SNFMulti/GBUdb.cpp

// GBUdb.cpp
//
// (C) Copyright 2006 - 2009 ARM Research Labs, LLC
// See www.armresearch.com for the copyright terms.
//
// See GBUdb.hpp for details.

#include <iostream>
#include <fstream>
#include <cstring>
#include <unistd.h>
#include "SNFMulti/GBUdb.hpp"

using namespace std;
using namespace CodeDweller;

//// Handy utilities...
namespace SNFMulti {
//// GBUdbDataset implementations //////////////////////////////////////////////

GBUdbDataset::~GBUdbDataset() {                                                 // Shutdown a dataset.
    if(NULL != DataArray) {                                                     // If the DataArray was allocated
        delete[] DataArray;                                                     // be sure to delete it and
        DataArray = NULL;                                                       // NULL it's pointer.
    }
    MyArraySize = 0;                                                            // For safety set the size to zero
    MyFileName = "";                                                            // and "" the name.
}

GBUdbDataset::GBUdbDataset(const char* SetFileName) :                           // Open/Create a dataset.
  DataArray(NULL),                                                              // The array pointer starts as NULL.
  MyArraySize(0) {                                                              // And the size is zero.
    FileName(SetFileName);                                                      // Set the file name if provided.
    if(0 != MyFileName.length() && (0 == access(MyFileName.c_str(),F_OK))) {    // If a file name was provided and exists
        load();                                                                 // then read the file from disk.
    } else {                                                                    // If the file name was not provided
        DataArray = new GBUdbRecord[GBUdbDefaultArraySize];                     // then allocate a new Array of
        MyArraySize = GBUdbDefaultArraySize;                                    // the default size.
        DataArray[ixNextFreeNode()].RawData =                                   // The first new node is the one
          GBUdbRootNodeOffset + GBUdbRecordsPerNode;                            // right after the root node.
        DataArray[ixMatchListRoot()].RawData =                                  // Once that's up we can use it to
          newMatchNodeRoot();                                                   // allocate the first MatchNode.
    }
}

GBUdbDataset::GBUdbDataset(GBUdbDataset& Original) :                            // Copy constructor.
  DataArray(NULL),                                                              // The array pointer starts as NULL.
  MyArraySize(Original.MyArraySize),                                            // Copy the ArraySize
  MyFileName(Original.MyFileName) {                                             // Copy the name pointer.
    DataArray = new GBUdbRecord[MyArraySize];                                   // Allocate a new Array.
    memcpy(DataArray, Original.DataArray, sizeof(GBUdbRecord) * MyArraySize);   // Copy the data wholesale.
}

const char* GBUdbDataset::FileName(const char* NewName) {                       // (Re) Set the file name.
    MyFileName = "";                                                            // Delete any previous file name.
    if(NULL != NewName) {                                                       // If we've been given a non-null cstring
        MyFileName = NewName;                                                   // capture it as our file name.
    }
    return MyFileName.c_str();                                                  // Return our new FileName.
}

//// During the read, it is safe to plow through the array without
//// checking because any unknown entry points to the zero node and
//// all zero node entries point to the zero node. The read-only
//// method does not add new nodes.

GBUdbRecord& GBUdbDataset::readRecord(unsigned int IP) {                        // Read a record.
    IP = remapIP00toFF(IP);                                                     // Make the IP safe for consumption.
    int a0, a1, a2, a3;                                                         // We will break the IP into 4 octets.
    unsigned int xIP = IP;                                                      // Grab a copy of IP to maniuplate.
    const int LowOctetMask = 0x000000FF;                                        // Mask for seeing the low octet.
    const int BitsInOneOctet = 8;                                               // Number of bits to shift per octet.
    a3 = xIP & LowOctetMask; xIP >>= BitsInOneOctet;                            // Grab the a3 octet and shift the IP.
    a2 = xIP & LowOctetMask; xIP >>= BitsInOneOctet;                            // Grab the a2 octet and shift the IP.
    a1 = xIP & LowOctetMask; xIP >>= BitsInOneOctet;                            // Grab the a1 octet and shift the IP.
    a0 = xIP & LowOctetMask;                                                    // Grab the final octet.
    GBUdbIndex RecordIndex = GBUdbRootNodeOffset;                               // Starting at the root node, follow...
    RecordIndex = DataArray[RecordIndex + a0].Index();                          // Follow the node then
    if(isMatch(RecordIndex)) {                                                  // Check for a shortcut (match record).
        if(isMatch(RecordIndex, IP)) { return MatchedData(RecordIndex); }       // If we have an exact match we're done!
        else { return SafeUnknownRecord(); }                                    // If we have a mismatch we are lost...
    }
    RecordIndex = DataArray[RecordIndex + a1].Index();                          // Follow the node then
    if(isMatch(RecordIndex)) {                                                  // Check for a shortcut (match record).
        if(isMatch(RecordIndex, IP)) { return MatchedData(RecordIndex); }       // If we have an exact match we're done!
        else { return SafeUnknownRecord(); }                                    // If we have a mismatch we are lost...
    }
    RecordIndex = DataArray[RecordIndex + a2].Index();                          // Follow the node. No more match checks.
    if(isMatch(RecordIndex)) {                                                  // Check for a shortcut (match record).
        if(isMatch(RecordIndex, IP)) { return MatchedData(RecordIndex); }       // If we have an exact match we're done!
        else { return SafeUnknownRecord(); }                                    // If we have a mismatch we are lost...
    }
    return DataArray[RecordIndex + a3];                                         // Final node has our data :-)
}

