public void Process(RegularNameNode root, int totalNodes)
{
// Rules
// 1. Character index must be high enough so valueOffset is at least 1.
// That means the index is at least char value + 1
// 2. After applying above, find lowest index where the child characters
// would fit (i.e. none of the character slots desired are already
// occupied in the map)
// 3. If a node has a terminating child, any non-terminating children are
// strictly based upon the current node's valueOffet
// 4. Terminating node takes the first available index, unless it's child of
// a node that contains regular child nodes, in which case it may appear
// in the first available index, relative to the index of the first regular
// child, or at the end of the currently used slots
// 5. Each node assigns index to terminating child first, then regular children,
// and after that child nodes are processed in depth-first order
// 6. Gaps are OK
IsProcessed = false;
usedRangeMap = Enumerable.Repeat(false, totalNodes).ToList();
minFreeSlot = 0;
maxFreeSlot = 0;
// Special case: root always occupies 0
root.Index = 0;
usedRangeMap[0] = true;
++minFreeSlot;
++maxFreeSlot;
ProcessNode(root);
IsProcessed = true;
}
TerminalNameNode CreateTerminalNameNode(RegularNameNode parent, uint stringIndex)
{
var node = new TerminalNameNode();
node.Parent = parent;
node.Character = 0;
node.TailIndex = stringIndex;
nodeCache.Add(node);
parent.Children.Add(0, node);
return(node);
}
void InsertStringToTree(string s, uint index)
{
byte[] bytes = Encoding.UTF8.GetBytes(s);
RegularNameNode currNode = root;
foreach (byte b in bytes)
{
currNode = GetOrCreateRegularNameNode(currNode, b);
}
CreateTerminalNameNode(currNode, index);
}
public void Generate()
{
// Can't be bothered to reset everything, so this is a one-time only operation
if (IsGenerated)
{
throw new InvalidOperationException("Tree already generated.");
}
if (!IsFlat)
{
// 1. Sort strings
strings.Sort((x, y) => string.CompareOrdinal(x, y));
// 2. Make root
root = GetOrCreateRegularNameNode(null, 0);
// 3. Build the character tree
for (uint i = 0; i < strings.Count; ++i)
{
InsertStringToTree(strings[(int)i], i);
}
// 4. Use encoder to fill out indexes and stuff
encoder.Process(root, nodeCache.Count);
// 5. Create the output arrays
valueOffsets = new uint[encoder.TotalSlots];
tree = new uint[encoder.TotalSlots];
tails = new uint[strings.Count];
foreach (var node in nodeCache)
{
tree[node.Index] = node.ParentIndex;
var regularNode = node as RegularNameNode;
if (regularNode != null)
{
valueOffsets[regularNode.Index] = regularNode.ValueOffset;
}
else
{
var termNode = node as TerminalNameNode;
tails[termNode.TailIndex] = termNode.Index;
valueOffsets[termNode.Index] = termNode.TailIndex;
}
}
}
else
{
// Sort by length to reduce offset table size
strings.Sort((x, y) => x.Length.CompareTo(y.Length));
}
// 6. Generate lookup
for (uint i = 0; i < strings.Count; ++i)
{
stringLookup.Add(strings[(int)i], i);
}
IsGenerated = true;
}
void ProcessTerminalNode(TerminalNameNode terminalNode, RegularNameNode currNode, uint slot)
{
terminalNode.Index = slot;
terminalNode.ParentIndex = currNode.Index;
currNode.ValueOffset = terminalNode.Index;
ExtendRangeMap(terminalNode.Index);
usedRangeMap[(int)terminalNode.Index] = true;
UpdateMinFreeSlot();
// Just in case
if (terminalNode.Index + 1 > maxFreeSlot)
{
maxFreeSlot = terminalNode.Index + 1;
}
if (OutputDebug)
{
Console.Write($"[{slot}] ");
}
}
RegularNameNode GetOrCreateRegularNameNode(RegularNameNode parent, byte ch)
{
NameNode node;
if (parent != null)
{
if (!parent.Children.TryGetValue(ch, out node))
{
node = new RegularNameNode();
node.Parent = parent;
node.Character = ch;
nodeCache.Add(node);
parent.Children.Add(ch, node);
}
}
else
{
node = new RegularNameNode();
node.Character = ch;
nodeCache.Add(node);
}
return((RegularNameNode)node);
}
void ProcessNode(RegularNameNode currNode)
{
cachedRange.Clear();
if (OutputDebug)
{
writer.Write($"{currNode.Index} {(char)currNode.Character} ");
}
TerminalNameNode terminalNode = currNode.Children.Select(x => x.Value)
.FirstOrDefault(x => x is TerminalNameNode) as TerminalNameNode;
bool terminalNodeProcessed = false;
var children = currNode.Children.Select(x => x.Value).Where(x => x is RegularNameNode)
.Cast <RegularNameNode>().OrderBy(x => x.Character).ToArray();
if (children.Length > 0)
{
uint minChildIndex = Math.Max(minFreeSlot, children[0].Character + 1u);
uint minChildValue = children[0].Character;
foreach (var child in children)
{
cachedRange.Add(child.Character - minChildValue);
}
bool needExtending;
minChildIndex = FindFreeRange(minChildIndex, cachedRange, out needExtending, false);
if (terminalNode != null)
{
// Check if we can place a terminal node before our current index
int potentialTerminalIndex = (int)minChildIndex - (int)minChildValue;
if (potentialTerminalIndex < 0 || usedRangeMap[potentialTerminalIndex])
{
try
{
// Occupied, try basing children on terminating node
// This throws if it won't work
FindFreeRange(minFreeSlot + minChildValue, cachedRange, out needExtending, true);
ProcessTerminalNode(terminalNode, currNode, minFreeSlot);
minChildIndex = terminalNode.Index + minChildValue;
}
catch (Exception)
{
// Just stick it at the end
ProcessTerminalNode(terminalNode, currNode, maxFreeSlot);
minChildIndex = terminalNode.Index + minChildValue;
// Validate
FindFreeRange(minChildIndex, cachedRange, out needExtending, true);
}
}
else
{
// Put terminating node down below
ProcessTerminalNode(terminalNode, currNode, (uint)potentialTerminalIndex);
}
terminalNodeProcessed = true;
}
if (needExtending)
{
ExtendRangeMap(minChildIndex + cachedRange[cachedRange.Count - 1]);
}
for (int i = 0; i < children.Length; ++i)
{
var child = children[i];
child.Index = minChildIndex + cachedRange[i];
child.ParentIndex = currNode.Index;
usedRangeMap[(int)child.Index] = true;
}
uint lastChildIndexFree = children[children.Length - 1].Index + 1;
if (lastChildIndexFree > maxFreeSlot)
{
maxFreeSlot = lastChildIndexFree;
}
if (OutputDebug)
{
if (children.Length == 1)
{
writer.Write($"<{children[0].Index}>");
}
else
{
writer.Write($"<{children[0].Index} {children[children.Length - 1].Index}>");
}
}
if (terminalNode == null)
{
currNode.ValueOffset = children[0].Index - children[0].Character;
}
UpdateMinFreeSlot();
if (OutputDebug)
{
writer.WriteLine();
++writer.Indent;
}
foreach (var child in children)
{
ProcessNode(child);
}
if (OutputDebug)
{
--writer.Indent;
}
}
if (terminalNode != null && !terminalNodeProcessed)
{
ProcessTerminalNode(terminalNode, currNode, minFreeSlot);
if (OutputDebug)
{
writer.WriteLine();
}
}
}