cppcheck/lib/checkpostfixoperator.cpp

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/*
* Cppcheck - A tool for static C/C++ code analysis
* Copyright (C) 2007-2011 Daniel Marjamäki and Cppcheck team.
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*
* 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/>.
*/
//---------------------------------------------------------------------------
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// You should use ++ and -- as prefix whenever possible as these are more
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// efficient than postfix operators
//---------------------------------------------------------------------------
#include "checkpostfixoperator.h"
//---------------------------------------------------------------------------
// Register this check class (by creating a static instance of it)
namespace
{
CheckPostfixOperator instance;
}
void CheckPostfixOperator::postfixOperator()
{
if (!_settings->_checkCodingStyle)
return;
const Token *tok = _tokenizer->tokens();
// prevent crash if first token is ++ or --
if (Token::Match(tok, "++|--"))
tok = tok->next();
for (; tok; tok = tok->next())
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{
bool result = false;
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if (Token::Match(tok, "++|--"))
{
if (Token::Match(tok->previous()->previous(), ";|{|}") && Token::Match(tok->next(), ";|)|,"))
{
result = true;
}
else if (tok->strAt(-2) == ",")
{
int i(1);
while (tok->strAt(i) != ")")
{
if (tok->strAt(i) == ";")
{
result = true;
break;
}
++i;
}
}
else if (tok->strAt(-2) == "<<" && tok->strAt(1) == "<<")
{
result = true;
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}
}
if (result && tok->previous()->varId())
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{
const Token *decltok = Token::findmatch(_tokenizer->tokens(), "%varid%", tok->previous()->varId());
if (!Token::Match(decltok->tokAt(-1), "%type%"))
continue;
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if (decltok && Token::Match(decltok->previous(), "iterator|const_iterator|reverse_iterator|const_reverse_iterator"))
{
// the variable is an iterator
postfixOperatorError(tok);
}
else
{
const std::string classDef = std::string("class ") + std::string(decltok->previous()->strAt(0));
if (Token::findmatch(_tokenizer->tokens(), classDef.c_str()))
{
// the variable is an instance of class
postfixOperatorError(tok);
}
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}
}
}
}
//---------------------------------------------------------------------------
void CheckPostfixOperator::postfixOperatorError(const Token *tok)
{
reportError(tok, Severity::performance, "postfixOperator",
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"Prefer prefix ++/-- operators for non-primitive types.\n"
"Prefix ++/-- operators should be preferred for non-primitive types. "
"Pre-increment/decrement can be more efficient than "
"post-increment/decrement. Post-increment/decrement usually "
"involves keeping a copy of the previous value around and "
"adds a little extra code.");
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}