//// dropRecord()
//// This code is essentially a hack of the readRecord() code. If it finds
//// the record it will return true, mark the record as GBUdbUnknown, reduce
//// the IP count, and de-allocate the Match record. Records stored in nodes
//// are set to GBUdbUnknown and the node is left in place - otherwise repeated
//// add and drop operations would lead to leaking all nodes into the match
//// record allocation space. (Node allocation is not a linked list ;-)

bool GBUdbDataset::dropRecord(unsigned int IP) {                                // Drop an IP record.
    IP = remapIP00toFF(IP);                                                     // Make the IP safe for consumption.
    int a0, a1, a2, a3;                                                         // We will break the IP into 4 octets.
    unsigned int xIP = IP;                                                      // Grab a copy of IP to maniuplate.
    const int LowOctetMask = 0x000000FF;                                        // Mask for seeing the low octet.
    const int BitsInOneOctet = 8;                                               // Number of bits to shift per octet.
    a3 = xIP & LowOctetMask; xIP >>= BitsInOneOctet;                            // Grab the a3 octet and shift the IP.
    a2 = xIP & LowOctetMask; xIP >>= BitsInOneOctet;                            // Grab the a2 octet and shift the IP.
    a1 = xIP & LowOctetMask; xIP >>= BitsInOneOctet;                            // Grab the a1 octet and shift the IP.
    a0 = xIP & LowOctetMask;                                                    // Grab the final octet.
    GBUdbIndex RecordIndex = GBUdbRootNodeOffset;                               // Starting at the root node, follow...
    GBUdbIndex Node0Index = GBUdbRootNodeOffset;                                // Keep track of our previous nodes.
    GBUdbIndex Node1Index = 0;                                                  // This node not set yet.
    GBUdbIndex Node2Index = 0;                                                  // This node not set yet.
    GBUdbIndex Node3Index = 0;                                                  // This node not set yet.

    RecordIndex = DataArray[Node0Index + a0].Index();                           // Follow the node then
    if(isMatch(RecordIndex)) {                                                  // Check for a shortcut (match record).
        if(isMatch(RecordIndex, IP)) {                                          // If we have an exact match we proceed:
            MatchedData(RecordIndex).RawData = GBUdbUnknown;                    // Set the data in the match to unknown.
            DataArray[Node0Index + a0].Index(GBUdbUnknown);                     // Remove the reference to the match record.
            deleteMatchAt(RecordIndex);                                         // Reclaim the match record for re-use.
            decreaseIPCount();                                                  // Reduce the IP count.
            return true;                                                        // Return that we were successful.
        } else { return false; }                                                // If we have a mismatch we cannot delete.
    } else {                                                                    // If this was a Node link then
        Node1Index = RecordIndex;                                               // capture the node root and get ready
    }                                                                           // to follow the next node.

    RecordIndex = DataArray[Node1Index + a1].Index();                           // Follow the node then
    if(isMatch(RecordIndex)) {                                                  // Check for a shortcut (match record).
        if(isMatch(RecordIndex, IP)) {                                          // If we have an exact match we proceed:
            MatchedData(RecordIndex).RawData = GBUdbUnknown;                    // Set the data in the match to unknown.
            DataArray[Node1Index + a1].Index(GBUdbUnknown);                     // Remove the reference to the match record.
            deleteMatchAt(RecordIndex);                                         // Reclaim the match record for re-use.
            decreaseIPCount();                                                  // Reduce the IP count.
            return true;                                                        // Return that we were successful.
        } else { return false; }                                                // If we have a mismatch we cannot delete.
    } else {                                                                    // If this was a Node link then
        Node2Index = RecordIndex;                                               // capture the node root and get ready
    }                                                                           // to follow the next node.

    RecordIndex = DataArray[Node2Index + a2].Index();                           // Follow the node then
    if(isMatch(RecordIndex)) {                                                  // Check for a shortcut (match record).
        if(isMatch(RecordIndex, IP)) {                                          // If we have an exact match we proceed:
            MatchedData(RecordIndex).RawData = GBUdbUnknown;                    // Set the data in the match to unknown.
            DataArray[Node2Index + a2].Index(GBUdbUnknown);                     // Remove the reference to the match record.
            deleteMatchAt(RecordIndex);                                         // Reclaim the match record for re-use.
            decreaseIPCount();                                                  // Reduce the IP count.
            return true;                                                        // Return that we were successful.
        } else { return false; }                                                // If we have a mismatch we cannot delete.
    } else {                                                                    // If this was a Node link then
        Node3Index = RecordIndex;                                               // capture the node root and get ready
    }                                                                           // to follow the next node.

    RecordIndex = Node3Index + a3;                                              // Follow the node.
    if(GBUdbUnknown != DataArray[RecordIndex].RawData) {                        // If there is data there then
        DataArray[RecordIndex].RawData = GBUdbUnknown;                          // mark the entry as unknown,
        decreaseIPCount();                                                      // decrease the IP count
        return true;                                                            // and return true.
    }                                                                           // If we got all the way to the end and
    return false;                                                               // didn't find a match then return false.
}

/* Ahhh, the simple life. In a single mode lightning index, each key
** octet lives in a node, so when you grow a new path you either follow
** existing nodes or make new ones. We're not doing that here, but as
** a reference here is how that is usually handled:
**
GBUdbIndex GBUdbDataset::invokeAt(GBUdbRecord& R) {                             // Invoke at Record.
    if(GBUdbUnknown == R.RawData) {                                             // If the record does not point to a
        R.Index(newNodeRoot());                                                 // node then give it a new node.
    }                                                                           // If the record already has a node
    return R.Index();                                                           // or we gave it one, then follow it.
}
*/

