public override ushort Read(int count)
{
this.CheckBuffer();
if (this.remainingBits < count)
{
int delta = count - this.remainingBits;
ushort lowBits = (ushort)(this.byteBuffer << delta);
this.byteBuffer = BigEndian.Read2(stream);
this.remainingBits = 16 - delta;
ushort highBits = (ushort)(this.byteBuffer >> this.remainingBits);
this.byteBuffer ^= (ushort)(highBits << this.remainingBits);
return((ushort)(lowBits | highBits));
}
this.remainingBits -= count;
ushort bits = (ushort)(this.byteBuffer >> this.remainingBits);
this.byteBuffer ^= (ushort)(bits << this.remainingBits);
return(bits);
}
public override bool Push(bool bit)
{
bool flushed = false;
if (this.waitingBits >= 16)
{
BigEndian.Write2(this.stream, this.byteBuffer);
this.waitingBits = 0;
this.byteBuffer = 0;
flushed = true;
}
if (bit)
{
this.byteBuffer |= (ushort)(0x8000 >> this.waitingBits);
}
++this.waitingBits;
return(flushed);
}
internal static void EncodeModuled(Stream source, Stream destination)
{
int size = (int)(source.Length - source.Position);
byte[] buffer = new byte[size];
source.Read(buffer, 0, size);
int pos = 0;
if (size > 0xffff)
{
throw new CompressionException(Properties.Resources.KosinskiPlusTotalSizeTooLarge);
}
int remainingSize = size;
int compBytes = 0;
if (remainingSize > 0x1000)
{
remainingSize = 0x1000;
}
BigEndian.Write2(destination, (ushort)size);
for (; ;)
{
EncodeInternal(destination, buffer, pos, remainingSize);
compBytes += remainingSize;
pos += remainingSize;
if (compBytes >= size)
{
break;
}
remainingSize = Math.Min(0x1000, size - compBytes);
}
}
internal static void Decode(Stream source, Stream destination, Endianness headerEndianness)
{
long decompressedBytes = 0;
long fullSize;
if (headerEndianness == Endianness.BigEndian)
{
fullSize = BigEndian.Read2(source);
}
else
{
fullSize = LittleEndian.Read2(source);
}
for (;;)
{
DecodeInternal(source, destination, ref decompressedBytes);
if (decompressedBytes >= fullSize)
{
break;
}
// Skip the padding between modules
int b;
long paddingEnd = (((source.Position - 2) + 0xF) & ~0xF) + 2;
while (source.Position < paddingEnd)
{
b = source.ReadByte();
if (b == -1)
{
throw new EndOfStreamException();
}
}
}
}
private static void EncodeInternal(Stream destination, byte[] buffer, long pos, long slidingWindow, long recLength, long size)
{
UInt16LEOutputBitStream bitStream = new UInt16LEOutputBitStream(destination);
MemoryStream data = new MemoryStream();
if (size > 0)
{
long bPointer = 1, iOffset = 0;
bitStream.Push(true);
NeutralEndian.Write1(data, buffer[pos]);
while (bPointer < size)
{
long iCount = Math.Min(recLength, size - bPointer);
long iMax = Math.Max(bPointer - slidingWindow, 0);
long k = 1;
long i = bPointer - 1;
do
{
long j = 0;
while (buffer[pos + i + j] == buffer[pos + bPointer + j])
{
if (++j >= iCount)
{
break;
}
}
if (j > k)
{
k = j;
iOffset = i;
}
} while (i-- > iMax);
iCount = k;
if (iCount == 1)
{
Push(bitStream, true, destination, data);
NeutralEndian.Write1(data, buffer[pos + bPointer]);
}
else if (iCount == 2 && bPointer - iOffset > 256)
{
Push(bitStream, true, destination, data);
NeutralEndian.Write1(data, buffer[pos + bPointer]);
--iCount;
}
else if (iCount < 6 && bPointer - iOffset <= 256)
{
Push(bitStream, false, destination, data);
Push(bitStream, false, destination, data);
Push(bitStream, (((iCount - 2) >> 1) & 1) != 0, destination, data);
Push(bitStream, ((iCount - 2) & 1) != 0, destination, data);
NeutralEndian.Write1(data, (byte)(~(bPointer - iOffset - 1)));
}
else
{
Push(bitStream, false, destination, data);
Push(bitStream, true, destination, data);
long off = bPointer - iOffset - 1;
ushort info = (ushort)(~((off << 8) | (off >> 5)) & 0xFFF8);
if (iCount < 10) // iCount - 2 < 8
{
info |= (ushort)(iCount - 2);
BigEndian.Write2(data, info);
}
else
{
BigEndian.Write2(data, info);
NeutralEndian.Write1(data, (byte)(iCount - 1));
}
}
bPointer += iCount;
}
}
Push(bitStream, false, destination, data);
Push(bitStream, true, destination, data);
// If the bit stream was just flushed, write an empty bit stream that will be read just before the end-of-data
// sequence below.
