IntVecFile.cc

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// -*- C++ -*-

// PLearn (A C++ Machine Learning Library)
// Copyright (C) 1998 Pascal Vincent
// Copyright (C) 1999-2002 Pascal Vincent, Yoshua Bengio and University of Montreal
//

// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
// 
//  1. Redistributions of source code must retain the above copyright
//     notice, this list of conditions and the following disclaimer.
// 
//  2. Redistributions in binary form must reproduce the above copyright
//     notice, this list of conditions and the following disclaimer in the
//     documentation and/or other materials provided with the distribution.
// 
//  3. The name of the authors may not be used to endorse or promote
//     products derived from this software without specific prior written
//     permission.
// 
// THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR
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// OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN
// NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// 
// This file is part of the PLearn library. For more information on the PLearn
// library, go to the PLearn Web site at www.plearn.org


 

/* *******************************************************      
   * $Id: IntVecFile.cc,v 1.6 2004/07/21 16:30:51 chrish42 Exp $
   * AUTHORS: Pascal Vincent
   * This file is part of the PLearn library.
   ******************************************************* */

#include "IntVecFile.h"
//#include "fileutils.h"
#include <plearn/base/byte_order.h>

namespace PLearn {
using namespace std;

const char IntVecFile::signature[] = {
  0xDE, 0xAD, 0xBE, 0xEF, 0x00               
};

const int IntVecFile::header_size[] = {      
  0,                                         
  2                                          
};


IntVecFile::IntVecFile(const IntVecFile& other)
  : filename(other.filename), f(0), length_(other.length_),
    version_number_(other.version_number_), endianness_(other.endianness_)
{
  open(filename, false /* readonly */);
}

void IntVecFile::open(const string& the_filename, bool readwrite)
{
  if(f)
    close();

  filename = the_filename;
  bool file_exists = isfile(filename);
  if(readwrite)
  {
    f = fopen(filename.c_str(),"a+");
    if(!f)
      PLERROR("Couldn't open file %s for read/write",filename.c_str());
  }
  else
  {
    f = fopen(filename.c_str(),"r");
    if(!f)
      PLERROR("Couldn't open file %s for reading",filename.c_str());
  }
  if (file_exists)
    getVersionAndSize();
  else
    writeFileSignature();
}

int IntVecFile::get(int i) const
{
#ifdef BOUNDCHECK
  if(i<0 || i>=length())
    PLERROR("Out Of Bounds in IntVecFile::get");
#endif
  seek_to_index(i);
  return fread_int(f, endianness_ == BIG_ENDIAN_ORDER);
}

void IntVecFile::put(int i, int value)
{
  seek_to_index(i);
  fwrite_int(f, value, endianness_ == BIG_ENDIAN_ORDER);
  if(i>=length_)
    length_ = i+1;
}

void IntVecFile::close()
{
  if(f)
    fclose(f);
  f=0;
}

IntVecFile::~IntVecFile()
{
  close();
}

TVec<int> IntVecFile::getVec() const
{
  int tt;
  TVec<int> res(length());
  seek_to_index(0);
  if((tt=fread(res.data(), sizeof(int), length(), f)) != length())
    PLERROR("fread error in IntVecFile::getVec()");

  // Switch byte order if necessary
  if (byte_order() != endianness_)
    endianswap(res.data(), length());

  return res;
}
void IntVecFile::append(const TVec<int>& vec)
{
  seek_to_index(length());

  if (byte_order() != endianness_) {
    TVec<int> new_vec(vec.length());
    new_vec << vec;
    endianswap(new_vec.data(), new_vec.length());
    fwrite(new_vec.data(), sizeof(int), new_vec.length(), f);
  }
  else {
    fwrite(vec.data(), sizeof(int), vec.length(), f);
  }

  length_ += vec.length();
}

void IntVecFile::writeFileSignature()
{
  // This is for a new file.  Assume length 0, version number 1,
  // file endianness is current-platform endianness
  length_ = 0;
  version_number_ = 1;
  endianness_ = byte_order();

  fseek(f, 0, SEEK_SET);
  fputs(signature, f);                       
  fputc(endianness_, f);
  fputc(0x00, f);
  fputc(0x00, f);
  fputc(char(version_number_), f);
}

void IntVecFile::getVersionAndSize()
{
  if (sizeof(int) != 4)
    PLERROR("IntVecFile::getVersionAndSize: "
            "IntVecFile not yet designed to handle sizeof(int) != 4");
  
  long the_filesize = filesize(filename);
  if (the_filesize < long(2*sizeof(int)) /* assume 4 */)
    goto version0;                           // unbelievable but true!

  fseek(f, 0, SEEK_SET);
  for (int i=0; i<4; ++i)
    if (char(fgetc(f)) != signature[i])
      goto version0;                         

  // Assume new-world file format
  endianness_ = char(fgetc(f));
  if (endianness_ != LITTLE_ENDIAN_ORDER &&
      endianness_ != BIG_ENDIAN_ORDER)
    PLERROR("IntVecFile::getVersionAndSize: "
            "File format error in file %s Only supported endianness is 'L' or 'B'\n"
            "Read %c", filename.c_str(),endianness_);

  if(fgetc(f) != 0x00 || fgetc(f) != 0x00)
    PLERROR("IntVecFile::getVersionAndSize: "
            "File format error in file %s", filename.c_str());

  version_number_ = (unsigned char)fgetc(f);

  if (version_number_ > 1)
    PLERROR("IntVecFile::getVersionAndSize: "
            "File version (%d) is not supported", version_number_);

  length_ = the_filesize / sizeof(int) - header_size[version_number_];
  return;

 version0:
  length_ = the_filesize / sizeof(int);
  version_number_ = 0;
  endianness_ = 'L';
}

void IntVecFile::seek_to_index(int i) const
{
  fseek(f, (i+header_size[version_number_]) * sizeof(int), SEEK_SET);
}

} // end of namespace PLearn

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