//// Little helper function for invokeAt()

int getOctet(int Octet, unsigned int IP) {                                      // Returns Octet number Octet from IP.
    const int BitsInOneOctet = 8;                                               // Number of bits to shift per octet.
    const int LowOctetMask = 0x000000FF;                                        // Mask for seeing the low octet.
    int BitsToShift = 0;                                                        // Assume we want a3 but
    switch(Octet) {                                                             // If we don't, use this handy switch.
        case 0: { BitsToShift = 3 * BitsInOneOctet; break; }                    // For octet 0, shift out 3 octets.
        case 1: { BitsToShift = 2 * BitsInOneOctet; break; }                    // For octet 1, shift out 2 octets.
        case 2: { BitsToShift = 1 * BitsInOneOctet; break; }                    // For octet 2, shift out 1 octets.
    }                                                                           // For octet 3, shift none more octets.
    if(0 < BitsToShift) {                                                       // If we have bits to shift then
        IP >>= BitsToShift;                                                     // shift them.
    }
    return (IP & LowOctetMask);                                                 // Exctract the octet at the bottom.
}

//// invokeAt() is a helper function that encapsulates the work of growing new
//// pathways. There are several cases to handle in a bimodal indexing scheme
//// since sometimes you extend new nodes (as commented out above), and some-
//// times you create MatchRecords, and sometimes you have collisions and
//// have to extend previous matches.... or not. All of that will become clear
//// shortly ;-) The good news is that at least invokeAt() is always supposed
//// to return the next place to go --- that is, you never get lost because if
//// the next step in the path does not exist yet then you create it.

GBUdbIndex GBUdbDataset::invokeAt(GBUdbRecord& R, unsigned int IP, int Octet, bool ExtendMatches) {

    // R is either known (goes somewhere) or unknown (we would be lost).
    // IF R is UNNKOWN then we ...
    //// create a match and return it. (No conflict, no extension, no extra node :-)
    //**** We got out of that one so we're back at the root level.

    if(GBUdbUnknown == R.RawData) {
        R.Index(newMatchRecord(IP));
        return R.Index();
    }

    // ELSE R is KNOWN then it either points to a MatchRecord or a Node.
    //// IF R points to a Node then we will simply follow it.
    //**** We got out of that one so we're back at the root level.

    if(!isMatch(R.Index())) {
        return R.Index();
    }

    // ELSE R points to a MatchRecord then we get more complex.
    //// IF the MatchRecord matches our IP then we simply follow it.
    //**** We got out of that one so we're back at the root level.

    if(isMatch(R.Index(),IP)) {
        return R.Index();
    }

    // ELSE the MatchRecord does not match then we get more complex again...
    //// IF we are Extending Matches then we...
    ////// create a new node
    ////// push the existing match onto the new node
    ////// and create a new match for the new IP on that node.
    ////// since we already have the solution we return the new match node index (skip a step).
    //**** We got out of that one so we're back at the root level.

    if(ExtendMatches) {                                                         // If we are extending matches
        GBUdbIndex I = newNodeRoot();                                           // we create a new node.
        int NewSlotForCurrentMatch =                                            // Locate the slot in that node where
          getOctet(                                                             // the current match should reside
            Octet + 1,                                                          // based on the octet after this one
            DataArray[R.Index()]                                                // by extracting that octet from
              .RawData);                                                        // the MatchReord header.
                                                                                // Then we put the current match into
        DataArray[I + NewSlotForCurrentMatch].Index(R.Index());                 // the correct slot on the new node,
        return R.Index(I);                                                      // point the current slot to that node
    }                                                                           // and return the node to be followed.

    // ELSE we are NOT Extending Matches then we...
    // ** KNOW that we are adding node a3 and dealing with the final octet **
    //// create a new node
    //// map the existing match data into the new node.
    //// delete the existing match (for reallocation). deleteMatchAt(GBUdbIndex I)
    //// map the new IP into the new node.

    GBUdbIndex I = newNodeRoot();                                               // Create a new node.
    int NewSlotForCurrentMatch =                                                // Locate the slot in that node where
      getOctet(                                                                 // the current match should reside
        Octet + 1,                                                              // based on the octet after this one
        DataArray[R.Index()]                                                    // by extracting that octet from
          .RawData);                                                            // the MatchReord header.

    if(ExtendMatches) {                                                         // If we are extending matches...
                                                                                // then we put the current match into
        DataArray[I + NewSlotForCurrentMatch].Index(R.Index());                 // the correct slot on the new node.

    } else {                                                                    // If we are not extending matches...
                                                                                // then we must be at the end node so
        DataArray[I + NewSlotForCurrentMatch].RawData =                         // we copy in the data from
          MatchedData(R.Index()).RawData;                                       // the current MatchRecord,
        deleteMatchAt(R.Index());                                               // and return the MatchRecord for re-use.
    }

    return R.Index(I);                                                          // Point the current slot to new node
}                                                                               // and return that node index to follow.

//// The "invoke" method creates all of the needed nodes starting
//// at any point where an "unwknown" entry is found.

