void
process_unset(vector<string> cmd_str) {
int val;
int prev_tid, prev_val_tid;
int prev_var_val_cnt, prev_var_val;
Transaction* t = trans_stack.back();
t->clear_value(cmd_str[1]);
// if the variable was modified last in another transaction, add this transaction to the
// var_tid_stack
if ( (!var_tid_stack[cmd_str[1]].empty()) && (t->get_tid() != var_tid_stack[cmd_str[1]].back())) {
prev_tid = var_tid_stack[cmd_str[1]].back();
prev_var_val = trans_stack[prev_tid]->get_value(cmd_str[1]);
if (!val_tid_stack[prev_var_val].empty()) {
prev_val_tid = val_tid_stack[prev_var_val].back();
}
prev_var_val_cnt = trans_stack[prev_val_tid]->get_valMap_value(prev_var_val);
var_tid_stack[cmd_str[1]].push_back(t->get_tid());
// we need a new label -9999 to indicate that the variable was unset
// for process_get aka displaying purposes; use it to update current transaction
t->add_value(cmd_str[1], -9999);
//if value of var is 0, then look for previous tid count and add that to the present tid
if (prev_var_val != -1) {
//the prev var value has changed so add current tid to the val_tid_stack
val_tid_stack[prev_var_val].push_back(t->get_tid());
t->set_valMap_value(prev_var_val, --prev_var_val_cnt);
}
}
}
