static IEnumerable <DataCenterAddress> ReadAddresses(DataCenterSimpleRegion region)
{
var reader = region.GetReader(0);
for (var i = 0; i < region.Count; i++)
{
yield return(ReadAddress(reader));
}
}
public DataCenterStringTable(DataCenterSegmentedRegion data,
DataCenterSegmentedSimpleRegion table, DataCenterSimpleRegion addresses,
bool names, DataCenterStringOptions options)
{
var count = (int)addresses.Count;
_intern = options.HasFlag(DataCenterStringOptions.Intern);
_strings = new ConcurrentDictionary <DataCenterAddress, string>(
Environment.ProcessorCount, count);
var lazy = options.HasFlag(DataCenterStringOptions.Lazy);
// We only need the address list if we are eagerly loading strings
// and thus verifying the integrity of the regions, or if we are
// loading the names table which is always accessed by index. The
// values table is never accessed by index.
if (names || !lazy)
{
var addrs = new List <DataCenterAddress>(count);
for (uint i = 0; i < addresses.Count; i++)
{
var addr = DataCenter.ReadAddress(addresses.GetReader(i));
if (addr == DataCenterAddress.Invalid)
{
throw new InvalidDataException($"String address {addr} is invalid.");
}
addrs.Add(addr);
}
_addresses = addrs;
}
if (!lazy)
{
foreach (var(i, segment) in table.Segments.WithIndex())
{
long last = -1;
for (uint j = 0; j < segment.Count; j++)
{
var reader = segment.GetReader(j);
// This hash only has a tiny amount of collisions in a
// typical data center.
var hash = reader.ReadUInt32();
if (hash < last)
{
throw new InvalidDataException(
$"String hash {hash} is less than previous hash {last}.");
}
last = hash;
var bucket = (hash ^ hash >> 16) % table.Segments.Count;
if (bucket != i)
{
throw new InvalidDataException(
$"String bucket index {i} does not match expected index {bucket}.");
}
// This includes the NUL character.
var length = reader.ReadUInt32() - 1;
var index = reader.ReadUInt32() - 1;
if (index >= _addresses.Count)
{
throw new InvalidDataException(
$"String index {index} is greater than {_addresses.Count}.");
}
var address1 = DataCenter.ReadAddress(reader);
var address2 = _addresses[(int)index];
if (address1 != address2)
{
throw new InvalidDataException(
$"String address {address1} does not match expected address {address2}.");
}
var value = data.GetReader(address1).ReadString();
if (value.Length != length)
{
throw new InvalidDataException(
$"String length {value.Length} does not match recorded length {length}.");
}
if (!_strings.TryAdd(address1, _intern ? string.Intern(value) : value))
{
throw new InvalidDataException(
$"String address {address1} already added to the table.");
}
}
}
}
else
{
_data = data;
}
}