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File indexing completed on 2025-08-03 08:20:34

 //
 // fileEventIterator   mlp 4/19/1997
 //
 // this iterator reads events froma data file. 
 
 
 #include <stddef.h>
 #include <string.h>
 
 #include <unistd.h>
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <fcntl.h>
 
 // there are two similar constructors, one with just the
 // filename, the other with an additional status value
 // which is non-zero on return if anything goes wrong. 
 #include "fileEventiterator.h"
 
 //#ifndef LVL2_WINNT
 #include "lzobuffer.h"
 //#endif
 
 
 fileEventiterator::~fileEventiterator()
 {
      if (fd) close (fd);
      if (thefilename != NULL) delete [] thefilename;
      if (bp != NULL ) delete [] bp;
      if (bptr != NULL ) delete bptr;
 }  
 
 
 fileEventiterator::fileEventiterator(const char *filename)
 {
   open_file ( filename);
 }  
 
 fileEventiterator::fileEventiterator(const char *filename, int &status)
 {
   status =  open_file ( filename);
 }
 
 
 int fileEventiterator::open_file(const char *filename)
 {
   fd  = open (filename, O_RDONLY | O_LARGEFILE);
   bptr = 0;
   bp = 0;
   allocatedsize = 0;
   thefilename = NULL;
   events_so_far = 0;
   verbosity=0;
   _defunct = 0;
 
   if (fd > 0) 
     {
       thefilename = new char[strlen(filename)+1];
       strcpy (thefilename, filename);
       last_read_status = 0;
       current_index = 0;
       return 0;
     }
   else
     {
       last_read_status = 1;
       _defunct = 1;
     }
   return 1;
 
 }
 
 
 
 void fileEventiterator::identify (OSTREAM &os) const
 { 
   os << "fileEventiterator reading from " << thefilename;
   if ( _defunct ) os << " *** defunct";
   os<< std::endl;
 
 };
 
 
 const char * fileEventiterator::getCurrentFileName() const
 { 
   static char namestr[512];
   if ( thefilename == NULL)
     {
       return " ";
     }
   else
     {
       strcpy (namestr, thefilename);
       return namestr;
     }
 };
 
 
 
 
 const char *  fileEventiterator::getIdTag () const
 { 
   //  sprintf (idline, " -- fileEventiterator reading from %s", thefilename);
   return "fileEventiterator";
 };
 
 
 
 // and, finally, the only non-constructor member function to
 // retrieve events from the iterator.
 
 Event * fileEventiterator::getNextEvent()
 {
   if ( _defunct ) return 0;
   Event *evt = 0;
 
   // if we had a read error before, we just return
   if (last_read_status) return NULL;
 
   // see if we have a buffer to read
   if (bptr == 0) 
     {
       if ( (last_read_status = read_next_buffer()) !=0 )
     {
       return NULL;
     }
     }
 
   while (last_read_status == 0)
     {
       if (bptr) evt =  bptr->getEvent();
       if (evt) 
     {
       //evt->setOriginBuffer(bptr->getBufferSequence());
       events_so_far++;
       return evt;
     }
       last_read_status = read_next_buffer();
     }
 
   return NULL;
 
 }
 
 // -----------------------------------------------------
 // this is a private function to read the next buffer
 // if needed. 
 
 int fileEventiterator::read_next_buffer()
 {
   PHDWORD initialbuffer[BUFFERBLOCKSIZE/4];
 
   buffer_size = 0;
   
   if (bptr) 
     {
       delete bptr;
       bptr = 0;
     }
   events_so_far = 0;
     
   // we are now reading the first block (8192 bytes) into
   // initialbuffer. The buffer is at least that long. We
   // look up the buffersize etc from that, and 
   // start filling the actual buffer. We do not read 
   // the data into the eventual destination since we may 
   // have to delete it to get more room (we might find that
   // the buffer is larger than what we have allocated).
 
