tdataseqascii.c

Solaris环境下的数据挖掘算法：birch聚类算法。该算法适用于对大量数据的挖掘。

/*
  ========================================================================
  DEVise Data Visualization Software
  (c) Copyright 1992-1996
  By the DEVise Development Group
  Madison, Wisconsin
  All Rights Reserved.
  ========================================================================

  Under no circumstances is this software to be copied, distributed,
  or altered in any way without prior permission from the DEVise
  Development Group.
*/

/*
  $Id: TDataSeqAscii.c,v 1.4 1996/12/03 20:31:34 jussi Exp $

  $Log: TDataSeqAscii.c,v $
  Revision 1.4  1996/12/03 20:31:34  jussi
  Updated to reflect new TData interface.

  Revision 1.3  1996/11/25 18:15:15  wenger
  Changes to non-indexed attrproj to match other changes to TData;
  changes to compile non-index attrproj and to get the rest of Devise
  to compile with that.

  Revision 1.2  1996/11/22 20:41:14  flisakow
  Made variants of the TDataAscii classes for sequential access,
  which build no indexes.

  ReadRec() method now returns a status instead of void for every
  class that has the method.
 
*/

//#define DEBUG

#include <iostream.h>
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <limits.h>
#include <unistd.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>

#include "Parse.h"
#include "TDataSeqAscii.h"
#include "Exit.h"
#include "Util.h"
#include "DataSourceFileStream.h"
#include "DataSourceSegment.h"
#include "DataSourceTape.h"
#include "DataSourceBuf.h"
#include "DevError.h"
#include "DataSeg.h"
#include "QueryProc.h"
#include "DevError.h"

#ifdef ATTRPROJ
#   include "ApInit.h"
#else
#   include "Init.h"
#   include "DataSourceWeb.h"
#endif

# define  _STREAM_COMPAT

static const int INDEX_ALLOC_INC = 10000; // allocation increment for index
static const int LINESIZE = 4096;         // maximum size of each line

/* We cache the first FILE_CONTENT_COMPARE_BYTES from the file.
   The next time we start up, this cache is compared with what's in
   the file to determine if they are the same file. */

static const int FILE_CONTENT_COMPARE_BYTES = 4096;


static char fileContent[FILE_CONTENT_COMPARE_BYTES];
static char indexFileContent[FILE_CONTENT_COMPARE_BYTES];
static char *   srcFile = __FILE__;

TDataSeqAscii::TDataSeqAscii(char *name, char *type, char *param, int recSize)
: TData(name, type, param, recSize)
{
    DO_DEBUG(printf("TDataSeqAscii::TDataSeqAscii(0x%p)(%s, %s, %s, %d)\n",
		    this, name, type, param, recSize));
    DO_DEBUG(printf("_data = 0x%p\n", _data));

    _fileOpen = true;
    if (_data->Open("r") != StatusOk) {
	_fileOpen = false;
    }
    
    DataSeg::Set(NULL, NULL, 0, 0);
    
    _bytesFetched = 0;
    
    _lastPos = 0;
    _currPos = 0;
    _lastIncompleteLen = 0;

    _prevPos = 0;
    _prevRid = 0;

    _data->Seek(0, SEEK_SET);

    Dispatcher::Current()->Register(this, 10, AllState, false, -1);
}

TDataSeqAscii::~TDataSeqAscii()
{
#ifdef DEBUG
  printf("TDataSeqAscii destructor\n");
#endif

  if (_fileOpen)
    _data->Close();

  Dispatcher::Current()->Unregister(this);
}

Boolean TDataSeqAscii::CheckFileStatus()
{
  CheckDataSource();
  // see if file is (still) okay
  if (!_data->IsOk()) {
    // if file used to be okay, close it
    if (_fileOpen) {
      Dispatcher::Current()->Unregister(this);
      printf("Data stream %s is no longer available\n", _name);
      _data->Close();
      TData::InvalidateTData();
      _fileOpen = false;
    }
    Boolean old = DevError::SetEnabled(false);
    if (_data->Open("r") != StatusOk) {
      (void)DevError::SetEnabled(old);
      return false;
    }
    (void)DevError::SetEnabled(old);
    printf("Data stream %s has become available\n", _name);
    _fileOpen = true;
    Dispatcher::Current()->Register(this, 10, AllState, false, -1);
  }

  return true;
}

int TDataSeqAscii::Dimensions(int *sizeDimension)
{
  return 0;
}

Boolean TDataSeqAscii::HeadID(RecId &recId)
{
  recId = 0;
  return true;
}

Boolean TDataSeqAscii::LastID(RecId &recId)
{
  reportErrNosys("LastID is not valid on non-indexed TDatas");
  return false;
}

TData::TDHandle TDataSeqAscii::InitGetRecs(RecId lowId, RecId highId,
                                           Boolean asyncAllowed,
                                           ReleaseMemoryCallback *callback)
{
#if defined(DEBUG)
  cout << " RecID lowID  = " << lowId << " highId " << highId << " order = "
       << order << endl;
#endif

