cppcheck/lib/checkpostfixoperator.cpp

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/*
* Cppcheck - A tool for static C/C++ code analysis
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* Copyright (C) 2007-2012 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"
#include "symboldatabase.h"
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//---------------------------------------------------------------------------
// Register this check class (by creating a static instance of it)
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namespace {
CheckPostfixOperator instance;
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}
void CheckPostfixOperator::postfixOperator()
{
if (!_settings->isEnabled("performance"))
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return;
const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase();
const std::size_t functions = symbolDatabase->functionScopes.size();
for (std::size_t i = 0; i < functions; ++i) {
const Scope * scope = symbolDatabase->functionScopes[i];
for (const Token* tok = scope->classStart->next(); tok != scope->classEnd; tok = tok->next()) {
if (tok->type() == Token::eIncDecOp) {
bool result = false;
if (Token::Match(tok->tokAt(-2), ";|{|}") && Token::Match(tok->next(), ";|)|,")) {
result = true;
} else if (tok->strAt(-2) == ",") {
int ii(1);
while (tok->strAt(ii) != ")" && tok->tokAt(ii) != 0) {
if (tok->strAt(ii) == ";") {
result = true;
break;
}
++ii;
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}
} else if (tok->strAt(-2) == "<<" && tok->strAt(1) == "<<") {
result = true;
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}
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if (result && tok->previous()->varId()) {
const Variable *var = symbolDatabase->getVariableFromVarId(tok->previous()->varId());
if (!var || var->isPointer() || var->isArray() || var->isReference())
continue;
const Token *decltok = var->nameToken();
if (Token::Match(decltok->previous(), "iterator|const_iterator|reverse_iterator|const_reverse_iterator")) {
// the variable is an iterator
postfixOperatorError(tok);
} else if (var->type()) {
// 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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}