 
   // set the pointer to char to the destination buffer
   char *cp = (char *) initialbuffer;
 
   unsigned int xc;
 
 
   // this while loop implements the skipping of 8k records until
   // we find a valid buffer marker. (We usually find it right away). 
  
   while (buffer_size == 0 )
     {  
       // read the first record
       xc = read ( fd, cp, BUFFERBLOCKSIZE);
       
       // error of EoF?
       if ( xc < BUFFERBLOCKSIZE  ) 
     {
       //      COUT << "ferror" << std::endl;
       return -1;
     }
 
 
       // get the buffer length into a dedicated variable
       if (initialbuffer[1] == BUFFERMARKER || initialbuffer[1]== GZBUFFERMARKER 
       ||  initialbuffer[1]== LZO1XBUFFERMARKER 
       || initialbuffer[1]== LZO1CBUFFERMARKER 
       || initialbuffer[1]== LZO2ABUFFERMARKER 
       || initialbuffer[1]== BZ2BUFFERMARKER 
       || initialbuffer[1]== ONCSBUFFERMARKER) 
     {
       buffer_size = initialbuffer[0];
     }
       else
     {
       unsigned int  marker = buffer::u4swap(initialbuffer[1]);
       if (marker == BUFFERMARKER 
           || marker == GZBUFFERMARKER 
           || marker ==  LZO1XBUFFERMARKER 
           || marker ==  LZO1CBUFFERMARKER 
           || marker ==  LZO2ABUFFERMARKER 
           || marker ==  BZ2BUFFERMARKER 
           || marker == ONCSBUFFERMARKER)
         {
           buffer_size = buffer::u4swap(initialbuffer[0]);
         }
     }
     }
 
 
   int i;
   if (bp) 
     {
       // this tests if we have enough space in the existing buffer
       if  (buffer_size > allocatedsize*4)   // no, we delete and make a bigger one
     {
       delete [] bp;
       i = (buffer_size +BUFFERBLOCKSIZE-1) /BUFFERBLOCKSIZE;
       allocatedsize = i * BUFFERBLOCKSIZE/4;
       bp = new PHDWORD[allocatedsize];
       //  std::cout << __FILE__ << "  " << __LINE__ << " new bp pointer is " << bp << "  length value "  << bp[-1]<< std::endl;
     }
     }
   else
     {
       i = (buffer_size +BUFFERBLOCKSIZE-1) /BUFFERBLOCKSIZE;
       allocatedsize = i * BUFFERBLOCKSIZE/4;
       bp = new PHDWORD[allocatedsize];
 
     }
 
   //  for (i = 0; i<BUFFERBLOCKSIZE/4; i++ ) bp[i] = initialbuffer[i];
   memcpy ( bp, initialbuffer, BUFFERBLOCKSIZE);
  
   cp = (char *) bp;
 
   // and update the destination buffer pointer
   cp += BUFFERBLOCKSIZE;
 
   PHDWORD read_so_far =  BUFFERBLOCKSIZE;
 
   int errorinread=0;
 
   // we calculate how many BUFFERBLOCKSIZE-sized records we need to read
   // we have already one, so this is the number of records -1.
   // normally we would round up  (buffer_size + BUFFERBLOCKSIZE -1) /BUFFERBLOCKSIZE
   int records_to_read =  (buffer_size -1) /BUFFERBLOCKSIZE;
   unsigned int bytes_to_read   =  records_to_read * BUFFERBLOCKSIZE;
   
   xc = read ( fd, cp, bytes_to_read);
   if ( xc < bytes_to_read ) 
     {
       COUT << "error in buffer, salvaging" << std::endl;
       bp[0] = read_so_far + xc; 
       errorinread =1;
     }
 
   // and initialize the current_index to be the first event
 
   if ( ( initialbuffer[1]== GZBUFFERMARKER 
      || buffer::u4swap(initialbuffer[1])== GZBUFFERMARKER 
      || initialbuffer[1]== LZO1XBUFFERMARKER 
      || buffer::u4swap(initialbuffer[1])== LZO1XBUFFERMARKER 
      || initialbuffer[1]== LZO1CBUFFERMARKER 
      || buffer::u4swap(initialbuffer[1])== LZO1CBUFFERMARKER
      || initialbuffer[1]== LZO2ABUFFERMARKER 
      || buffer::u4swap(initialbuffer[1])== LZO2ABUFFERMARKER )
        && errorinread  )
     {
       bptr = 0;
       return -3;
     }
 
   return buffer::makeBuffer( bp, allocatedsize, &bptr);
 
 
 }
 

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