void hashtable_database_writer::store(const hash_digest& key_hash,
size_t value_size, write_value_function write)
{
// Calculate the end of the last record.
const uint64_t header_size = 24 + buckets_ * 8;
const uint64_t records_end_offset = header_size + total_records_size_;
// [ tx hash ] 32
// [ varuint value size ]
// [ ... value data ... ]
// [ next tx in bucket ] 8
const size_t record_size =
32 + variable_uint_size(value_size) + value_size + 8;
// If a record crosses a page boundary then we align it with
// the beginning of the next page.
const size_t record_begin =
align_if_crossing_page(page_size_, records_end_offset, record_size);
BITCOIN_ASSERT(file_.size() >= record_begin + record_size);
// We will insert new transactions at the beginning of the bucket's list.
// I assume that more recent transactions in the blockchain are used
// more often than older ones.
// We lookup the existing value in the bucket first.
const uint64_t bucket_index = remainder(key_hash.data(), buckets_);
BITCOIN_ASSERT(bucket_index < buckets_);
const uint64_t previous_bucket_value = read_bucket_value(bucket_index);
// Now begin writing the record itself.
uint8_t* entry = file_.data() + record_begin;
auto serial = make_serializer(entry);
serial.write_hash(key_hash);
serial.write_variable_uint(value_size);
// Call the supplied callback to serialize the data.
write(serial.iterator());
serial.set_iterator(serial.iterator() + value_size);
serial.write_8_bytes(previous_bucket_value);
BITCOIN_ASSERT(serial.iterator() == entry + record_size);
// Change file size value at file start.
// This must be done first so any subsequent writes don't
// overwrite this record in case of a crash or interruption.
BITCOIN_ASSERT(record_begin >= header_size);
const uint64_t alignment_padding =
record_begin - header_size - total_records_size_;
BITCOIN_ASSERT(alignment_padding <= page_size_);
total_records_size_ += record_size + alignment_padding;
// Now add record to bucket.
const uint64_t record_begin_offset = record_begin - header_size;
link_record(bucket_index, record_begin_offset);
}
aldl_record_t *process_data(aldl_conf_t *aldl) {
aldl_record_t *rec = aldl_create_record(aldl);
aldl_fill_record(aldl,rec);
link_record(rec,aldl);
return rec;
}
