465 lines
16 KiB
C++
465 lines
16 KiB
C++
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#include "programmemory.h"
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#include "token.h"
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#include "astutils.h"
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#include "symboldatabase.h"
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#include <cassert>
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void ProgramMemory::setValue(nonneg int varid, const ValueFlow::Value &value)
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{
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values[varid] = value;
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}
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bool ProgramMemory::getIntValue(nonneg int varid, MathLib::bigint* result) const
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{
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const std::map<int, ValueFlow::Value>::const_iterator it = values.find(varid);
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const bool found = it != values.end() && it->second.isIntValue();
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if (found)
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*result = it->second.intvalue;
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return found;
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}
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void ProgramMemory::setIntValue(nonneg int varid, MathLib::bigint value)
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{
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values[varid] = ValueFlow::Value(value);
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}
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bool ProgramMemory::getTokValue(nonneg int varid, const Token** result) const
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{
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const std::map<int, ValueFlow::Value>::const_iterator it = values.find(varid);
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const bool found = it != values.end() && it->second.isTokValue();
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if (found)
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*result = it->second.tokvalue;
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return found;
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}
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void ProgramMemory::setUnknown(nonneg int varid)
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{
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values[varid].valueType = ValueFlow::Value::ValueType::UNINIT;
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}
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bool ProgramMemory::hasValue(nonneg int varid)
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{
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return values.find(varid) != values.end();
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}
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void ProgramMemory::swap(ProgramMemory &pm)
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{
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values.swap(pm.values);
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}
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void ProgramMemory::clear()
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{
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values.clear();
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}
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bool ProgramMemory::empty() const
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{
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return values.empty();
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}
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void ProgramMemory::replace(const ProgramMemory &pm)
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{
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for (auto&& p:pm.values)
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values[p.first] = p.second;
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}
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void ProgramMemory::insert(const ProgramMemory &pm)
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{
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for (auto&& p:pm.values)
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values.insert(p);
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}
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bool conditionIsFalse(const Token *condition, const ProgramMemory &programMemory)
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{
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if (!condition)
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return false;
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if (condition->str() == "&&") {
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return conditionIsFalse(condition->astOperand1(), programMemory) ||
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conditionIsFalse(condition->astOperand2(), programMemory);
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}
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ProgramMemory progmem(programMemory);
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MathLib::bigint result = 0;
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bool error = false;
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execute(condition, &progmem, &result, &error);
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return !error && result == 0;
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}
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bool conditionIsTrue(const Token *condition, const ProgramMemory &programMemory)
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{
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if (!condition)
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return false;
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if (condition->str() == "||") {
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return conditionIsTrue(condition->astOperand1(), programMemory) ||
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conditionIsTrue(condition->astOperand2(), programMemory);
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}
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ProgramMemory progmem(programMemory);
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bool error = false;
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MathLib::bigint result = 0;
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execute(condition, &progmem, &result, &error);
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return !error && result == 1;
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}
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static void programMemoryParseCondition(ProgramMemory& pm, const Token* tok, const Token* endTok, const Settings* settings, bool then)
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{
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if (Token::Match(tok, "==|>=|<=|<|>|!=")) {
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if (then && !Token::Match(tok, "==|>=|<="))
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return;
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if (!then && !Token::Match(tok, "<|>|!="))
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return;
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ValueFlow::Value truevalue;
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ValueFlow::Value falsevalue;
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const Token* vartok = parseCompareInt(tok, truevalue, falsevalue);
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if (!vartok)
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return;
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if (vartok->varId() == 0)
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return;
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if (!truevalue.isIntValue())
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return;
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if (isVariableChanged(tok->next(), endTok, vartok->varId(), false, settings, true))
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return;
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pm.setIntValue(vartok->varId(), then ? truevalue.intvalue : falsevalue.intvalue);
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} else if (Token::Match(tok, "%var%")) {
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if (tok->varId() == 0)
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return;
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if (then && !astIsPointer(tok) && !astIsBool(tok))