GBUdbRecord& GBUdbDataset::invokeRecord(unsigned int IP) {                      // Invoke a record.
    if(FreeNodes() < GBUdbGrowthThreshold) grow();                              // If we need more space, make more.
    IP = remapIP00toFF(IP);                                                     // Make the IP safe for consumption.
    int a0, a1, a2, a3;                                                         // We will break the IP into 4 octets.
    unsigned int xIP = IP;                                                      // Grab a copy of IP to maniuplate.
    const int LowOctetMask = 0x000000FF;                                        // Mask for seeing the low octet.
    const bool Extend = true;                                                   // Magic number for extending Matches.
    const bool DoNotExtend = false;                                             // Magic number for NOT extending them.
    const int BitsInOneOctet = 8;                                               // Number of bits to shift per octet.
    a3 = xIP & LowOctetMask; xIP >>= BitsInOneOctet;                            // Grab the a3 octet and shift the IP.
    a2 = xIP & LowOctetMask; xIP >>= BitsInOneOctet;                            // Grab the a2 octet and shift the IP.
    a1 = xIP & LowOctetMask; xIP >>= BitsInOneOctet;                            // Grab the a1 octet and shift the IP.
    a0 = xIP & LowOctetMask;                                                    // Grab the final octet.
    GBUdbIndex RecordIndex = GBUdbRootNodeOffset;                               // Starting at the root node,
    RecordIndex = invokeAt(DataArray[RecordIndex + a0], IP, 0, Extend);         // Invoke w/ possible match outcome.
    if(isMatch(RecordIndex, IP)) {                                              // If this resulted in a match
        GBUdbRecord& Result = MatchedData(RecordIndex);                         // then we will grab the match data
        increaseIPCountIfNew(Result);                                           // and increase the IP count if it's new.
        return Result;                                                          // Then we return the result. Done!
    }
    RecordIndex = invokeAt(DataArray[RecordIndex + a1], IP, 1, Extend);         // Invode w/ possible match outcome.
    if(isMatch(RecordIndex, IP)) {                                              // If this resulted in a match
        GBUdbRecord& Result = MatchedData(RecordIndex);                         // then we will grab the match data
        increaseIPCountIfNew(Result);                                           // and increase the IP count if it's new.
        return Result;                                                          // Then we return the result. Done!
    }
    RecordIndex = invokeAt(DataArray[RecordIndex + a2], IP, 2, DoNotExtend);    // Invode w/ possible match outcome.
    if(isMatch(RecordIndex, IP)) {                                              // If this resulted in a match
        GBUdbRecord& Result = MatchedData(RecordIndex);                         // then we will grab the match data
        increaseIPCountIfNew(Result);                                           // and increase the IP count if it's new.
        return Result;                                                          // Then we return the result. Done!
    }
    GBUdbRecord& Result = DataArray[RecordIndex + a3];                          // Grab the record at the final node.
    increaseIPCountIfNew(Result);                                               // If new, increase the IP count.
    return Result;                                                              // Return the record.
}

void GBUdbDataset::save() {                                                     // Flush the GBUdb to disk.
    string TempFileName = MyFileName + ".tmp";                                  // Calculate temp and
    string BackFileName = MyFileName + ".bak";                                  // backup file names.
    ofstream dbFile;                                                            // Grab a file for writing.
    dbFile.open(TempFileName.c_str(), ios::out | ios::binary | ios::trunc);     // Open the file and truncate if present.
    dbFile.write((char*)DataArray, sizeof(GBUdbRecord) * MyArraySize);          // Write our array into the file.
    bool AllOK = dbFile.good();                                                 // Are we happy with this?
    dbFile.close();                                                             // Close the file when done to be nice.
    if(AllOK) {                                                                 // If everything appears to be ok
        unlink(BackFileName.c_str());                                           // Delete any old backup file we have
        rename(MyFileName.c_str(), BackFileName.c_str());                       // and make the current file a backup.
        rename(TempFileName.c_str(), MyFileName.c_str());                       // Then make our new file current.
    }
}

const RuntimeCheck SaneFileSizeCheck("GBUdbDataset::load():SaneFileSizeCheck(SaneGBUdbFileSizeLimit <= FileSize)");

void GBUdbDataset::load() {                                                     // Read the GBUdb from disk.

    ifstream dbFile;                                                            // Grab a file for reading.
    dbFile.open(MyFileName.c_str(), ios::in | ios::binary);                     // Open the file with the name we have.
    dbFile.seekg(0, ios::end);                                                  // Go to the end of the
    int FileSize = dbFile.tellg();                                              // file and back so we can
    dbFile.seekg(0, ios::beg);                                                  // determine it's size.

    int SaneGBUdbFileSizeLimit = (GBUdbDefaultArraySize * sizeof(GBUdbRecord)); // What is a sane size limit?
    SaneFileSizeCheck(SaneGBUdbFileSizeLimit <= FileSize);                      // File size sanity check.

    int NewArraySize = FileSize / sizeof(GBUdbRecord);                          // How many records in this file?

    if(NULL != DataArray) {                                                     // If we have an array loaded then
        delete[] DataArray;                                                     // delete the array,
        DataArray = NULL;                                                       // NULL it's pointer,
        MyArraySize = 0;                                                        // and zero it's size.
    }

    DataArray = new GBUdbRecord[NewArraySize];                                  // Allocate an array of the proper size
    MyArraySize = NewArraySize;                                                 // set the local size variable
    dbFile.read((char*)DataArray,FileSize);                                     // and read the file into the array.
    dbFile.close();                                                             // Close when done to be nice.
}

void GBUdbDataset::grow(int HowManyNodes) {                                     // Grow the DataArray.
    int NewArraySize = MyArraySize + (HowManyNodes * GBUdbRecordsPerNode);      // Calcualte the new array size.
    GBUdbRecord* NewDataArray = new GBUdbRecord[NewArraySize];                  // Allocate the new array.
    int OldArrayLessControl = MyArraySize + GBUdbControlNodeOffset;             // Include all records but no control.
    memcpy(NewDataArray, DataArray, sizeof(GBUdbRecord) * OldArrayLessControl); // Copy the old data to the new array.
    for(                                                                        // Loop through the control nodes...
      int o = MyArraySize + GBUdbControlNodeOffset,                             // o = old node index
      n = NewArraySize + GBUdbControlNodeOffset,                                // n = new node index
      c = GBUdbRecordsPerNode;                                                  // c = the record count (how many to do).
      c > 0;                                                                    // For until we run out of records,
      c--) {                                                                    // decrementing the count each time,
        NewDataArray[n].RawData = DataArray[o].RawData;n++;o++;                 // Copy the old control data.
    }
    delete[] DataArray;                                                         // Delete the old data array.
    DataArray = NewDataArray;                                                   // Swap in the new data array.
    MyArraySize = NewArraySize;                                                 // Correct the size value.
}

GBUdbIndex GBUdbDataset::newMatchRecord(unsigned int IP) {                      // Allocate a new Match record for IP.
    GBUdbIndex I = DataArray[ixMatchListRoot()].RawData;                        // Grab the root unused Match Record index.
    GBUdbRecord& R = DataArray[I];                                              // Grab the record itself and inspect it.
    if((R.RawData & GBUdbFlagsMask) != GBUdbMatchUnusedBit) {                   // Check that this looks like an
        throw MatchAllocationCorrupted();                                       // unused match record and if not throw!
    }                                                                           // If all is well then lets proceed.

