/** @brief determines if entry can satisfy interest
* @param hash SHA256 hash of PublisherPublicKeyLocator if exists in interest, otherwise ignored
*/
static bool
matchesSimpleSelectors(const Interest& interest, ndn::ConstBufferPtr& hash,
const Index::Entry& entry)
{
const Name& fullName = entry.getName();
if (!interest.getName().isPrefixOf(fullName))
return false;
size_t nSuffixComponents = fullName.size() - interest.getName().size();
if (interest.getMinSuffixComponents() >= 0 &&
nSuffixComponents < static_cast<size_t>(interest.getMinSuffixComponents()))
return false;
if (interest.getMaxSuffixComponents() >= 0 &&
nSuffixComponents > static_cast<size_t>(interest.getMaxSuffixComponents()))
return false;
if (!interest.getExclude().empty() &&
entry.getName().size() > interest.getName().size() &&
interest.getExclude().isExcluded(entry.getName()[interest.getName().size()])) {
return false;
}
if (!interest.getPublisherPublicKeyLocator().empty())
{
if (*entry.getKeyLocatorHash() != *hash)
return false;
}
return true;
}
std::pair<int64_t,Name>
Index::selectChild(const Interest& interest,
IndexContainer::const_iterator startingPoint) const
{
BOOST_ASSERT(startingPoint != m_indexContainer.end());
bool isLeftmost = (interest.getChildSelector() <= 0);
ndn::ConstBufferPtr hash;
if (!interest.getPublisherPublicKeyLocator().empty())
{
KeyLocator keyLocator = interest.getPublisherPublicKeyLocator();
const Block& block = keyLocator.wireEncode();
hash = ndn::crypto::sha256(block.wire(), block.size());
}
if (isLeftmost)
{
for (IndexContainer::const_iterator it = startingPoint;
it != m_indexContainer.end(); ++it)
{
if (!interest.getName().isPrefixOf(it->getName()))
return std::make_pair(0, Name());
if (matchesSimpleSelectors(interest, hash, (*it)))
return std::make_pair(it->getId(), it->getName());
}
}
else
{
IndexContainer::const_iterator boundary = m_indexContainer.lower_bound(interest.getName());
if (boundary == m_indexContainer.end() || !interest.getName().isPrefixOf(boundary->getName()))
return std::make_pair(0, Name());
Name successor = interest.getName().getSuccessor();
IndexContainer::const_iterator last = interest.getName().size() == 0 ?
m_indexContainer.end() : m_indexContainer.lower_bound(interest.getName().getSuccessor());
while (true)
{
IndexContainer::const_iterator prev = last;
if (prev != boundary) {
--prev;
}
if (prev == boundary)
{
bool isMatch = matchesSimpleSelectors(interest, hash, (*prev));
if (isMatch)
{
return std::make_pair(prev->getId(), prev->getName());
}
else
return std::make_pair(0, Name());
}
IndexContainer::const_iterator first =
m_indexContainer.lower_bound(prev->getName().getPrefix(interest.getName().size() + 1));
IndexContainer::const_iterator match =
std::find_if(first, last, bind(&matchesSimpleSelectors, interest, hash, _1));
if (match != last)
{
return std::make_pair(match->getId(), match->getName());
}
last = first;
}
}
return std::make_pair(0, Name());
}
