Cpp > Programs

cpp BTree example

#include "btree.hpp"
#include <Windows.h>
#include <iostream.h>
#include <stdlib.h>

// static definitions
DiskManager BTree::theDiskManager;
DataFile BTree::theDataFile;
WNJFile BTree::theWNJFile;

int WNJFile::myCount =      0L;
int Page::gPage =           1;
int BTree::NodeIndexCtr =   0;
int BTree::LeafIndexCtr =   0;
int BTree::NodePageCtr =    0;
int BTree::LeafPageCtr =    0;
int BTree::NodeIndexPerPage[Order+1];
int BTree::LeafIndexPerPage[Order+1];

// prototypes
void parseCommandLines(char *buffer,int argc,char **argv);
void ShowMenu(long*);
void DoFind(char*, BTree&);
void ParseFile(BTree&);

// driver program
int main()
{
   BTree myTree;

   for (int i = 0; i < Order +1; i++)
   {
      BTree::NodeIndexPerPage[i] = 0;
      BTree::LeafIndexPerPage[i] = 0;
   }

   char buffer[PageSize+1];

   bool fQuit = false;

   while ( !fQuit )
   {
       cout << "?: ";
       cin.getline(buffer,PageSize);

       if ( buffer[0] == '-' )
       {
           switch (buffer[1])
           {
             case '?':
                DoFind(buffer+2,myTree);
                break;

             case '!':
                   myTree.PrintTree();
                   break;

             case 'F':
             case 'f':
                   ParseFile(myTree);
                   break;
             case '0':
                 fQuit = true;
                 break;
          }
       }
       else
       {
          if ( myTree.Insert(buffer) )
            cout << "Inserted.\n";
          buffer[0] = '\0';
       }
   }
       return 0;
}

// having found matches, show the menu of choices
// each entry is numbered and dated
void ShowMenu(int *list)
{
  int j=0;
  char buffer[PageSize+1];
  time_t theTime;
  int len;
  char listBuff[256];
  struct tm * ts;
  int dispSize;

  while (list[j] && j < 20)
  {
     BTree::theDataFile.GetRecord(list[j],buffer,len, theTime);
  dispSize = __min(len,32);
     strncpy(listBuff,buffer,dispSize);
     if (dispSize == 32)
        {
        listBuff[29] = '.';
        listBuff[30] = '.';
        listBuff[31] = '.';
        }
     listBuff[dispSize]='\0';
     ts = localtime(&theTime);
     cout << "[" << (j+1) << "] ";
     cout << ts->tm_mon << "/";
     cout << ts->tm_mday << "/";
     cout << ts->tm_year << " ";
     cout <<  listBuff << endl;
     j++;
  }
}

// handle -? command
// find matches, show the menu, request choice
// display record and redisplay menu
void DoFind(char * searchString, BTree& myTree)
{

    // create an array of total set of WNJ
    // offsets. This will be used to display
    // choices and to find actual text
    int list[PageSize];

    // initialize the array to all zeros
    for (int i = 0; i<PageSize; i++)
    list[i] = 0;

    int k = 0;

    char * p1 = searchString;
    while (p1[0] == ' ')
        p1++;

    int offset = myTree.Find(p1);
    if (offset)
    {
        // get the array of offsets from WNJFile
        int *found  =  BTree::theWNJFile.Find(offset);
        int j = 0;

        // add any you don't already have
        for (;k < PageSize && found[j];j++,k++)
        {
            for (int l = 0; l < k; l++)
            {
                if (list[l] == found[j])
                    continue;
            }
            list[k] = found [j];
        }
        delete [] found;
    }

    cout << "\n";

    if (!list[0])
    {
        cout << "Nothing found.\n";
        return;
    }

    ShowMenu(list);

    int choice;
    char buffer[PageSize];
    int len;
    time_t theTime;

    for (;;)
    {
        cout << "Choice (0 to stop): " ;
        cin >> choice;
        cin.ignore(PageSize,'\n');
        if ( choice < 1 )
            break;

        BTree::theDataFile.GetRecord(list[choice-1],buffer,len, theTime);
        cout << "\n>> ";
        cout << buffer;
        cout << "\n\n";
        ShowMenu(list);
    }
}

// open a file and create a new note for each line
// index every word in the line
void ParseFile( BTree& myTree)
{

    char fileName[256];
    cout << "FileName: ";
    cin.getline(fileName,PageSize);

    char buffer[PageSize];
    char theString[PageSize];

    ifstream theFile(fileName,ios::in );
    if (!theFile)
    {
        cout << "Error opening input file " << fileName << endl;
        return;
    }

    int offset = 0;
    for (;;)
    {
        theFile.read(theString,PageSize);
        int len = theFile.gcount();
        if (!len)
           break;
        theString[len]='\0';
        char *p1, *p2, *p0;
        p0 = p1 = p2 = theString;

        while (p1[0] && (p1[0] == '\n' || p1[0] == '\r'))
           p1++;

        p2 = p1;

        while (p2[0] && p2[0] != '\n' && p2[0] != '\r')
           p2++;

        int bufferLen = p2 - p1;
        int totalLen = p2 - p0;

        if (!bufferLen)
           continue;

        // lstrcpyn(buffer,p1,bufferLen);
        strncpy(buffer,p1,bufferLen);
        buffer[bufferLen]='\0';

        // for (int i = 0; i< PageSize; i++)
           cout << "\r";
        cout << "Parsing " << buffer;
        myTree.Insert(buffer);
        offset += totalLen;
        theFile.clear();
        theFile.seekg(offset,ios::beg);
    }
    cout << "\n\nCompleted parsing " << fileName << endl;
}