cppcheck/test/testdivision.cpp

/*
 * Cppcheck - A tool for static C/C++ code analysis
 * Copyright (C) 2007-2009 Daniel Marjamäki and Cppcheck team.
 *
 * 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


#include "../src/tokenize.h"
#include "../src/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[], bool style = true, bool all = true)
    {
        // Tokenize..
        Tokenizer tokenizer;
        std::istringstream istr(code);
        tokenizer.tokenize(istr, "test.cpp");

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

        Settings settings;
        settings._showAll = all;
        settings._checkCodingStyle = style;

        // Check for unsigned divisions..
        CheckOther checkOther(&tokenizer, &settings, 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);
        TEST_CASE(division8);
    }

    void division1()
    {
        check("void f()\n"
              "{\n"
              "    int ivar = -2;\n"
              "    unsigned int uvar = 2;\n"
              "    return ivar / uvar;\n"
              "}\n");
        ASSERT_EQUALS("[test.cpp:5]: (possible style) 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("[test.cpp:5]: (possible style) 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("[test.cpp:7]: (possible style) 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("", 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("", errout.str());
    }

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

    void division8()
    {
        check("void foo(int b)\n"
              "{\n"
              "    if (b > 0)\n"
              "    {\n"
              "         unsigned int a;\n"
              "         unsigned int c = a / b;\n"
              "    }\n"
              "}\n", false, true);
        ASSERT_EQUALS("", errout.str());

        check("void foo(int b)\n"
              "{\n"
              "    if (b > 0)\n"
              "    {\n"
              "         unsigned int a;\n"
              "         unsigned int c = a / b;\n"
              "    }\n"
              "}\n", true, false);
        ASSERT_EQUALS("", errout.str());

        check("void foo(int b)\n"
              "{\n"
              "    if (b > 0)\n"
              "    {\n"
              "         unsigned int a;\n"
              "         unsigned int c = a / b;\n"
              "    }\n"
              "}\n", true, true);
        ASSERT_EQUALS("[test.cpp:6]: (possible style) Division with signed and unsigned operators\n", errout.str());

        check("void a(int i) { }\n"
              "int foo( unsigned int sz )\n"
              "{\n"
              "    register unsigned int i=1;\n"
              "    return i/sz;\n"
              "}\n", true, true);
        ASSERT_EQUALS("", errout.str());
    }
};

REGISTER_TEST(TestDivision)