    //// First, let's heal the linked list for future allocations.

    if(GBUdbMatchUnusedBit == R.RawData) {                                      // If the match record we are on is
        DataArray[ixMatchListRoot()].RawData =                                  // the last in the list then allocate
          newMatchNodeRoot();                                                   // a new MatchListNode for the next
    } else {                                                                    // allocation. However, if there are
        DataArray[ixMatchListRoot()].RawData =                                  // more records left in the list then
          (R.RawData & GBUdbMatchDataMask);                                     // set up the next node for the next
    }                                                                           // allocation.

    //// Once that's done we can use the record we have for real data.

    R.RawData = EncodedMatch(IP);                                               // Encode the match record for the IP.

    return I;                                                                   // Return the match record's index.
}

GBUdbIndex GBUdbDataset::newMatchNodeRoot() {                                   // Allocate a new Match node.
    GBUdbIndex I = newNodeRoot();                                               // Grab a new node to convert.
    int iLastMatch = GBUdbRecordsPerNode - 2;                                   // Calc the localized i for last match.
    for(int i = 0; i < iLastMatch; i+=2) {                                      // Loop through the node
        DataArray[I+i].RawData = GBUdbMatchUnusedBit | (I+i+2);                 // Build a linked list of Unused Match
        DataArray[I+i+1].RawData = GBUdbUnknown;                                // records with empty data.
    }
    DataArray[I+iLastMatch].RawData = GBUdbMatchUnusedBit;                      // The last record gets a NULL index
    DataArray[I+iLastMatch+1].RawData = GBUdbUnknown;                           // and null data to terminate the list.
    return I;                                                                   // Return the root index.
}

// doForAllRecords()
// This method uses a recursive call to doAllAtNode()
// doAllAtNode sweeps through each record in a node and processes any
// node entries through the next level (calling itself) or directly if
// the node is node3, or if it's pointing to a match record.

void GBUdbDataset::updateWorkingIP(unsigned int& WIP, int OctetValue, int Level) {  // Update the Working IP (WIP) at octet Level
    switch(Level) {
        case 0: {                                                               // For the node zero address,
            WIP = WIP & 0x00FFFFFF;                                             // Mask out the node zero bits.
            OctetValue = OctetValue << 24;                                      // Shift the octet value into position.
            WIP = WIP | OctetValue;                                             // Or the octet value bits into place.
            break;
        }
        case 1: {
            WIP = WIP & 0xFF00FFFF;                                             // Mask out the node zero bits.
            OctetValue = OctetValue << 16;                                      // Shift the octet value into position.
            WIP = WIP | OctetValue;                                             // Or the octet value bits into place.
            break;
        }
        case 2: {
            WIP = WIP & 0xFFFF00FF;                                             // Mask out the node zero bits.
            OctetValue = OctetValue << 8;                                       // Shift the octet value into position.
            WIP = WIP | OctetValue;                                             // Or the octet value bits into place.
            break;
        }
        case 3: {
            WIP = WIP & 0xFFFFFF00;                                             // Mask out the node zero bits.
            WIP = WIP | OctetValue;                                             // Or the octet value bits into place.
            break;
        }
    }
}

//// Note about doAllAtNode(). The x.x.x.0 address is skipped on purpose. This
//// is because all x.x.x.0 addresses are mapped to x.x.x.255. By skipping this
//// address and starting at x.x.x.1 in any search, we do not need to check for
//// x.x.x.0 ips that were remapped. They will simply appear at x.x.x.255.

void GBUdbDataset::doAllAtNode(                                                 // Recursively call O with all valid records.
  GBUdbIndex I,                                                                 // Input the node index.
  GBUdbOperator& O,                                                             // Input the Operator to call.
  int NodeLevel,                                                                // Input the NodeLevel.
  unsigned int WIP                                                              // Input the working IP.
  ) {
    int FirstI = (3 > NodeLevel) ? 0 : 1;                                       // Skip any x.x.x.0 addresses.
    for(int i = FirstI; i < GBUdbRecordsPerNode; i++) {                         // Loop through the slots in this node.
        GBUdbIndex RecordIndex = DataArray[I + i].Index();                      // Get the record index for this slot.
        if(GBUdbUnknown != RecordIndex) {                                       // Check that this slot is not empty.
            updateWorkingIP(WIP, i, NodeLevel);                                 // If we've got something then update the WIP.
            if(3 > NodeLevel) {                                                 // If we are working in rootward nodes:
                if(isMatch(RecordIndex)) {                                      // Check for a match record. If we have one then
                    unsigned int MatchIP = WIP & 0xFF000000;                    // build the IP for the match from the root
                    MatchIP |= (DataArray[RecordIndex].RawData & 0x00FFFFFF);   // of the WIP and the match IP data.
                    O(MatchIP, MatchedData(RecordIndex));                       // Then call the operator with the matched data.
                                                                                // If this slot is not a match record
                } else {                                                        // then it is a node address so we will
                    doAllAtNode(RecordIndex, O, NodeLevel+1, WIP);              // recurse to that node at a deeper level.
                }
            } else {                                                            // If we are working in the last node then
                O(WIP, DataArray[I + i]);                                       // call the Operator with this IP & Record.
            }                                                                   // All known data values in the last node are
        }                                                                       // actual data records after all.
    }
}

void GBUdbDataset::doForAllRecords(GBUdbOperator& O) {                          // Call O for every valid record.
    unsigned int WorkingIP = 0;                                                 // A working IP for all levels to use.
    int NodeLevel = 0;                                                          // The Node level where we start.
    doAllAtNode(GBUdbRootNodeOffset, O, NodeLevel, WorkingIP);                  // Start at the root node, level 0.
}