if (!bitStream.HasWaitingBits)
{
NeutralEndian.Write1(data, 0);
NeutralEndian.Write1(data, 0);
}
NeutralEndian.Write1(data, 0);
NeutralEndian.Write1(data, 0xF0);
NeutralEndian.Write1(data, 0);
bitStream.Flush(true);
byte[] bytes = data.ToArray();
destination.Write(bytes, 0, bytes.Length);
}
private static void Decode(Stream input, Stream output, Endianness endianness)
{
using (PaddedStream paddedInput = new PaddedStream(input, 2, PaddedStreamMode.Read))
{
byte packetLength = NeutralEndian.Read1(paddedInput);
var readBitfield = GetBitfieldReader(NeutralEndian.Read1(paddedInput));
ushort incrementingValue;
ushort commonValue;
InputBitStream <ushort> bitStream;
Action <Stream, ushort> write2;
if (endianness == Endianness.BigEndian)
{
incrementingValue = BigEndian.Read2(paddedInput);
commonValue = BigEndian.Read2(paddedInput);
bitStream = new UInt16BE_E_L_InputBitStream(paddedInput);
write2 = Write2BE;
}
else
{
incrementingValue = LittleEndian.Read2(paddedInput);
commonValue = LittleEndian.Read2(paddedInput);
bitStream = new UInt16LE_E_L_InputBitStream(paddedInput);
write2 = Write2LE;
}
// Loop until the end-of-data marker is found (if it is not found before the end of the stream, UInt8InputBitStream
// will throw an exception)
for (; ;)
{
if (bitStream.Get())
{
int mode = bitStream.Read(2);
int count = bitStream.Read(4);
switch (mode)
{
case 0:
case 1:
{
ushort flags = readBitfield(bitStream);
ushort outv = (ushort)(bitStream.Read(packetLength) | flags);
do
{
write2(output, outv);
outv += (ushort)mode;
} while (--count >= 0);
}
break;
case 2:
mode = -1;
goto case 0;
case 3:
{
// End of compressed data
if (count == 0xf)
{
return;
}
do
{
ushort flags = readBitfield(bitStream);
ushort outv = bitStream.Read(packetLength);
write2(output, (ushort)(outv | flags));
} while (--count >= 0);
}
break;
}
}
else
{
bool mode = bitStream.Get();
int count = bitStream.Read(4);
if (mode)
{
do
{
write2(output, commonValue);
} while (--count >= 0);
}
else
{
do
{
write2(output, incrementingValue++);
} while (--count >= 0);
}
}
}
}
}
private static void EncodeInternal(Stream input, Stream output, bool xor, long inputLength)
{
var rleSource = new List <NibbleRun>();
var counts = new SortedList <NibbleRun, long>();
using (IEnumerator <byte> unpacked = Unpacked(input))
{
// Build RLE nibble runs, RLE-encoding the nibble runs as we go along.
// Maximum run length is 8, meaning 7 repetitions.
if (unpacked.MoveNext())
{
NibbleRun current = new NibbleRun(unpacked.Current, 0);
while (unpacked.MoveNext())
{
NibbleRun next = new NibbleRun(unpacked.Current, 0);
if (next.Nibble != current.Nibble || current.Count >= 7)
{
rleSource.Add(current);
long count;
counts.TryGetValue(current, out count);
counts[current] = count + 1;
current = next;
}
else
{
++current.Count;
}
}
}
}
// We will use the Package-merge algorithm to build the optimal length-limited
// Huffman code for the current file. To do this, we must map the current
// problem onto the Coin Collector's problem.
