cppcheck/testdivision.cpp

/*
 * c++check - c/c++ syntax checking
 * Copyright (C) 2007 Daniel Marjamäki
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/
 */


// Check for dangerous division..
// such as "svar / uvar". Treating "svar" as unsigned data is not good


#define UNIT_TESTING
#include "tokenize.h"
#include "checkother.h"
#include "testsuite.h"

#include <sstream>

extern std::ostringstream errout;

class TestDivision : public TestFixture
{
public:
    TestDivision() : TestFixture("TestDivision")
    { }

private:
    void check( const char code[] )
    {
        // Tokenize..
        Tokenizer tokenizer;
        std::istringstream istr(code);
        tokenizer.tokenize( istr, "test.cpp" );

        // Clear the error buffer..
        errout.str("");

        // Check for unsigned divisions..
        CheckOther checkOther( &tokenizer, this );
        checkOther.CheckUnsignedDivision();
    }

    void run()
    {
        TEST_CASE( division1 );
        TEST_CASE( division2 );
        TEST_CASE( division3 );
        TEST_CASE( division4 );
        TEST_CASE( division5 );
        TEST_CASE( division6 );
        TEST_CASE( division7 );
    }

    void division1()
    {
        check( "void f()\n"
               "{\n"
               "    int ivar = -2;\n"
               "    unsigned int uvar = 2;\n"
               "    return ivar / uvar;\n"
               "}\n" );
        ASSERT_EQUALS( std::string("[test.cpp:5]: Warning: Division with signed and unsigned operators\n"), errout.str() );
    }

    void division2()
    {
        check( "void f()\n"
               "{\n"
               "    int ivar = -2;\n"
               "    unsigned int uvar = 2;\n"
               "    return uvar / ivar;\n"
               "}\n" );
        ASSERT_EQUALS( std::string("[test.cpp:5]: Warning: Division with signed and unsigned operators\n"), errout.str() );
    }

    void division3()
    {
        check( "typedef int s32;\n"
               "typedef unsigned int u32;\n"
               "void f()\n"
               "{\n"
               "    s32 ivar = -2;\n"
               "    u32 uvar = 2;\n"
               "    return uvar / ivar;\n"
               "}\n" );
        ASSERT_EQUALS( std::string("[test.cpp:7]: Warning: Division with signed and unsigned operators\n"), errout.str() );
    }

    void division4()
    {
        check( "void f1()\n"
               "{\n"
               "    int i1;\n"
               "}\n"
               "\n"
               "void f2(unsigned int i1)\n"
               "{\n"
               "    unsigned int i2;\n"
               "    result = i2 / i1;\n"
               );
        ASSERT_EQUALS( std::string(""), errout.str() );
    }

    void division5()
    {
        check( "#define USER_HASH (16)\n"
               "void foo()\n"
               "{\n"
               "    unsigned int val = 32;\n"
               "    val = val / USER_HASH;\n"
               );
        ASSERT_EQUALS( std::string(""), errout.str() );
    }

    void division6()
    {
        check( "void foo()\n"
               "{\n"
               "    unsigned int val = 32;\n"
               "    int i = val / -2;\n"
               );
        ASSERT_EQUALS( std::string("[test.cpp:4]: Unsigned division. The result will be wrong.\n"), errout.str() );
    }

    void division7()
    {
        check( "void foo()\n"
               "{\n"
               "    unsigned int val = 32;\n"
               "    int i = -96 / val;\n"
               );
        ASSERT_EQUALS( std::string("[test.cpp:4]: Unsigned division. The result will be wrong.\n"), errout.str() );
    }
};

REGISTER_TEST( TestDivision )