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/*
* Cppcheck - A tool for static C/C++ code analysis
* Copyright (C) 2007-2012 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 assignment / condition mismatches
//---------------------------------------------------------------------------
#include "checkassignif.h"
#include "symboldatabase.h"
//---------------------------------------------------------------------------
// Register this check class (by creating a static instance of it)
namespace {
CheckAssignIf instance;
}
void CheckAssignIf::assignIf()
{
if (!_settings->isEnabled("style"))
return;
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
if (tok->str() != "=")
continue;
if (Token::Match(tok->tokAt(-2), "[;{}] %var% = %var% [&|] %num% ;")) {
const unsigned int varid(tok->previous()->varId());
if (varid == 0)
continue;
const char bitop(tok->strAt(2).at(0));
const MathLib::bigint num = MathLib::toLongNumber(tok->strAt(3));
if (num < 0)
continue;
for (const Token *tok2 = tok->tokAt(4); tok2; tok2 = tok2->next()) {
if (tok2->str() == "(" || tok2->str() == "}" || tok2->str() == "=")
break;
if (Token::Match(tok2, "if|while|for (")) {
// parse condition
const Token * const end = tok2->next()->link();
for (; tok2 != end; tok2 = tok2->next()) {
if (Token::Match(tok2, "[(,] &| %varid% [,)]", varid))
break;
if (Token::Match(tok2,"&&|%oror%|( %varid% %any% %num% &&|%oror%|)", varid)) {
const Token *vartok = tok2->next();
const std::string& op(vartok->strAt(1));
const MathLib::bigint num2 = MathLib::toLongNumber(vartok->strAt(2));
const std::string condition(vartok->str() + op + vartok->strAt(2));
if (op == "==" && (num & num2) != ((bitop=='&') ? num2 : num))
assignIfError(tok, tok2, condition, false);
else if (op == "!=" && (num & num2) != ((bitop=='&') ? num2 : num))
assignIfError(tok, tok2, condition, true);
}
}
}
}
}
}
}
void CheckAssignIf::assignIfError(const Token *tok1, const Token *tok2, const std::string &condition, bool result)
{
std::list<const Token *> locations;
locations.push_back(tok1);
locations.push_back(tok2);
reportError(locations,
Severity::style,
"assignIfError",
"Mismatching assignment and comparison, comparison '" + condition + "' is always " + std::string(result ? "true" : "false") + ".");
}
void CheckAssignIf::comparison()
{
if (!_settings->isEnabled("style"))
return;
for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
if (Token::Match(tok, "&|%or% %num% )| ==|!= %num% &&|%oror%|)")) {
const MathLib::bigint num1 = MathLib::toLongNumber(tok->strAt(1));
if (num1 < 0)
continue;
const Token *compareToken = tok->tokAt(2);
if (compareToken->str() == ")") {
if (!Token::Match(compareToken->link()->previous(), "(|%oror%|&&"))
continue;
compareToken = compareToken->next();
}
const MathLib::bigint num2 = MathLib::toLongNumber(compareToken->strAt(1));
if (num2 < 0)
continue;
if ((tok->str() == "&" && (num1 & num2) != num2) ||
(tok->str() == "|" && (num1 | num2) != num2)) {
const std::string& op(compareToken->str());
comparisonError(tok, tok->str(), num1, op, num2, op=="==" ? false : true);
}
}
}
}
void CheckAssignIf::comparisonError(const Token *tok, const std::string &bitop, MathLib::bigint value1, const std::string &op, MathLib::bigint value2, bool result)
{
std::ostringstream expression;
expression << std::hex << "(X " << bitop << " 0x" << value1 << ") " << op << " 0x" << value2;
const std::string errmsg("Expression '" + expression.str() + "' is always " + (result?"true":"false") + ".\n"
"The expression '" + expression.str() + "' is always " + (result?"true":"false") +
". Check carefully constants and operators used, these errors might be hard to "
"spot sometimes. In case of complex expression it might help to split it to "
"separate expressions.");
reportError(tok, Severity::style, "comparisonError", errmsg);
}
void CheckAssignIf::multiCondition()
{
if (!_settings->isEnabled("style"))
return;
const SymbolDatabase* const symbolDatabase = _tokenizer->getSymbolDatabase();
for (std::list<Scope>::const_iterator i = symbolDatabase->scopeList.begin(); i != symbolDatabase->scopeList.end(); ++i) {
if (i->type == Scope::eIf && Token::Match(i->classDef, "if ( %var% & %num% ) {")) {
const Token* const tok = i->classDef;
const unsigned int varid(tok->tokAt(2)->varId());
if (varid == 0)
continue;
const MathLib::bigint num1 = MathLib::toLongNumber(tok->strAt(4));
if (num1 < 0)
continue;
const Token *tok2 = tok->linkAt(6);
while (Token::simpleMatch(tok2, "} else { if (")) {
// Goto '('
const Token * const opar = tok2->tokAt(4);
// tok2: skip if-block
tok2 = opar->link();
if (Token::simpleMatch(tok2, ") {"))
tok2 = tok2->next()->link();
// check condition..
if (Token::Match(opar, "( %varid% ==|& %num% &&|%oror%|)", varid)) {
const MathLib::bigint num2 = MathLib::toLongNumber(opar->strAt(3));
if (num2 < 0)
continue;
if ((num1 & num2) == num2) {
multiConditionError(opar, tok->linenr());
}
}
}
}
}
}
void CheckAssignIf::multiConditionError(const Token *tok, unsigned int line1)
{
std::ostringstream errmsg;
errmsg << "Expression is always false because 'else if' condition matches previous condition at line "
<< line1 << ".";
reportError(tok, Severity::style, "multiCondition", errmsg.str());
}
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