// Build the basic coin collection.
var qt = new List <EncodingCodeTreeNode>();
foreach (var kvp in counts)
{
// No point in including anything with weight less than 2, as they
// would actually increase compressed file size if used.
if (kvp.Value > 1)
{
qt.Add(new EncodingCodeTreeNode(kvp.Key, kvp.Value));
}
}
qt.Sort();
// The base coin collection for the length-limited Huffman coding has
// one coin list per character in length of the limmitation. Each coin list
// has a constant "face value", and each coin in a list has its own
// "numismatic value". The "face value" is unimportant in the way the code
// is structured below; the "numismatic value" of each coin is the number
// of times the underlying nibble run appears in the source file.
// This will hold the Huffman code map.
// NOTE: while the codes that will be written in the header will not be
// longer than 8 bits, it is possible that a supplementary code map will
// add "fake" codes that are longer than 8 bits.
var codeMap = new SortedList <NibbleRun, KeyValuePair <long, byte> >();
// Size estimate. This is used to build the optimal compressed file.
long sizeEstimate = long.MaxValue;
// We will solve the Coin Collector's problem several times, each time
// ignoring more of the least frequent nibble runs. This allows us to find
// *the* lowest file size.
while (qt.Count > 1)
{
// Make a copy of the basic coin collection.
var q0 = new List <EncodingCodeTreeNode>(qt);
// Ignore the lowest weighted item. Will only affect the next iteration
// of the loop. If it can be proven that there is a single global
// minimum (and no local minima for file size), then this could be
// simplified to a binary search.
qt.RemoveAt(qt.Count - 1);
// We now solve the Coin collector's problem using the Package-merge
// algorithm. The solution goes here.
var solution = new List <EncodingCodeTreeNode>();
// This holds the packages from the last iteration.
var q = new List <EncodingCodeTreeNode>(q0);
int target = (q0.Count - 1) << 8, idx = 0;
while (target != 0)
{
// Gets lowest bit set in its proper place:
int val = (target & -target), r = 1 << idx;
// Is the current denomination equal to the least denomination?
if (r == val)
{
// If yes, take the least valuable node and put it into the solution.
solution.Add(q[q.Count - 1]);
q.RemoveAt(q.Count - 1);
target -= r;
}
// The coin collection has coins of values 1 to 8; copy from the
// original in those cases for the next step.
var q1 = new List <EncodingCodeTreeNode>();
if (idx < 7)
{
q1.AddRange(q0);
}
// Split the current list into pairs and insert the packages into
// the next list.
while (q.Count > 1)
{
EncodingCodeTreeNode child1 = q[q.Count - 1];
q.RemoveAt(q.Count - 1);
EncodingCodeTreeNode child0 = q[q.Count - 1];
q.RemoveAt(q.Count - 1);
q1.Add(new EncodingCodeTreeNode(child0, child1));
}
idx++;
q.Clear();
q.AddRange(q1);
q.Sort();
}
// The Coin Collector's problem has been solved. Now it is time to
// map the solution back into the length-limited Huffman coding problem.
// To do that, we iterate through the solution and count how many times
// each nibble run has been used (remember that the coin collection had
// had multiple coins associated with each nibble run) -- this number
// is the optimal bit length for the nibble run.
var baseSizeMap = new SortedList <NibbleRun, long>();
foreach (var item in solution)
{
item.Traverse(baseSizeMap);
}
// With the length-limited Huffman coding problem solved, it is now time
// to build the code table. As input, we have a map associating a nibble
// run to its optimal encoded bit length. We will build the codes using
// the canonical Huffman code.
// To do that, we must invert the size map so we can sort it by code size.
var sizeOnlyMap = new MultiSet <long>();
// This map contains lots more information, and is used to associate
// the nibble run with its optimal code. It is sorted by code size,
// then by frequency of the nibble run, then by the nibble run.
var sizeMap = new MultiSet <SizeMapItem>();
foreach (var item in baseSizeMap)
{
long size = item.Value;
sizeOnlyMap.Add(size);
sizeMap.Add(new SizeMapItem(size, counts[item.Key], item.Key));
}
// We now build the canonical Huffman code table.
// "baseCode" is the code for the first nibble run with a given bit length.
// "carry" is how many nibble runs were demoted to a higher bit length
// at an earlier step.
