C++ TableTuple::getPreviousTupleInChain方法代码示例

void AntiCacheEvictionManager::printLRUChain(PersistentTable* table, int max, bool forward)
{
    VOLT_INFO("num tuples in chain: %d", table->getNumTuplesInEvictionChain());
    VOLT_INFO("oldest tuple id: %u", table->getOldestTupleID());
    VOLT_INFO("newest tuple id: %u", table->getNewestTupleID());
    
    char chain[max * 4];
    int tuple_id;
    TableTuple tuple = table->tempTuple();
    
    if(forward)
        tuple_id = table->getOldestTupleID();
    else
        tuple_id = table->getNewestTupleID();
    
    chain[0] = '\0';
    
    int iterations = 0;
    while(iterations < table->getNumTuplesInEvictionChain() && iterations < max)
    {
        strcat(chain, itoa(tuple_id));
        strcat(chain, " ");
        
        tuple.move(table->dataPtrForTuple(tuple_id));
        
        if(forward)
            tuple_id = tuple.getNextTupleInChain();
        else
            tuple_id = tuple.getPreviousTupleInChain();
        
        iterations++;
    }
    
    VOLT_INFO("LRU CHAIN: %s", chain);
}

// for the double linked list we start from the tail of the chain and iterate backwards
bool AntiCacheEvictionManager::removeTupleDoubleLinkedList(PersistentTable* table, uint32_t removal_id) {
    
    bool tuple_found = false;
    
    int tuples_in_chain;
        
    // ids for iterating through the list
    uint32_t current_tuple_id;
    uint32_t previous_tuple_id;
    uint32_t next_tuple_id;
    uint32_t oldest_tuple_id;
    
    // assert we have tuples in the eviction chain before we try to remove anything
    tuples_in_chain = table->getNumTuplesInEvictionChain();
    
    if (tuples_in_chain <= 0)
        return false;
    
    previous_tuple_id = 0;
    oldest_tuple_id = table->getOldestTupleID();
    current_tuple_id =  table->getNewestTupleID(); // start iteration at back of chain
    
    // set the tuple to the back of the chain (i.e. the newest)
    TableTuple tuple = table->tempTuple();
    tuple.move(table->dataPtrForTuple(current_tuple_id));
        
    // we're removing the tail  of the chain, i.e. the newest tuple
    if (table->getNewestTupleID() == removal_id) {
                
        if (table->getNumTuplesInEvictionChain() == 1) { // this is the only tuple in the chain
            table->setOldestTupleID(0);
            table->setNewestTupleID(0);
        } else if(table->getNumTuplesInEvictionChain() == 2) {
            table->setNewestTupleID(oldest_tuple_id);
            table->setOldestTupleID(oldest_tuple_id);
        }
        else {
            
            tuple.move(table->dataPtrForTuple(table->getNewestTupleID()));
            
            // we need the previous tuple in the chain, since we're iterating from back to front
            previous_tuple_id = tuple.getPreviousTupleInChain();
            table->setNewestTupleID(previous_tuple_id);
        }
        tuple_found = true;
    }
    
    // we're removing the head of the chain, i.e. the oldest tuple
    if(table->getOldestTupleID() == removal_id && !tuple_found) {
                
        if (table->getNumTuplesInEvictionChain() == 1) { // this is the only tuple in the chain
            table->setOldestTupleID(0);
            table->setNewestTupleID(0);
        }
        else if(table->getNumTuplesInEvictionChain() == 2) {
            table->setNewestTupleID(table->getNewestTupleID());
            table->setOldestTupleID(table->getNewestTupleID());
        }
        else {
            
            tuple.move(table->dataPtrForTuple(table->getOldestTupleID()));
            
            next_tuple_id = tuple.getNextTupleInChain();
            table->setOldestTupleID(next_tuple_id);
        }
        tuple_found = true;
    }
    
    int iterations = 0;
    while(!tuple_found && iterations < table->getNumTuplesInEvictionChain()) {
                
        if(current_tuple_id == oldest_tuple_id)
            break;
        
        // we've found the tuple we want to remove
        if (current_tuple_id == removal_id) {
            next_tuple_id = tuple.getPreviousTupleInChain();
            
            // point previous tuple in chain to next tuple
            tuple.move(table->dataPtrForTuple(previous_tuple_id));
            tuple.setPreviousTupleInChain(next_tuple_id);
            
            // point next tuple in chain to previous tuple
            tuple.move(table->dataPtrForTuple(next_tuple_id));
            tuple.setNextTupleInChain(previous_tuple_id);
            
            tuple_found = true;
            break;
        }
        
        // advance pointers
        previous_tuple_id = current_tuple_id;
        current_tuple_id = tuple.getPreviousTupleInChain(); // iterate back to front
        tuple.move(table->dataPtrForTuple(current_tuple_id));
        
        iterations++;
    }
    
    if (tuple_found) {
//.........这里部分代码省略.........