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return;
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if (isVariableChanged(tok->next(), endTok, tok->varId(), false, settings, true))
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return;
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pm.setIntValue(tok->varId(), then);
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} else if (Token::simpleMatch(tok, "!")) {
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programMemoryParseCondition(pm, tok->astOperand1(), endTok, settings, !then);
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} else if (then && Token::simpleMatch(tok, "&&")) {
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programMemoryParseCondition(pm, tok->astOperand1(), endTok, settings, then);
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programMemoryParseCondition(pm, tok->astOperand2(), endTok, settings, then);
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} else if (!then && Token::simpleMatch(tok, "||")) {
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programMemoryParseCondition(pm, tok->astOperand1(), endTok, settings, then);
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programMemoryParseCondition(pm, tok->astOperand2(), endTok, settings, then);
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}
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}
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static void fillProgramMemoryFromConditions(ProgramMemory& pm, const Scope* scope, const Token* endTok, const Settings* settings)
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{
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if (!scope)
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return;
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if (!scope->isLocal())
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return;
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assert(scope != scope->nestedIn);
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fillProgramMemoryFromConditions(pm, scope->nestedIn, endTok, settings);
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if (scope->type == Scope::eIf || scope->type == Scope::eWhile || scope->type == Scope::eElse) {
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const Token * bodyStart = scope->bodyStart;
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if (scope->type == Scope::eElse) {
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if (!Token::simpleMatch(bodyStart->tokAt(-2), "} else {"))
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return;
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bodyStart = bodyStart->linkAt(-2);
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}
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const Token * condEndTok = bodyStart->previous();
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if (!Token::simpleMatch(condEndTok, ") {"))
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return;
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const Token * condStartTok = condEndTok->link();
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if (!condStartTok)
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return;
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if (!Token::Match(condStartTok->previous(), "if|while ("))
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return;
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const Token * condTok = condStartTok->astOperand2();
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programMemoryParseCondition(pm, condTok, endTok, settings, scope->type != Scope::eElse);
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}
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}
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static void fillProgramMemoryFromConditions(ProgramMemory& pm, const Token* tok, const Settings* settings)
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{
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fillProgramMemoryFromConditions(pm, tok->scope(), tok, settings);
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}
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static void fillProgramMemoryFromConditionalExpression(ProgramMemory& pm, const Token* tok, const Settings* settings)
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{
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const Token* parent = tok->astParent();
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if (Token::Match(parent, "?|&&|%oror%")) {
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programMemoryParseCondition(pm, parent->astOperand1(), tok, settings, !Token::simpleMatch(parent, "||"));
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} else if (Token::simpleMatch(parent, ":") && Token::simpleMatch(parent->astParent(), "?")) {
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programMemoryParseCondition(pm, parent->astParent()->astOperand1(), tok, settings, parent->astOperand1() == tok);
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}
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}
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static void fillProgramMemoryFromAssignments(ProgramMemory& pm, const Token* tok, const ProgramMemory& state, std::unordered_map<nonneg int, ValueFlow::Value> vars)
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{
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int indentlevel = 0;
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for (const Token *tok2 = tok; tok2; tok2 = tok2->previous()) {
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bool setvar = false;
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if (Token::Match(tok2, "[;{}] %var% = %var% ;")) {
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for (auto&& p:vars) {
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if (p.first != tok2->next()->varId())
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continue;
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const Token *vartok = tok2->tokAt(3);
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pm.setValue(vartok->varId(), p.second);
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setvar = true;
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}
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}
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if (!setvar && (Token::Match(tok2, ";|{|}|%type% %var% =") ||
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Token::Match(tok2, "[;{}] const| %type% %var% ("))) {
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const Token *vartok = tok2->next();
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while (vartok->next()->isName())
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vartok = vartok->next();
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if (!pm.hasValue(vartok->varId())) {
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MathLib::bigint result = 0;
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bool error = false;
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execute(vartok->next()->astOperand2(), &pm, &result, &error);
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if (!error)
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pm.setIntValue(vartok->varId(), result);
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else
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pm.setUnknown(vartok->varId());
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}
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}
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if (tok2->str() == "{") {
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if (indentlevel <= 0)
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break;
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--indentlevel;
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}
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if (tok2->str() == "}") {
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const Token *cond = tok2->link();
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cond = Token::simpleMatch(cond->previous(), ") {") ? cond->linkAt(-1) : nullptr;
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if (cond && conditionIsFalse(cond->astOperand2(), state))
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tok2 = cond->previous();
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else if (cond && conditionIsTrue(cond->astOperand2(), state)) {
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++indentlevel;
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continue;
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} else
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break;
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}
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}
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}
