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Buffer overrun: broke out duplicate code

This commit is contained in:
Daniel Marjamäki 2011-04-04 17:33:43 +02:00
parent eac3a8c86c
commit 0d3874693a
1 changed files with 29 additions and 35 deletions
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64
lib/checkbufferoverrun.cpp
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@ -329,6 +329,31 @@ static bool for_condition(const Token * const tok2, unsigned int varid, std::str
/**
* calculate maximum value of loop variable
* @param stepvalue token that contains the step value
* @param min_value the minimum value of loop variable
* @param max_value maximum value of the loop variable
*/
static bool for_maxvalue(const Token * const stepvalue, const std::string &min_value, std::string &max_value)
{
if (!MathLib::isInt(stepvalue->str()))
return false;
// We have for example code: "for(i=2;i<22;i+=6)
// We can calculate that max value for i is 20, not 21
// 21-2 = 19
// 19/6 = 3
// 6*3+2 = 20
const MathLib::bigint num = MathLib::toLongNumber(stepvalue->str());
MathLib::bigint max = MathLib::toLongNumber(max_value);
const MathLib::bigint min = MathLib::toLongNumber(min_value);
max = ((max - min) / num) * num + min;
max_value = MathLib::toString<MathLib::bigint>(max);
return true;
}
/** /**
* Parse the third sub-statement in for head * Parse the third sub-statement in for head
* \param tok first token * \param tok first token
@ -347,55 +372,24 @@ static bool for3(const Token * const tok,
if (Token::Match(tok, "%varid% += %num% )", varid) || if (Token::Match(tok, "%varid% += %num% )", varid) ||
Token::Match(tok, "%varid% = %num% + %varid% )", varid)) Token::Match(tok, "%varid% = %num% + %varid% )", varid))
{ {
if (!MathLib::isInt(tok->strAt(2))) if (!for_maxvalue(tok->tokAt(2), min_value, max_value))
return false; return false;
const MathLib::bigint num = MathLib::toLongNumber(tok->strAt(2));
// We have for example code: "for(i=2;i<22;i+=6)
// We can calculate that max value for i is 20, not 21
// 21-2 = 19
// 19/6 = 3
// 6*3+2 = 20
MathLib::bigint max = MathLib::toLongNumber(max_value);
MathLib::bigint min = MathLib::toLongNumber(min_value);
max = ((max - min) / num) * num + min;
max_value = MathLib::toString<MathLib::bigint>(max);
} }
else if (Token::Match(tok, "%varid% = %varid% + %num% )", varid)) else if (Token::Match(tok, "%varid% = %varid% + %num% )", varid))
{ {
if (!MathLib::isInt(tok->strAt(4))) if (!for_maxvalue(tok->tokAt(4), min_value, max_value))
return false; return false;
const MathLib::bigint num = MathLib::toLongNumber(tok->strAt(4));
MathLib::bigint max = MathLib::toLongNumber(max_value);
MathLib::bigint min = MathLib::toLongNumber(min_value);
max = ((max - min) / num) * num + min;
max_value = MathLib::toString<MathLib::bigint>(max);
} }
else if (Token::Match(tok, "%varid% -= %num% )", varid) || else if (Token::Match(tok, "%varid% -= %num% )", varid) ||
Token::Match(tok, "%varid% = %num% - %varid% )", varid)) Token::Match(tok, "%varid% = %num% - %varid% )", varid))
{ {
if (!MathLib::isInt(tok->strAt(2))) if (!for_maxvalue(tok->tokAt(2), min_value, max_value))
return false; return false;
const MathLib::bigint num = MathLib::toLongNumber(tok->strAt(2));
MathLib::bigint max = MathLib::toLongNumber(max_value);
MathLib::bigint min = MathLib::toLongNumber(min_value);
max = ((max - min) / num) * num + min;
max_value = MathLib::toString<MathLib::bigint>(max);
} }
else if (Token::Match(tok, "%varid% = %varid% - %num% )", varid)) else if (Token::Match(tok, "%varid% = %varid% - %num% )", varid))
{ {
if (!MathLib::isInt(tok->strAt(4))) if (!for_maxvalue(tok->tokAt(4), min_value, max_value))
return false; return false;
const MathLib::bigint num = MathLib::toLongNumber(tok->strAt(4));
MathLib::bigint max = MathLib::toLongNumber(max_value);
MathLib::bigint min = MathLib::toLongNumber(min_value);
max = ((max - min) / num) * num + min;
max_value = MathLib::toString<MathLib::bigint>(max);
} }
else if (Token::Match(tok, "--| %varid% --| )", varid)) else if (Token::Match(tok, "--| %varid% --| )", varid))
{ {