//// GBUdb Implementations /////////////////////////////////////////////////////

bool AlertFor(int count) {                                                      // True if an alert is needed.
    return (                                                                    // We want an alert whenever a count
      0x00000001 == count ||                                                    // hits any of these thresholds. Each
      0x00000002 == count ||                                                    // threshold is a new bit position
      0x00000004 == count ||                                                    // indicating that the count has
      0x00000008 == count ||                                                    // achieved a new power of 2. This
      0x00000010 == count ||                                                    // mechanism insures that newer IPs
      0x00000020 == count ||                                                    // get lots of attention while long
      0x00000040 == count ||                                                    // standing IPs still get visited
      0x00000080 == count ||                                                    // from time to time as their activity
      0x00000100 == count ||                                                    // continues.
      0x00000200 == count ||
      0x00000400 == count ||
      0x00000800 == count ||
      0x00001000 == count ||
      0x00002000 == count ||
      0x00004000 == count
    );
}

char* getTimestamp(char* TimestampBfr) {                                        // Creates an ISO GMT timestamp.

    time_t rawtime;                                                             // Get a timer and
    tm * gmt;                                                                   // a time structure.
    time(&rawtime);                                                             // Grab the current time and
    gmt=gmtime(&rawtime);                                                       // convert it to GMT.

    (void) snprintf(TimestampBfr,UTCBufferSize, "%04d%02d%02d%02d%02d%02d", // Format yyyymmddhhmmss
      gmt->tm_year+1900,
      gmt->tm_mon+1,
      gmt->tm_mday,
      gmt->tm_hour,
      gmt->tm_min,
      gmt->tm_sec
    );

    return TimestampBfr;
}

char* getIPString(unsigned int IP, char* bfr) {                                 // Converts an IP to a string.
    int a0, a1, a2, a3;                                                         // We will break the IP into 4 octets.
    const int LowOctetMask = 0x000000FF;                                        // Mask for seeing the low octet.
    const int BitsInOneOctet = 8;                                               // Number of bits to shift per octet.
    a3 = IP & LowOctetMask; IP >>= BitsInOneOctet;                              // Grab the a3 octet and shift the IP.
    a2 = IP & LowOctetMask; IP >>= BitsInOneOctet;                              // Grab the a2 octet and shift the IP.
    a1 = IP & LowOctetMask; IP >>= BitsInOneOctet;                              // Grab the a1 octet and shift the IP.
    a0 = IP & LowOctetMask;                                                     // Grab the final octet.
    sprintf(bfr,"%d.%d.%d.%d",a0,a1,a2,a3);
    return bfr;
}

void GBUdb::recordAlertFor(unsigned int IP, GBUdbRecord& R, unsigned int C) {   // Record an alert event for R if needed.
    if(AlertFor(C)) {                                                           // If an alert is needed at this level...
        GBUdbAlert NewAlert;                                                    // Create a new alert record.
        NewAlert.IP = IP;                                                       // Assign the IP.
        NewAlert.R = R;                                                         // Assign the Record.
        ScopeMutex JustMe(AlertsMutex);                                         // Lock the alerts list mutex.
        MyAlerts.push_back(NewAlert);                                           // Add our new alert to the list.
    }
}

GBUdbAlert::GBUdbAlert() :                                                      // Default constructor gets timestamp.
  IP(0) {                                                                       // IP to zero, R will init to zero
    getTimestamp(UTC);                                                          // on it's own... Get timestamp.
}

string GBUdbAlert::toXML() {                                                    // Convert this alert to XML text
    stringstream Alert;                                                         // We'll use a stringstream.

    const char* FlagName = "ERROR";                                             // We will want the Flag as text.
    switch(R.Flag()) {                                                          // Switch on the Flag() value.
        case Good:   { FlagName = "Good"; break; }                              // Convert each value to it's name.
        case Bad:    { FlagName = "Bad"; break; }
        case Ugly:   { FlagName = "Ugly"; break; }
        case Ignore: { FlagName = "Ignore"; break; }
    }

    char IPStringBfr[20];                                                       // We need a buffer for our IP.

    Alert
      << "<gbu time=\'" << UTC                                                  // GBU alert + timestamp followed
      << "\' ip=\'" << getIPString(IP,IPStringBfr)                              // with the IP,
      << "\' t=\'" << FlagName                                                  // the type flag,
      << "\' b=\'" << R.Bad()                                                   // the bad count,
      << "\' g=\'" << R.Good()                                                  // and the good count.
      << "\'/>";                                                                // That's the end.

    return Alert.str();                                                         // Return the string.
}

//// Alert import and export - for sharing data between nodes.

void GBUdb::GetAlerts(list<GBUdbAlert>& ListToFill) {                           // Get all current alerts & clear;
    ListToFill.clear();                                                         // Clear out the list to fill.
    ScopeMutex JustMe(AlertsMutex);                                             // Lock for a moment.
    ListToFill = MyAlerts;                                                      // Copy our alerts to the new list.
    MyAlerts.clear();                                                           // Clear our alerts.
}

// In order to allow gbudb nodes to interact without swamping their individuality,
// the default mode for integrating thier data is to represent the remote peer's
// influence on a logarithmic scale.