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static void removeModifiedVars(ProgramMemory& pm, const Token* tok, const Token* origin)
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{
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for (auto i = pm.values.begin(), last = pm.values.end(); i != last;) {
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if (isVariableChanged(origin, tok, i->first, false, nullptr, true)) {
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i = pm.values.erase(i);
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} else {
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++i;
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}
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}
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}
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static ProgramMemory getInitialProgramState(const Token* tok,
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const Token* origin,
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const std::unordered_map<nonneg int, ValueFlow::Value>& vars = std::unordered_map<nonneg int, ValueFlow::Value> {})
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{
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ProgramMemory pm;
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if (origin) {
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fillProgramMemoryFromConditions(pm, origin, nullptr);
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const ProgramMemory state = pm;
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fillProgramMemoryFromAssignments(pm, tok, state, vars);
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removeModifiedVars(pm, tok, origin);
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}
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return pm;
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}
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ProgramMemory getProgramMemory(const Token *tok, nonneg int varid, const ValueFlow::Value &value)
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{
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ProgramMemory programMemory;
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programMemory.replace(getInitialProgramState(tok, value.tokvalue));
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programMemory.replace(getInitialProgramState(tok, value.condition));
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fillProgramMemoryFromConditions(programMemory, tok, nullptr);
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programMemory.setValue(varid, value);
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if (value.varId)
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programMemory.setIntValue(value.varId, value.varvalue);
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const ProgramMemory state = programMemory;
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fillProgramMemoryFromAssignments(programMemory, tok, state, {{varid, value}});
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return programMemory;
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}
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void execute(const Token *expr,
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ProgramMemory * const programMemory,
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MathLib::bigint *result,
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bool *error)
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{
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if (!expr)
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*error = true;
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else if (expr->hasKnownIntValue()) {
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*result = expr->values().front().intvalue;
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}
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else if (expr->isNumber()) {
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*result = MathLib::toLongNumber(expr->str());
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if (MathLib::isFloat(expr->str()))
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*error = true;
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}
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else if (expr->varId() > 0) {
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if (!programMemory->getIntValue(expr->varId(), result))
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*error = true;
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}
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else if (expr->isComparisonOp()) {
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MathLib::bigint result1(0), result2(0);
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execute(expr->astOperand1(), programMemory, &result1, error);
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execute(expr->astOperand2(), programMemory, &result2, error);
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if (expr->str() == "<")
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*result = result1 < result2;
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else if (expr->str() == "<=")
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*result = result1 <= result2;
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else if (expr->str() == ">")
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*result = result1 > result2;
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else if (expr->str() == ">=")
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*result = result1 >= result2;
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else if (expr->str() == "==")
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*result = result1 == result2;
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else if (expr->str() == "!=")
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*result = result1 != result2;
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}
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else if (expr->isAssignmentOp()) {
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execute(expr->astOperand2(), programMemory, result, error);
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if (!expr->astOperand1() || !expr->astOperand1()->varId())
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*error = true;
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if (*error)
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return;
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if (expr->str() == "=") {
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programMemory->setIntValue(expr->astOperand1()->varId(), *result);
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return;
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}
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long long intValue;
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if (!programMemory->getIntValue(expr->astOperand1()->varId(), &intValue)) {
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*error = true;
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return;
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}
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if (expr->str() == "+=")
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programMemory->setIntValue(expr->astOperand1()->varId(), intValue + *result);
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else if (expr->str() == "-=")
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programMemory->setIntValue(expr->astOperand1()->varId(), intValue - *result);
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else if (expr->str() == "*=")
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programMemory->setIntValue(expr->astOperand1()->varId(), intValue * *result);
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else if (expr->str() == "/=" && *result != 0)
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programMemory->setIntValue(expr->astOperand1()->varId(), intValue / *result);
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else if (expr->str() == "%=" && *result != 0)
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programMemory->setIntValue(expr->astOperand1()->varId(), intValue % *result);
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else if (expr->str() == "&=")
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programMemory->setIntValue(expr->astOperand1()->varId(), intValue & *result);
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else if (expr->str() == "|=")
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programMemory->setIntValue(expr->astOperand1()->varId(), intValue | *result);
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else if (expr->str() == "^=")
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programMemory->setIntValue(expr->astOperand1()->varId(), intValue ^ *result);