// "cnt" is how many nibble runs have a given bit length.
long baseCode = 0;
long carry = 0, cnt;
// This list contains the codes sorted by size.
var codes = new List <KeyValuePair <long, byte> >();
for (byte j = 1; j <= 8; j++)
{
// How many nibble runs have the desired bit length.
cnt = sizeOnlyMap.Count(j) + carry;
carry = 0;
for (int k = 0; k < cnt; k++)
{
// Sequential binary numbers for codes.
long code = baseCode + k;
long mask = (1L << j) - 1;
// We do not want any codes composed solely of 1's or which
// start with 111111, as that sequence is reserved.
if ((j <= 6 && code == mask) ||
(j > 6 && code == (mask & ~((1L << (j - 6)) - 1))))
{
// We must demote this many nibble runs to a longer code.
carry = cnt - k;
cnt = k;
break;
}
codes.Add(new KeyValuePair <long, byte>(code, j));
}
// This is the beginning bit pattern for the next bit length.
baseCode = (baseCode + cnt) << 1;
}
// With the canonical table build, the codemap can finally be built.
var tempCodemap = new SortedList <NibbleRun, KeyValuePair <long, byte> >();
using (IEnumerator <SizeMapItem> enumerator = sizeMap.GetEnumerator())
{
int pos = 0;
while (enumerator.MoveNext() && pos < codes.Count)
{
tempCodemap[enumerator.Current.NibbleRun] = codes[pos];
++pos;
}
}
// We now compute the final file size for this code table.
// 2 bytes at the start of the file, plus 1 byte at the end of the
// code table.
long tempsize_est = 3 * 8;
byte last = 0xff;
// Start with any nibble runs with their own code.
foreach (var item in tempCodemap)
{
// Each new nibble needs an extra byte.
if (item.Key.Nibble != last)
{
tempsize_est += 8;
last = item.Key.Nibble;
}
// 2 bytes per nibble run in the table.
tempsize_est += 2 * 8;
// How many bits this nibble run uses in the file.
tempsize_est += counts[item.Key] * item.Value.Value;
}
// Supplementary code map for the nibble runs that can be broken up into
// shorter nibble runs with a smaller bit length than inlining.
var supCodemap = new Dictionary <NibbleRun, KeyValuePair <long, byte> >();
// Now we will compute the size requirements for inline nibble runs.
foreach (var item in counts)
{
if (!tempCodemap.ContainsKey(item.Key))
{
// Nibble run does not have its own code. We need to find out if
// we can break it up into smaller nibble runs with total code
// size less than 13 bits or if we need to inline it (13 bits).
if (item.Key.Count == 0)
{
// If this is a nibble run with zero repeats, we can't break
// it up into smaller runs, so we inline it.
tempsize_est += (6 + 7) * item.Value;
}
else if (item.Key.Count == 1)
{
// We stand a chance of breaking the nibble run.
// This case is rather trivial, so we hard-code it.
// We can break this up only as 2 consecutive runs of a nibble
// run with count == 0.
KeyValuePair <long, byte> value;
if (!tempCodemap.TryGetValue(new NibbleRun(item.Key.Nibble, 0), out value) || value.Value > 6)
{
// The smaller nibble run either does not have its own code
// or it results in a longer bit code when doubled up than
// would result from inlining the run. In either case, we
// inline the nibble run.
tempsize_est += (6 + 7) * item.Value;
}
else
{
// The smaller nibble run has a small enough code that it is
// more efficient to use it twice than to inline our nibble
// run. So we do exactly that, by adding a (temporary) entry
// in the supplementary codemap, which will later be merged
// into the main codemap.
long code = value.Key;
byte len = value.Value;
code = (code << len) | code;
len <<= 1;
tempsize_est += len * item.Value;
supCodemap[item.Key] = new KeyValuePair <long, byte>(code, (byte)(0x80 | len));
}
}
else
{
// We stand a chance of breaking the nibble run.
byte n = item.Key.Count;
// This is a linear optimization problem subjected to 2
// constraints. If the number of repeats of the current nibble
// run is N, then we have N dimensions.
// Reference to table of linear coefficients. This table has
// N columns for each line.
byte[,] myLinearCoeffs = linearCoeffs[n - 2];
int rows = myLinearCoeffs.GetLength(0);
byte nibble = item.Key.Nibble;
// List containing the code length of each nibble run, or 13
// if the nibble run is not in the codemap.
var runlen = new List <long>();
// Initialize the list.
for (byte i = 0; i < n; i++)
{
// Is this run in the codemap?
KeyValuePair <long, byte> value;
if (tempCodemap.TryGetValue(new NibbleRun(nibble, i), out value))
{
// It is.
// Put code length in the vector.
runlen.Add(value.Value);
}
else
{
// It is not.