unsigned int rescaleGBUdbCount(unsigned int C) {                                // Rescale count C for integration.
    if(C < 0x00000001) { return 0; } else                                       // Log2, really, .. the short way.
    if(C < 0x00000002) { return 1; } else                                       // How many significant bits are in
    if(C < 0x00000004) { return 2; } else                                       // the number. Put another way, what
    if(C < 0x00000008) { return 3; } else                                       // power of 2 is required to for
    if(C < 0x00000010) { return 4; } else                                       // this number.
    if(C < 0x00000020) { return 5; } else
    if(C < 0x00000040) { return 6; } else
    if(C < 0x00000080) { return 7; } else
    if(C < 0x00000100) { return 8; } else
    if(C < 0x00000200) { return 9; } else
    if(C < 0x00000400) { return 10; } else
    if(C < 0x00000800) { return 11; } else
    if(C < 0x00001000) { return 12; } else
    if(C < 0x00002000) { return 13; } else
    if(C < 0x00004000) { return 14; } else
    return 15;
}

void GBUdb::ImportAlerts(list<GBUdbAlert>& PeerAlerts) {                        // Integrate peer alerts using log2.
    list<GBUdbAlert>::iterator iA;
    for(iA = PeerAlerts.begin(); iA != PeerAlerts.end(); iA++) {                // Go through the list of PeerAlerts.
        GBUdbRecord R = (*iA).R;                                                // Grab the Record in this alert.
        R.Bad(rescaleGBUdbCount(R.Bad()));                                      // Adjust the bad and good counts
        R.Good(rescaleGBUdbCount(R.Good()));                                    // for integration.
        adjustCounts((*iA).IP, R);                                              // Adjust the local counts w/ R.
    }
}

//// doForAllRecords
//// This method handles GBUdbOperators and their locking semantics.
//// For full dataset locking the mutex is acquired before calling the
//// dataset's doForAllRecords(). For record locking, the O passed to
//// this method is wrapped in a record locking shim (below) and that is
//// passed to the dataset. If None is selected then the Operator is
//// passed to the dataset as is -- assuming that the Operator will handle
//// it's own locking as needed.

class GBUdbRecordLockingShim : public GBUdbOperator {                           // Record locking shim for doForAllRecords.

  private:

    GBUdbOperator& MyOperator;                                                  // Reference the Operator we will be servicing.
    Mutex& MyMutex;                                                             // Reference the Mutex for the GBUdb we are in.

  public:

    GBUdbRecordLockingShim(GBUdbOperator& O, Mutex& M) :                        // On construction we grab our critical pieces.
      MyOperator(O),
      MyMutex(M) {
    }

    GBUdbRecord& operator()(unsigned int IP, GBUdbRecord& R) {                  // When our operator() is called
        ScopeMutex JustMe(MyMutex);                                             // we lock the mutex in scope and
        return MyOperator(IP, R);                                               // call the Operator we're servicing.
    }                                                                           // When we leave scope we unlock (see above).
};

void GBUdb::doForAllRecords(GBUdbOperator& O, GBUdbLocking L) {                 // Calls O(IP, Record) w/Every record.
    if(Dataset == L) {                                                          // If we are locking for the Dataset, then
        ScopeMutex JustMe(MyMutex);                                             // we will lock the mutex during this
        MyDataset->doForAllRecords(O);                                          // entire operation.
    } else
    if(Record == L) {                                                           // If we are locking per record then
        GBUdbRecordLockingShim X(O, MyMutex);                                   // we create a record locking shim instance
        MyDataset->doForAllRecords(X);                                          // and call O() through that.
    } else {                                                                    // If locking is NOT enabled, then
        MyDataset->doForAllRecords(O);                                          // we will call O() without any locking.
    }
}

//// The saveSnapshot() method allows us to save a snapshot of our dataset
//// while keeping the mutex locked for as short a time as possible: Just long
//// enough to make a copy of the dataset in RAM.

void GBUdb::saveSnapshot() {                                                    // Saves a snapshot of the current db.
    GBUdbDataset* Snapshot = NULL;                                              // We need a pointer for our snapshot.
    if(NULL == MyDataset) {                                                     // If we do not have a dataset to copy
        return;                                                                 // then we simply return.
    } else {                                                                    // If we do have a Dataset to copy...
        ScopeMutex JustMe(MyMutex);                                             // Lock the mutex and
        Snapshot = new GBUdbDataset(*MyDataset);                                // make a copy in memory.
    }                                                                           // Then we can unlock the mutex.
    Snapshot->save();                                                           // Then outside the mutex we can save.
    delete Snapshot;                                                            // Once saved we can delete the snapshot.
    PostsCounter = 0;                                                           // Reset the posts counter.
}

//// reduce()
//// Using the doForAllRecords() functionality, this method reduces all counts
//// by 2 thus renormalizing all records at lower count values. Unknown flagged
//// records who's counts drop to zero will achieve the state GBUdbUnknown. As
//// such, those values would not be carried over in a compress() operation.

class ReduceAll : public GBUdbOperator {                                        // To reduce the good and bad counts.
  public:
    GBUdbRecord& operator()(unsigned int IP, GBUdbRecord& R) {                  // Given each record,
        R.Good(R.Good() >> 1);                                                  // Reduce the Good count by half.
        R.Bad(R.Bad() >> 1);                                                    // Reduce the Bad count by half.
        return R;                                                               // Return the record.
    }
} ReduceAllOperator;

void GBUdb::reduce() {                                                          // Reduce all counts by half.
    doForAllRecords(ReduceAllOperator);                                         // Call do for all records with the
}                                                                               // ReduceAllOperator.

//// compress()
//// Using the doForAllRecords() functionality, this method creates a temporary
//// dataset, copies the existing data into that dataset except where the data
//// is GBUdbUnknown, and then swaps the new dataset in place of the old.

class CompressAll : public GBUdbOperator {
  private:

    GBUdbDataset* MyOldDataset;                                                 // Where do we find the old dataset.
    GBUdbDataset* MyNewDataset;                                                 // Where do we store our new dataset.

    int CountConverted;
    int CountDropped;

  public:

    // Note - There is no destructor. It is expected that the calling function
    // will extract the NewDataset and replace the OldDataset when the operation
    // has been successful.

