std::string
ustring::getstats (bool verbose)
{
ustring_read_lock_t read_lock (ustring_mutex());
std::ostringstream out;
if (verbose) {
out << "ustring statistics:\n";
out << " ustring requests: " << ustring_stats_constructed
<< ", unique " << ustring_stats_unique << "\n";
out << " ustring memory: " << Strutil::memformat(ustring_stats_memory)
<< "\n";
} else {
out << "requests: " << ustring_stats_constructed
<< ", unique " << ustring_stats_unique
<< ", " << Strutil::memformat(ustring_stats_memory);
}
#ifndef NDEBUG
// See if our hashing is pathological by checking if there are multiple
// strings that ended up with the same hash.
UstringTable &table (ustring_table());
std::map<size_t,int> hashes;
int collisions = 0;
int collision_max = 0;
size_t most_common_hash = 0;
for (UstringTable::const_iterator s = table.begin(), e = table.end();
s != e; ++s) {
// Pretend the (const char *) in the string table is a ustring (it is!)
const ustring &us = *((ustring *)(&s->first));
bool init = (hashes.find(us.hash()) == hashes.end());
int &c (hashes[us.hash()]); // Find/create the count for this hash
if (init)
c = 0;
if (++c > 1) { // Increment it, and if it's shared...
++collisions; // register a collision
if (c > collision_max) { // figure out the largest number
collision_max = c; // of shared collisions
most_common_hash = us.hash();
}
}
}
out << (verbose ? " " : ", ") << collisions << " hash collisions (max "
<< collision_max << (verbose ? ")\n" : ")");
// DEBUG renders only -- reveal the strings sharing the most common hash
if (collision_max > 2) {
out << (verbose ? "" : "\n") << " Most common hash "
<< most_common_hash << " was shared by:\n";
for (UstringTable::const_iterator s = table.begin(), e = table.end();
s != e; ++s) {
const ustring &us = *((ustring *)(&s->first));
if (us.hash() == most_common_hash)
out << " \"" << us << "\"\n";
}
}
#endif
return out.str();
}
std::string
ustring::getstats (bool verbose)
{
ustring_read_lock_t read_lock (ustring_mutex());
std::ostringstream out;
if (verbose) {
out << "ustring statistics:\n";
out << " ustring requests: " << ustring_stats_constructed
<< ", unique " << ustring_stats_unique << "\n";
out << " ustring memory: " << Strutil::memformat(ustring_stats_memory)
<< "\n";
} else {
out << "requests: " << ustring_stats_constructed
<< ", unique " << ustring_stats_unique
<< ", " << Strutil::memformat(ustring_stats_memory);
}
return out.str();
}
size_t
ustring::memory ()
{
ustring_read_lock_t read_lock (ustring_mutex());
return ustring_stats_memory;
}