bool Plan::fromFile(const char* fileName) {
std::ifstream file(fileName);
if (!file.is_open())
return false;
std::string token;
file >> token;
root = std::move(buildOperator(token));
parse(*root, file);
return true;
}
//iterate through stringstream from its end and parse operands(simple predicates) and operators(composite logical operations)
Predicate* PredicateBuilder::build(string predicateLine) {
predicate_stack = new stack<Predicate*>();
stringstream saver("");
bool operand = true;
try {
for (int i = predicateLine.length() - 1; i >= 0; i--) {
if (predicateLine[i] == ')') continue;
if (predicateLine[i] == ',' || predicateLine[i] == '(') {
string op = saver.str(); /*rotiranje stringa*/
strRotate(op);
if (operand) buildOperand(op);
else buildOperator(op);
saver.str(""); /*resetujem stream*/
if (predicateLine[i] == '(') operand = false;
else operand = true;
continue;
}
if (predicateLine[i] == ' ' && !operand) {
continue;
}
saver << predicateLine[i];
}
string op = saver.str();
strRotate(op);
if (!operand) buildOperator(op);
else buildOperand(op);
root = predicate_stack->top();
predicate_stack->pop();
}
catch (EXCEPTION* e) {
root = nullptr;
}
delete predicate_stack; // delete memory allocated for stack
return root; // return pointer to first operator in composite predicate
}
static void parse(PlanOperator& op, std::ifstream& i) {
switch (op.getOperatorType()) {
case OperatorType::TableScan: {
TableScan& t = static_cast<TableScan&>(op);
i >> t.name;
break;
}
case OperatorType::MergeJoin: {
MergeJoin& m = static_cast<MergeJoin&>(op);
readIntList(m.attributeIdsLeft, i);
m.cmp = readComparator(i);
readIntList(m.attributeIdsRight, i);
std::string opCode;
i >> opCode;
std::unique_ptr<PlanOperator> l(std::move(buildOperator(opCode)));
parse(*l, i);
m.setLeft(l);
i >> opCode;
std::unique_ptr<PlanOperator> r(std::move(buildOperator(opCode)));
parse(*r, i);
m.setRight(r);
break;
}
case OperatorType::Select: {
Select& s = static_cast<Select&>(op);
readIntList(s.attributeIds, i);
s.cmp = readComparator(i);
std::string constant;
for (unsigned j=0, limit=s.attributeIds.size(); j<limit; ++j) {
i >> constant;
s.constants.push_back(constant);
}
std::string opCode;
i >> opCode;
std::unique_ptr<PlanOperator> c(std::move(buildOperator(opCode)));
parse(*c, i);
s.setChild(c);
break;
}
case OperatorType::Project: {
Project& p = static_cast<Project&>(op);
readIntList(p.attributeIds, i);
std::string opCode;
i >> opCode;
std::unique_ptr<PlanOperator> c(std::move(buildOperator(opCode)));
parse(*c, i);
p.setChild(c);
break;
}
case OperatorType::Sort: {
Sort& s = static_cast<Sort&>(op);
readIntList(s.attributeIds, i);
s.order = readSortOrder(i);
std::string opCode;
i >> opCode;
std::unique_ptr<PlanOperator> c(std::move(buildOperator(opCode)));
parse(*c, i);
s.setChild(c);
break;
}
default: throw;
}
}