// Put inline length in the vector.
runlen.Add(6 + 7);
}
}
// Now go through the linear coefficient table and tally up
// the total code size, looking for the best case.
// The best size is initialized to be the inlined case.
long bestSize = 6 + 7;
int bestLine = -1;
for (int i = 0; i < rows; i++)
{
// Tally up the code length for this coefficient line.
long len = 0;
for (byte j = 0; j < n; j++)
{
byte c = myLinearCoeffs[i, j];
if (c == 0)
{
continue;
}
len += c * runlen[j];
}
// Is the length better than the best yet?
if (len < bestSize)
{
// If yes, store it as the best.
bestSize = len;
bestLine = i;
}
}
// Have we found a better code than inlining?
if (bestLine >= 0)
{
// We have; use it. To do so, we have to build the code
// and add it to the supplementary code table.
long code = 0, len = 0;
for (byte i = 0; i < n; i++)
{
byte c = myLinearCoeffs[bestLine, i];
if (c == 0)
{
continue;
}
// Is this run in the codemap?
KeyValuePair <long, byte> value;
if (tempCodemap.TryGetValue(new NibbleRun(nibble, i), out value))
{
// It is; it MUST be, as the other case is impossible
// by construction.
for (int j = 0; j < c; j++)
{
len += value.Value;
code <<= value.Value;
code |= value.Key;
}
}
}
if (len != bestSize)
{
// ERROR! DANGER! THIS IS IMPOSSIBLE!
// But just in case...
tempsize_est += (6 + 7) * item.Value;
}
else
{
// By construction, best_size is at most 12.
byte c = (byte)bestSize;
// Add it to supplementary code map.
supCodemap[item.Key] = new KeyValuePair <long, byte>(code, (byte)(0x80 | c));
tempsize_est += bestSize * item.Value;
}
}
else
{
// No, we will have to inline it.
tempsize_est += (6 + 7) * item.Value;
}
}
}
}
// Merge the supplementary code map into the temporary code map.
foreach (var item in supCodemap)
{
tempCodemap[item.Key] = item.Value;
}
// Round up to a full byte.
tempsize_est = (tempsize_est + 7) & ~7;
// Is this iteration better than the best?
if (tempsize_est < sizeEstimate)
{
// If yes, save the codemap and file size.
codeMap = tempCodemap;
sizeEstimate = tempsize_est;
}
}
// We now have a prefix-free code map associating the RLE-encoded nibble
// runs with their code. Now we write the file.
// Write header.
BigEndian.Write2(output, (ushort)((Convert.ToInt32(xor) << 15) | ((int)inputLength >> 5)));
byte lastNibble = 0xff;
foreach (var item in codeMap)
{
byte length = item.Value.Value;
// length with bit 7 set is a special device for further reducing file size, and
// should NOT be on the table.
if ((length & 0x80) != 0)
{
continue;
}
NibbleRun nibbleRun = item.Key;
if (nibbleRun.Nibble != lastNibble)
{
// 0x80 marks byte as setting a new nibble.
NeutralEndian.Write1(output, (byte)(0x80 | nibbleRun.Nibble));
lastNibble = nibbleRun.Nibble;
}
long code = item.Value.Key;
NeutralEndian.Write1(output, (byte)((nibbleRun.Count << 4) | length));
NeutralEndian.Write1(output, (byte)code);
}
// Mark end of header.
NeutralEndian.Write1(output, 0xff);
// Write the encoded bitstream.
UInt8_E_L_OutputBitStream bitStream = new UInt8_E_L_OutputBitStream(output);
// The RLE-encoded source makes for a far faster encode as we simply
// use the nibble runs as an index into the map, meaning a quick binary
// search gives us the code to use (if in the map) or tells us that we
// need to use inline RLE.
foreach (var nibbleRun in rleSource)
{
KeyValuePair <long, byte> value;
if (codeMap.TryGetValue(nibbleRun, out value))
{
long code = value.Key;
byte len = value.Value;
// len with bit 7 set is a device to bypass the code table at the
// start of the file. We need to clear the bit here before writing
// the code to the file.
len &= 0x7f;
// We can have codes in the 9-12 range due to the break up of large
// inlined runs into smaller non-inlined runs. Deal with those high
// bits first, if needed.
if (len > 8)
{
bitStream.Write((byte)((code >> 8) & 0xff), len - 8);
len = 8;
}
bitStream.Write((byte)(code & 0xff), len);
}
else
{
bitStream.Write(0x3f, 6);
bitStream.Write(nibbleRun.Count, 3);
bitStream.Write(nibbleRun.Nibble, 4);
}
}
// Fill remainder of last byte with zeroes and write if needed.