    CompressAll(GBUdbDataset* OldDataset) :                                     // Startup by
      MyOldDataset(OldDataset),                                                 // Grabbing the old dataset,
      MyNewDataset(NULL),                                                       // The new one isn't there yet.
      CountConverted(0),                                                        // Converted and Dropped
      CountDropped(0) {                                                         // Counts are zero.
        MyNewDataset = new GBUdbDataset(NULL);                                  // Allocate a new Dataset.
        MyNewDataset->FileName(OldDataset->FileName());                         // Set it's name the same as the old.
    }                                                                           // We don't want to Load() it that way ;-)

    GBUdbRecord& operator()(unsigned int IP, GBUdbRecord& R) {                  // The ForAll Operator goes like this...
        if(GBUdbUnknown != R.RawData) {                                         // If the record is not GBUdbUnknown then
            MyNewDataset->invokeRecord(IP).RawData = R.RawData;                 // invoke it and copy it's data.
            ++CountConverted;                                                   // Increment the converted count.
        } else {                                                                // If the record is GBUdbUnknown then
            ++CountDropped;                                                     // count it as dropped and forget it.
        }
        return R;                                                               // Return the record reference.
    }

    GBUdbDataset* Old() {return MyOldDataset;}                                  // Here we can get our OldDataset pointer.
    GBUdbDataset* New() {return MyNewDataset;}                                  // Here we can get our NewDataset pointer.
    int Converted() {return CountConverted;}                                    // Here we can get the converted count.
    int Dropped() {return CountDropped;}                                        // Here we can get the dropped count.
};

void GBUdb::compress() {                                                        // Remove any unknown records (reduced to zero).
    CompressAll BuildCompressedDataset(MyDataset);                              // Create a CompressAll operator for this dataset.
    ScopeMutex Freeze(MyMutex);                                                 // Lock the mutex for the rest of this operation.
    MyDataset->doForAllRecords(BuildCompressedDataset);                         // Copy all of the active data records.
    MyDataset = BuildCompressedDataset.New();                                   // Put the new dataset in place.
    delete BuildCompressedDataset.Old();                                        // Delete the old dataset.
}                                                                               // All done, so we're unlocked.

int GBUdb::readIgnoreList(const char* FileName) {                               // setIgnore for a list of IPs
    int IPCount = 0;                                                            // Keep track of the IPs we read.
    try {                                                                       // Capture any exceptions.
        char IPLineBuffer[256];                                                 // Create a line buffer.
        const int SafeBufferSize = sizeof(IPLineBuffer) - 1;                    // Safe size always leaves a NULL on the end.
        ifstream ListFile(FileName, ios::in);                                   // Open up the list file.
        while(ListFile.good()) {                                                // While we've got a good file (not eof)
            memset(IPLineBuffer, 0, sizeof(IPLineBuffer));                      // Clear the buffer.
            ListFile.getline(IPLineBuffer, SafeBufferSize);                     // Read the line. (safely NULL terminated)

            // Now we have an IP on a line (in theory). We will parse
            // the ip and process any that parse correctly.
            // First eat anything that's not a digit.

            unsigned long IP = 0L;                                              // We need an IP buffer.
            char* cursor = IPLineBuffer;                                        // Start on the first byte.

            if('#' == *cursor) continue;                                        // Lines that start with # are comments.
            while(0 < *cursor && isspace(*cursor)) ++cursor;                    // Eat any leading spaces.

            // First octet.

            if(!isdigit(*cursor)) continue;                                     // If it's not a digit skip this line.
            if(255 < atoi(cursor)) continue;                                    // If the octet is out of range skip!
            IP += atoi(cursor); IP <<= 8;                                       // Grab the first int and shift it.
            while(isdigit(*cursor)) ++cursor;                                   // Eat those digits.
            if('.'!=(*cursor)) continue;                                        // If we don't find a dot skip this line.
            ++cursor;                                                           // If we do, skip the dot.

            // Second octet.

            if(!isdigit(*cursor)) continue;                                     // If we're not at digit skip this line.
            if(255 < atoi(cursor)) continue;                                    // If the octet is out of range skip!
            IP += atoi(cursor); IP <<= 8;                                       // Grab the octet and shift things left.
            while(isdigit(*cursor)) ++cursor;                                   // Eat those digits.
            if('.'!=(*cursor)) continue;                                        // If we don't find a dot skip this line.
            ++cursor;                                                           // If we do, skip the dot.

            // Third octet.

            if(!isdigit(*cursor)) continue;                                     // If we're not at digit skip this line.
            if(255 < atoi(cursor)) continue;                                    // If the octet is out of range skip!
            IP += atoi(cursor); IP <<= 8;                                       // Grab the octet and shift things left.
            while(isdigit(*cursor)) ++cursor;                                   // Eat those digits.
            if('.'!=(*cursor)) continue;                                        // If we don't find a dot skip this line.
            ++cursor;                                                           // If we do, skip the dot.

            // Last octet.

            if(!isdigit(*cursor)) continue;                                     // If we're not at a digit skip this line.
            if(255 < atoi(cursor)) continue;                                    // If the octet is out of range skip!
            IP += atoi(cursor);                                                 // Grab the octet. IP finished!

            setIgnore(IP);                                                      // Set the IP to Ignore.
            ++IPCount;                                                          // Bump the IP count.

        }
        ListFile.close();
    }
    catch(...) { }                                                              // If we have an exception we stop.
    return IPCount;                                                             // Always return the number of lines read.
}

}