public override int Read(IOfcNumberWriter writer, Block block, StreamBitReader reader)
{
// ReSharper disable once AssignmentInConditionalExpression
if (block.OverrideGlobalNb = reader.ReadByte(1) > 0)
{
block.NeededBits = reader.ReadByte(Metadata.MaxNeededBitsNeededBitsNumber);
}
// ReSharper disable once AssignmentInConditionalExpression
if (!Metadata.IsAbsolute)
{
if (block.AbsoluteSign = reader.ReadByte(1) > 0)
{
block.IsSignNegative = reader.ReadByte(1) > 0;
}
}
var hasAbsoluteSign = block.AbsoluteSign || Metadata.IsAbsolute;
var isNegative = block.AbsoluteSign && block.IsSignNegative || Metadata.IsAbsolute && Metadata.IsNegative;
for (var i = 0; i < block.Length; i++)
{
var num = new OfcNumber();
if (!hasAbsoluteSign)
{
isNegative = reader.ReadByte(1) > 0;
}
num.Number = ((long)reader.Read(Metadata.MaxNeededBitsNumber)) * (isNegative ? -1 : 1);
writer.Write(num);
}
return(block.Length);
}
/// <summary>
/// Reads a Single Value from its binary representation without the control bit (isBlock)
/// </summary>
/// <param name="reader"></param>
/// <param name="metadata"></param>
/// <returns></returns>
public static OfcNumber ReadSingleValueWithoutControlBit(StreamBitReader reader, BlockyMetadata metadata)
{
var value = new OfcNumber();
if (!metadata.IsAbsolute)
{
value.IsNegative = reader.ReadByte(1) > 0;
}
else
{
value.IsNegative = metadata.IsNegative;
}
value.Number = (long)reader.Read(metadata.MaxNeededBitsNumber);
var isExpNegative = reader.ReadByte(1) > 0;
value.Exponent = (short)reader.Read(metadata.MaxNeededBitsExponent); // Bug: Potentually reading exp even though NoExp is set. Same in writing method! (Ineffizient)
if (isExpNegative)
{
value.Exponent *= -1;
}
return(value);
}
/// <summary>
/// Reads the metadata in its binary form
/// </summary>
/// <param name="reader"></param>
/// <returns></returns>
public static BlockyMetadata FromBitStream(StreamBitReader reader)
{
var metadata = new BlockyMetadata {
ValueCount = (int)reader.Read(31)
};
// ReSharper disable once AssignmentInConditionalExpression
if (metadata.IsAbsolute = reader.ReadByte(1) > 0)
{
metadata.IsNegative = reader.ReadByte(1) > 0;
}
metadata.MaxNeededBitsExponent = reader.ReadByte(4);
metadata.MaxNeededBitsNumber = reader.ReadByte(6);
metadata.MaxNeededBitsNeededBitsNumber = Utility.GetNeededBits(metadata.MaxNeededBitsNumber);
metadata.LargestPossibleValue = Utility.GetMaxValue(metadata.MaxNeededBitsNumber);
return(metadata);
}
/// <summary>
/// Exclusive IsBlock
/// </summary>
/// <param name="reader"></param>
/// <param name="metadata"></param>
/// <returns></returns>
public static Block ReadDefaultBlockHeader(StreamBitReader reader, BlockyMetadata metadata)
{
var block = new Block();
// ReSharper disable once AssignmentInConditionalExpression
if (block.HasExponent = reader.ReadByte(1) > 0)
{
var negative = reader.ReadByte(1) > 0;
block.Exponent = (short)reader.Read(metadata.MaxNeededBitsExponent);
if (negative)
{
block.Exponent *= -1;
}
}
// ReSharper disable once AssignmentInConditionalExpression
if (block.HasPattern = reader.ReadByte(1) > 0)
{
block.Pattern = (Block.PatternType)reader.ReadByte(2);
}
block.Length = reader.ReadByte(8);
return(block);
}
public bool DecompressNext()
{
var blockLength = (int)_streamBitReader.Read(32);
if (blockLength == 0)
{
return(false); // The compression will write 0 as int32 at the end - a block with 0 length = the end
}
var numbers = new char[blockLength][];
var numberLengths = new int[blockLength];
var expLengths = new int[blockLength];
var averageNumberLength = _streamBitReader.ReadByte(8);
var averageExpLength = _streamBitReader.ReadByte(8);
#region Reconstructing value lengths from bit mask and initializing numbers array
for (var i = 0; i < blockLength; i++)
{
var isSmallerThanAvg = _streamBitReader.ReadByte(1) * -2 + 1; // * -2 + 1 transforms a 0 - 1 isNegative bool into a -1 or 1 multiplier ;)
var diff = 0;
while (_streamBitReader.ReadByte(1) == 0)
{
diff++;
}
numberLengths[i] = averageNumberLength + diff * isSmallerThanAvg;
}
for (var i = 0; i < blockLength; i++)
{
var isSmallerThanAvg = _streamBitReader.ReadByte(1) * -2 + 1; // * -2 + 1 transforms a 0 - 1 isNegative bool into a -1 or 1 multiplier ;)
var diff = 0;
while (_streamBitReader.ReadByte(1) == 0)
{
diff++;
}
expLengths[i] = averageExpLength + diff * isSmallerThanAvg;
var thisNumLength = numberLengths[i];
if (expLengths[i] > 0)
{
thisNumLength += expLengths[i] + 1;
}
numbers[i] = new char[thisNumLength];
}
#endregion
var changed = true;
for (var digitIndex = 0; changed; digitIndex++)
{
changed = false;
for (var i = 0; i < blockLength; i++)
{
if (numberLengths[i] > digitIndex)
{
changed = true;
numbers[i][digitIndex] = (char)_stream.ReadByte();
}
}
}
for (var i = 0; i < blockLength; i++)
{
if (expLengths[i] > 0)
{
numbers[i][numberLengths[i]] = 'e';
}
}
changed = true;
for (var digitIndex = 0; changed; digitIndex++)
{
changed = false;
for (var i = 0; i < blockLength; i++)
{
if (expLengths[i] > digitIndex)
{
changed = true;
numbers[i][numberLengths[i] + 1 + digitIndex] = (char)_stream.ReadByte();
}
}
}
for (var i = 0; i < numbers.Length; i++)
{
_output.Report(new string(numbers[i]));
}
return(true);
}