bitStream.Flush(false);
}
internal static void Encode(Stream source, Stream destination)
{
int size_bytes = (int)(source.Length - source.Position);
byte[] buffer_bytes = new byte[size_bytes + (size_bytes & 1)];
source.Read(buffer_bytes, 0, size_bytes);
int size = (size_bytes + 1) / 2;
ushort[] buffer = new ushort[size];
for (int i = 0; i < size; ++i)
{
buffer[i] = (ushort)((buffer_bytes[i * 2] << 8) | buffer_bytes[(i * 2) + 1]);
}
/*
* Here we create and populate the "LZSS graph":
*
* Each value in the uncompressed file forms a node in this graph.
* The various edges between these nodes represent LZSS matches.
*
* Using a shortest-path algorithm, these edges can be used to
* find the optimal combination of matches needed to produce the
* smallest possible file.
*
* The outputted array only contains one edge per node: the optimal
* one. This means, in order to produce the smallest file, you just
* have to traverse the graph from one edge to the next, encoding
* each match as you go along.
*/
LZSSGraphEdge[] node_meta_array = new LZSSGraphEdge[size + 1];
// Initialise the array
node_meta_array[0].cost = 0;
for (int i = 1; i < size + 1; ++i)
{
node_meta_array[i].cost = int.MaxValue;
}
// Find matches
for (int i = 0; i < size; ++i)
{
int max_read_ahead = Math.Min(0x100, size - i);
int max_read_behind = Math.Max(0, i - 0x100);
// Search for dictionary matches
for (int j = i; j-- > max_read_behind;)
{
for (int k = 0; k < max_read_ahead; ++k)
{
if (buffer[i + k] == buffer[j + k])
{
int distance = i - j;
int length = k + 1;
// Update this node's optimal edge if this one is better
if (node_meta_array[i + k + 1].cost > node_meta_array[i].cost + 1 + 16)
{
node_meta_array[i + k + 1].cost = node_meta_array[i].cost + 1 + 16;
node_meta_array[i + k + 1].previous_node_index = i;
node_meta_array[i + k + 1].match_length = k + 1;
node_meta_array[i + k + 1].match_offset = j;
}
}
else
{
break;
}
}
}
// Do literal match
// Update this node's optimal edge if this one is better (or the same, since literal matches usually decode faster)
if (node_meta_array[i + 1].cost >= node_meta_array[i].cost + 1 + 16)
{
node_meta_array[i + 1].cost = node_meta_array[i].cost + 1 + 16;
node_meta_array[i + 1].previous_node_index = i;
node_meta_array[i + 1].match_length = 0;
}
}
// Reverse the edge link order, so the array can be traversed from start to end, rather than vice versa
node_meta_array[0].previous_node_index = int.MaxValue;
node_meta_array[size].next_node_index = int.MaxValue;
for (int node_index = size; node_meta_array[node_index].previous_node_index != int.MaxValue; node_index = node_meta_array[node_index].previous_node_index)
{
node_meta_array[node_meta_array[node_index].previous_node_index].next_node_index = node_index;
}
/*
* LZSS graph complete
*/
UInt16BE_NE_H_OutputBitStream bitStream = new UInt16BE_NE_H_OutputBitStream(destination);
MemoryStream data = new MemoryStream();
for (int node_index = 0; node_meta_array[node_index].next_node_index != int.MaxValue; node_index = node_meta_array[node_index].next_node_index)
{
int next_index = node_meta_array[node_index].next_node_index;
int length = node_meta_array[next_index].match_length;
int distance = next_index - node_meta_array[next_index].match_length - node_meta_array[next_index].match_offset;
if (length != 0)
{
// Compressed
Push(bitStream, true, destination, data);
NeutralEndian.Write1(data, (byte)-distance);
NeutralEndian.Write1(data, (byte)(length - 1));
}
else
{
// Uncompressed
Push(bitStream, false, destination, data);
BigEndian.Write2(data, buffer[node_index]);
}
}
Push(bitStream, true, destination, data);
NeutralEndian.Write1(data, 0);
NeutralEndian.Write1(data, 0);
bitStream.Flush(true);
byte[] bytes = data.ToArray();
destination.Write(bytes, 0, bytes.Length);
}