const hashtable_database_reader::get_result hashtable_database_reader::get(
const hash_digest& key_hash) const
{
uint64_t bucket_index = remainder(key_hash.data(), writer_.buckets());
BITCOIN_ASSERT(bucket_index < writer_.buckets());
uint64_t record_offset = read_record_offset(file_.data(), bucket_index);
const uint64_t header_size = 24 + writer_.buckets() * 8;
const uint8_t* all_records_begin = file_.data() + header_size;
const uint8_t* all_records_end =
all_records_begin + writer_.records_size();
const uint8_t* record_begin = all_records_begin + record_offset;
// We don't know the end of a record, so we use the end of all records
// for the deserializer.
// We will be jumping around the records since it's a chained
// list per bucket.
// Begin iterating the list.
while (true)
{
auto deserial = make_deserializer(record_begin, all_records_end);
const hash_digest current_hash = deserial.read_hash();
uint64_t value_size = deserial.read_variable_uint();
if (current_hash != key_hash)
{
// Move to next record in bucket.
// Skip the transaction data.
deserial.set_iterator(deserial.iterator() + value_size);
uint64_t next_record = deserial.read_8_bytes();
if (next_record == record_doesnt_exist)
return {nullptr, nullptr};
record_begin = all_records_begin + next_record;
continue;
}
// We have the record!
return {deserial.iterator(), deserial.iterator() + value_size};
}
BITCOIN_ASSERT_MSG(false, "Broke out of unbreakable loop!");
return {nullptr, nullptr};
}
std::string read_string()
{
uint64_t string_size = read_variable_uint();
return read_fixed_string(string_size);
}