  TDataRequest *req = new TDataRequest;
  DOASSERT(req, "Out of memory");

  req->nextId = lowId;
  req->endId = highId;
  req->relcb = callback;

  return req;
}

Boolean TDataSeqAscii::GetRecs(TDHandle req, void *buf, int bufSize,
                               RecId &startRid, int &numRecs, int &dataSize)
{
  DOASSERT(req, "Invalid request handle");

#ifdef DEBUG
  printf("TDataSeqAscii::GetRecs buf = 0x%p\n", buf);
#endif

  numRecs = bufSize / _recSize;
  DOASSERT(numRecs, "Not enough record buffer space");

  if (req->nextId > req->endId)
    return false;
  
  int num = req->endId - req->nextId + 1;
  if (num < numRecs)
    numRecs = num;
  
  TD_Status status = ReadRec(req->nextId, numRecs, buf);
  if (status != TD_OK)
    return false;
 
  startRid = req->nextId;
  dataSize = numRecs * _recSize;
  req->nextId += numRecs;
  
  _bytesFetched += dataSize;
  
  return true;
}

void TDataSeqAscii::DoneGetRecs(TDHandle req)
{
  DOASSERT(req, "Invalid request handle");

  delete req;
}

void TDataSeqAscii::GetIndex(RecId id, int *&indices)
{
  static int index[1];
  index[0] = id;
  indices = index;
}

int TDataSeqAscii::GetModTime()
{
  if (!CheckFileStatus())
    return -1;

  return _data->GetModTime();
}

char *TDataSeqAscii::MakeIndexFileName(char *name, char *type)
{
  char *fname = StripPath(name);
  int nameLen = strlen(Init::WorkDir()) + 1 + strlen(fname) + 1;
  char *fn = new char [nameLen];
  sprintf(fn, "%s/%s", Init::WorkDir(), fname);
  return fn;
}

void TDataSeqAscii::Initialize()
{
  return;
}

void TDataSeqAscii::Checkpoint()
{
    printf("Cannot checkpoint %s\n", _name);
    return;
}


void TDataSeqAscii::InvalidateTData()
{
    TData::InvalidateTData();
}


/* Build index for the file. This code should work when file size
   is extended dynamically. Before calling this function, position
   should be at the last place where file was scanned. */

void TDataSeqAscii::BuildIndex()
{
}

/* Rebuild index */

void TDataSeqAscii::RebuildIndex()
{
}

TD_Status TDataSeqAscii::ReadRec(RecId id, int numRecs, void *buf)
{
#ifdef DEBUG
  printf("TDataSeqAscii::ReadRec %ld,%d,0x%p\n", id, numRecs, buf);
#endif

  char line[LINESIZE];
  
  char *ptr = (char *) buf;
  Boolean valid;

  for (int i = 0; i < numRecs; i++) {

    int len;

    //fprintf(stdout, "In ReadRec id: %ld  numRecs: %d\n",id,numRecs);
    if (_prevRid + 1 == id + i) {
        // We're reading sequentially, _currPos is valid.
        _prevPos = _currPos;
        _prevRid = id + i;
    } else { 
        // Handle non-sequential case (scan)
        // (Also will happen for the first read of a file.)

        if (id + i == _prevRid) {
          // They want the last record again.
          if (_data->Seek(_prevPos, SEEK_SET) < 0) {
            perror("fseek");
            DOASSERT(0, "Cannot perform file seek");
          }
          _currPos = _prevPos;

        } else if (id + i < _prevRid) {
          if (_data->Seek(0, SEEK_SET) < 0) {
            perror("fseek");
            DOASSERT(0, "Cannot perform file seek");
          }

          _prevRid = 0;
          _prevPos = 0;
          _currPos = 0;
        }

        // Now read forward to find it.
        while (id + i > _prevRid) {

            if (_data->Fgets(line, LINESIZE) == NULL)
              return TD_EOF;

            len = strlen(line);

            if (len > 0 ) {
              DOASSERT(line[len - 1] == '\n', "Data record too long");
              line[len - 1] = '\0';
            }

              // Check for a valid record
            valid = Decode(ptr, _currPos, line);
            _currPos += len;

            if (valid) {
                _prevPos = _currPos;
                _prevRid++;
            }
        }

        // We are now at the record we want.
    }

    do {
        if (_data->Fgets(line, LINESIZE) == NULL)
          return TD_EOF;

        len = strlen(line);
    
        if (len > 0 ) {
          DOASSERT(line[len - 1] == '\n', "Data record too long");
          line[len - 1] = '\0';
        }
    
        valid = Decode(ptr, _currPos, line);
        _currPos += len;

    } while (!valid);

    ptr += _recSize;
  }

  return TD_OK;
}

void TDataSeqAscii::WriteRecs(RecId startRid, int numRecs, void *buf)
{
  DOASSERT(!_data->isTape(), "Writing to tape not supported yet");
}

void TDataSeqAscii::WriteLine(void *line)
{
  DOASSERT(!_data->isTape(), "Writing to tape not supported yet");
}

void TDataSeqAscii::Cleanup()
{
  Checkpoint();

  if (_data->isTape())
    _data->printStats();
}

void TDataSeqAscii::PrintIndices()
{
}