public static Helper Deserialize(BinaryReader reader)
{
Helper helper = new Helper();
byte b = reader.ReadByte();
helper.Sign = (b & 0x80) != 0;
helper.IsReady = (b & 0x40) != 0;
helper.AlwaysUseDelta = (b & 0x20) != 0;
helper.Type = (HelperType)(b & 0x1f);
if (helper.Type == HelperType.Raw)
{
return(helper);
}
if (helper.Type == HelperType.OneStep)
{
helper.Delta = CountCompression.Deserialize(reader);
return(helper);
}
helper.DeltaBits = reader.ReadByte();
helper.Delta = (1UL << helper.DeltaBits) - 1;
return(helper);
}
public static void Decompress(BinaryReader reader, Action <int, long> values, int count)
{
if (reader.ReadByte() != VERSION)
{
throw new Exception("Invalid delta compression version.");
}
if (count == 0)
{
return;
}
int index = 0;
long value = (long)CountCompression.Deserialize(reader);
values(index, value);
if (count == 1)
{
return;
}
var helper = Helper.Deserialize(reader);
index++;
count--;
int maxIndex = index + count - 1;
if (helper.Type == HelperType.Raw)
{
while (index <= maxIndex)
{
values(index++, reader.ReadInt64());
}
return;
}
if (helper.Type == HelperType.OneStep)
{
long step = (long)helper.Delta;
if (helper.Sign == false)
{
while (index <= maxIndex)
{
values(index++, (value += step));
}
}
else
{
while (index <= maxIndex)
{
values(index++, (value -= step));
}
}
return;
}
bool readSign = helper.Type == HelperType.Delta;
ulong maxDelta = helper.Delta;
bool alwaysUseDelta = helper.AlwaysUseDelta;
bool sign = helper.Sign;
int bitCount = helper.DeltaBits;
CommonArray common = new CommonArray();
int bytesCount = (int)CountCompression.Deserialize(reader);
common.ByteArray = reader.ReadBytes(bytesCount);
ulong[] data = common.UInt64Array;
int bitIndex = 0;
for (; index <= maxIndex; index++)
{
long newValue;
bool useDelta = alwaysUseDelta || GetFlag(data, bitIndex++);
if (useDelta)
{
if (readSign)
{
sign = GetFlag(data, bitIndex);
bitIndex++;
}
long delta = (long)GetBits(data, bitIndex, bitCount);
bitIndex += bitCount;
newValue = sign ? value - delta : value + delta;
}
else
{
newValue = (long)GetValue(data, bitIndex);
bitIndex += 64;
}
values(index, newValue);
value = newValue;
}
}
