1'000)
     193           1 :                         , std::numeric_limits<unsigned __int128>::max() - 1'000));
     194           1 :             CATCH_REQUIRE(result == std::numeric_limits<unsigned __int128>::max());
     195             :         }
     196             : 
     197             :         // overflow by 1
     198             :         {
     199           1 :             unsigned __int128 const result(snapdev::saturated_add(
     200             :                           static_cast<unsigned __int128>(1'001)
     201           1 :                         , std::numeric_limits<unsigned __int128>::max() - 1'000));
     202           1 :             CATCH_REQUIRE(result == std::numeric_limits<unsigned __int128>::max());
     203             :         }
     204             : 
     205             :         // definitive overflow
     206             :         {
     207           1 :             unsigned __int128 const result(snapdev::saturated_add(
     208             :                           static_cast<unsigned __int128>(3'501)
     209           1 :                         , std::numeric_limits<unsigned __int128>::max() - 1'000));
     210           1 :             CATCH_REQUIRE(result == std::numeric_limits<unsigned __int128>::max());
     211             :         }
     212             : 
     213             :         // max. overflow
     214             :         {
     215           1 :             unsigned __int128 const result(snapdev::saturated_add(
     216             :                           std::numeric_limits<unsigned __int128>::max()
     217             :                         , std::numeric_limits<unsigned __int128>::max()));
     218           1 :             CATCH_REQUIRE(result == std::numeric_limits<unsigned __int128>::max());
     219             :         }
     220             : #pragma GCC diagnostic pop
     221             :     }
     222           5 :     CATCH_END_SECTION()
     223           5 : }
     224             : 
     225             : 
     226           5 : CATCH_TEST_CASE("saturated_add_int", "[math]")
     227             : {
     228           5 :     CATCH_START_SECTION("saturated_add_int8: test all possible cases with 8 bits")
     229             :     {
     230         257 :         for(std::int32_t n(-128); n < 128; ++n)
     231             :         {
     232       65792 :             for(std::int32_t m(-128); m < 128; ++m)
     233             :             {
     234       65536 :                 std::int32_t expected(n + m);
     235       65536 :                 if(expected < -128)
     236             :                 {
     237        8256 :                     expected = -128;
     238             :                 }
     239       57280 :                 else if(expected > 127)
     240             :                 {
     241        8128 :                     expected = 127;
     242             :                 }
     243       65536 :                 std::int32_t const result(snapdev::saturated_add(
     244             :                               static_cast<std::int8_t>(n)
     245       65536 :                             , static_cast<std::int8_t>(m)));
     246       65536 :                 CATCH_REQUIRE(result == expected);
     247             :             }
     248             :         }
     249             :     }
     250           5 :     CATCH_END_SECTION()
     251             : 
     252           5 :     CATCH_START_SECTION("saturated_add_int16: test many possible cases with 16 bits")
     253             :     {
     254        1299 :         for(std::int32_t n(-32768); n < 32768; n += rand() % 100)
     255             :         {
     256     1721242 :             for(std::int32_t m(-32768); m < 32768; m += rand() % 100)
     257             :             {
     258     1719944 :                 std::int32_t expected(n + m);
     259     1719944 :                 if(expected < -32768)
     260             :                 {
     261      212298 :                     expected = -32768;
     262             :                 }
     263     1507646 :                 else if(expected > 32767)
     264             :                 {
     265      220209 :                     expected = 32767;
     266             :                 }
     267     1719944 :                 std::int32_t const result(snapdev::saturated_add(
     268             :                               static_cast<std::int16_t>(n)
     269     1719944 :                             , static_cast<std::int16_t>(m)));
     270     1719944 :                 CATCH_REQUIRE(result == expected);
     271             :             }
     272             :         }
     273             :     }
     274           5 :     CATCH_END_SECTION()
     275             : 
     276           5 :     CATCH_START_SECTION("saturated_add_int32: test a few possible cases with 32 bits")
     277             :     {
     278             :         // no overflow at all
     279             :         {
     280           1 :             std::int32_t const result(snapdev::saturated_add(
     281             :                           static_cast<std::int32_t>(1'000)
     282             :                         , static_cast<std::int32_t>(33'000)));
     283           1 :             CATCH_REQUIRE(result == 34'000);
     284             :         }
     285             : 
     286             :         // no overflow, but close
     287             :         {
     288           1 :             std::int32_t const result(snapdev::saturated_add(
     289             :                           static_cast<std::int32_t>(1'000)
     290           1 :                         , std::numeric_limits<std::int32_t>::max() - 1'000));
     291           1 :             CATCH_REQUIRE(result == std::numeric_limits<std::int32_t>::max());
     292             :         }
     293             : 
     294             :         // overflow by 1
     295             :         {
     296           1 :             std::int32_t const result(snapdev::saturated_add(
     297             :                           static_cast<std::int32_t>(1'001)
     298           1 :                         , std::numeric_limits<std::int32_t>::max() - 1'000));
     299           1 :             CATCH_REQUIRE(result == std::numeric_limits<std::int32_t>::max());
     300             :         }
     301             : 
     302             :         // definitive overflow
     303             :         {
     304           1 :             std::int32_t const result(snapdev::saturated_add(