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}
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else if (Token::Match(expr, "++|--")) {
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if (!expr->astOperand1() || expr->astOperand1()->varId() == 0U)
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*error = true;
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else {
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long long intValue;
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if (!programMemory->getIntValue(expr->astOperand1()->varId(), &intValue))
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*error = true;
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else {
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if (intValue == 0 &&
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expr->str() == "--" &&
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expr->astOperand1()->variable() &&
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expr->astOperand1()->variable()->isUnsigned())
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*error = true; // overflow
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*result = intValue + (expr->str() == "++" ? 1 : -1);
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programMemory->setIntValue(expr->astOperand1()->varId(), *result);
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}
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}
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}
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else if (expr->isArithmeticalOp() && expr->astOperand1() && expr->astOperand2()) {
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MathLib::bigint result1(0), result2(0);
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execute(expr->astOperand1(), programMemory, &result1, error);
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execute(expr->astOperand2(), programMemory, &result2, error);
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if (expr->str() == "+")
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*result = result1 + result2;
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else if (expr->str() == "-")
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*result = result1 - result2;
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else if (expr->str() == "*") {
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if (result2 && (result1 > std::numeric_limits<MathLib::bigint>::max()/result2))
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*error = true;
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else
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*result = result1 * result2;
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} else if (result2 == 0)
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*error = true;
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else if (expr->str() == "/")
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*result = result1 / result2;
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else if (expr->str() == "%")
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*result = result1 % result2;
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else if (expr->str() == "<<") {
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if (result2 < 0 || result1 < 0 || result2 >= MathLib::bigint_bits) { // don't perform UB
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*error= true;
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} else {
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*result = result1 << result2;
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}
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} else if (expr->str() == ">>") {
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if (result2 < 0) { // don't perform UB
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*error=true;
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} else {
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*result = result1 >> result2;
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}
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}
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}
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else if (expr->str() == "&&") {
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bool error1 = false;
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execute(expr->astOperand1(), programMemory, result, &error1);
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if (!error1 && *result == 0)
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*result = 0;
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else {
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bool error2 = false;
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execute(expr->astOperand2(), programMemory, result, &error2);
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if (error1 && error2)
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*error = true;
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if (error2)
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*result = 1;
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else
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*result = !!*result;
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}
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}
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else if (expr->str() == "||") {
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execute(expr->astOperand1(), programMemory, result, error);
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if (*result == 0 && *error == false)
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execute(expr->astOperand2(), programMemory, result, error);
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}
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else if (expr->str() == "!") {
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execute(expr->astOperand1(), programMemory, result, error);
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*result = !(*result);
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}
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else if (expr->str() == "," && expr->astOperand1() && expr->astOperand2()) {
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execute(expr->astOperand1(), programMemory, result, error);
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execute(expr->astOperand2(), programMemory, result, error);
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}
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else if (expr->str() == "[" && expr->astOperand1() && expr->astOperand2()) {
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const Token *tokvalue = nullptr;
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if (!programMemory->getTokValue(expr->astOperand1()->varId(), &tokvalue)) {
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auto tokvalue_it = std::find_if(expr->astOperand1()->values().begin(),
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expr->astOperand1()->values().end(),
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std::mem_fn(&ValueFlow::Value::isTokValue));
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if (tokvalue_it == expr->astOperand1()->values().end()) {
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*error = true;
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return;
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}
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tokvalue = tokvalue_it->tokvalue;
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}
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if (!tokvalue || !tokvalue->isLiteral()) {
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*error = true;
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return;
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}
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const std::string strValue = tokvalue->strValue();
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MathLib::bigint index = 0;
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execute(expr->astOperand2(), programMemory, &index, error);
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if (index >= 0 && index < strValue.size())
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*result = strValue[index];
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else if (index == strValue.size())
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*result = 0;
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else
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*error = true;
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}
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else
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*error = true;
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}
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