     305             :                           static_cast<std::int32_t>(3'501)
     306           1 :                         , std::numeric_limits<std::int32_t>::max() - 1'000));
     307           1 :             CATCH_REQUIRE(result == std::numeric_limits<std::int32_t>::max());
     308             :         }
     309             : 
     310             :         // max. overflow
     311             :         {
     312           1 :             std::int32_t const result(snapdev::saturated_add(
     313             :                           std::numeric_limits<std::int32_t>::max()
     314             :                         , std::numeric_limits<std::int32_t>::max()));
     315           1 :             CATCH_REQUIRE(result == std::numeric_limits<std::int32_t>::max());
     316             :         }
     317             :     }
     318           5 :     CATCH_END_SECTION()
     319             : 
     320           5 :     CATCH_START_SECTION("saturated_add_int64: test a few possible cases with 64 bits")
     321             :     {
     322             :         // no overflow at all
     323             :         {
     324           1 :             std::int64_t const result(snapdev::saturated_add(
     325             :                           static_cast<std::int64_t>(1'000)
     326             :                         , static_cast<std::int64_t>(32'000)));
     327           1 :             CATCH_REQUIRE(result == 33'000);
     328             :         }
     329             : 
     330             :         // no overflow, but close
     331             :         {
     332           1 :             std::int64_t const result(snapdev::saturated_add(
     333             :                           static_cast<std::int64_t>(1'000)
     334           1 :                         , std::numeric_limits<std::int64_t>::max() - 1'000));
     335           1 :             CATCH_REQUIRE(result == std::numeric_limits<std::int64_t>::max());
     336             :         }
     337             : 
     338             :         // overflow by 1
     339             :         {
     340           1 :             std::int64_t const result(snapdev::saturated_add(
     341             :                           static_cast<std::int64_t>(1'001)
     342           1 :                         , std::numeric_limits<std::int64_t>::max() - 1'000));
     343           1 :             CATCH_REQUIRE(result == std::numeric_limits<std::int64_t>::max());
     344             :         }
     345             : 
     346             :         // definitive overflow
     347             :         {
     348           1 :             std::int64_t const result(snapdev::saturated_add(
     349             :                           static_cast<std::int64_t>(3'501)
     350           1 :                         , std::numeric_limits<std::int64_t>::max() - 1'000));
     351           1 :             CATCH_REQUIRE(result == std::numeric_limits<std::int64_t>::max());
     352             :         }
     353             : 
     354             :         // max. overflow
     355             :         {
     356           1 :             std::int64_t const result(snapdev::saturated_add(
     357             :                           std::numeric_limits<std::int64_t>::max()
     358             :                         , std::numeric_limits<std::int64_t>::max()));
     359           1 :             CATCH_REQUIRE(result == std::numeric_limits<std::int64_t>::max());
     360             :         }
     361             :     }
     362           5 :     CATCH_END_SECTION()
     363             : 
     364           5 :     CATCH_START_SECTION("saturated_add_int128: test a few possible cases with 128 bits")
     365             :     {
     366             : #pragma GCC diagnostic push
     367             : #pragma GCC diagnostic ignored "-Wpedantic"
     368             :         // no overflow at all
     369             :         {
     370           1 :             __int128 const result(snapdev::saturated_add(
     371             :                           static_cast<__int128>(1'000LL)
     372             :                         , static_cast<__int128>(32'000'000LL)));
     373           1 :             CATCH_REQUIRE(result == 32'001'000LL);
     374             :         }
     375             : 
     376             :         // no overflow, but close
     377             :         {
     378           1 :             __int128 const result(snapdev::saturated_add(
     379             :                           static_cast<__int128>(1'000)
     380           1 :                         , std::numeric_limits<__int128>::max() - 1'000));
     381           1 :             CATCH_REQUIRE(result == std::numeric_limits<__int128>::max());
     382             :         }
     383             : 
     384             :         // overflow by 1
     385             :         {
     386           1 :             __int128 const result(snapdev::saturated_add(
     387             :                           static_cast<__int128>(1'001)
     388           1 :                         , std::numeric_limits<__int128>::max() - 1'000));
     389           1 :             CATCH_REQUIRE(result == std::numeric_limits<__int128>::max());
     390             :         }
     391             : 
     392             :         // definitive overflow
     393             :         {
     394           1 :             __int128 const result(snapdev::saturated_add(
     395             :                           static_cast<__int128>(3'501)
     396           1 :                         , std::numeric_limits<__int128>::max() - 1'000));
     397           1 :             CATCH_REQUIRE(result == std::numeric_limits<__int128>::max());
     398             :         }
     399             : 
     400             :         // max. overflow
     401             :         {
     402           1 :             __int128 const result(snapdev::saturated_add(
     403             :                           std::numeric_limits<__int128>::max()
     404             :                         , std::numeric_limits<__int128>::max()));
     405           1 :             CATCH_REQUIRE(result == std::numeric_limits<__int128>::max());
     406             :         }
     407             : #pragma GCC diagnostic pop
     408             :     }
     409           5 :     CATCH_END_SECTION()
     410           5 : }
     411             : 
     412             : 
     413             : // vim: ts=4 sw=4 et