/* Copyright (C) 2014 InfiniDB, Inc.

   This program is free software; you can redistribute it and/or
   modify it under the terms of the GNU General Public License
   as published by the Free Software Foundation; version 2 of
   the License.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
   MA 02110-1301, USA. */

/******************************************************************************
 * $Id: we_colbuf.h 4726 2013-08-07 03:38:36Z bwilkinson $
 *
 *****************************************************************************/

/** @file
 * class ColumnBuffer
 */

#pragma once

#include <cstdio>

#include "we_type.h"

namespace WriteEngine
{
class Log;
class ColumnInfo;

/** @brief A buffer class to store data written to column files
 *
 * ColumnBuffer is to be used as a temporary buffer to store Column data before
 * writing it out to the intended destination(currently a file stream). The
 * file stream should be initialized by the client of this class
 */
class ColumnBuffer
{
 public:
  /** @brief default Constructor
   */
  ColumnBuffer(ColumnInfo* pColInfo, Log* logger);

  /** @brief default Destructor
   */
  virtual ~ColumnBuffer();

  /** @brief Final flushing of data and headers prior to closing the file.
   * This is a no-op for uncompressed columns.
   * @param bTruncFile is file to be truncated
   * @return NO_ERROR or success
   */
  virtual int finishFile(bool bTruncFile);

  /** @brief Returns size of the buffer
   */
  int getSize() const
  {
    return fBufSize;
  }

  /** @brief Reset the ColBuf to-be-compressed buffer prior to importing the
   *  next extent.  This is a no-op for uncompressed columns.
   * @param startFileOffset (output) File offset to start of active chunk
   */
  virtual int resetToBeCompressedColBuf(long long& startFileOffset);

  /** @brief Set the IDBDataFile* destination for the applicable col segment file.
   *
   * @param The destination IDBDataFile stream to which buffer data will be written
   * @param Starting HWM for cFile
   * @param Headers with ptr information (only applies to compressed files)
   */
  virtual int setDbFile(IDBDataFile* const cFile, HWM startHwm, const char* hdrs);

  /** @brief Resize the buffer, also copying the section denoted by the
   * offsets to the new buffer.  If offsets are -1, then the buffer is
   * expanded, but no copy is performed.
   *
   * @param newSize The new size of the buffer
   * @param startOffset The start offset in the current buffer from where the
   * previous data need to be copied
   * @param endOffset The end offset upto which the data should be copied to
   * new buffer
   */
  void resizeAndCopy(int newSize, int startOffset, int endOffset);

  /** @brief Write data to buffer
   *
   * @param data
   * @param startOffset
   * @param bytes
   */
  void write(const void* const data, int startOffset, int bytes) const;

  /** @brief Write data to FILE
   *
   * @param startOffset The buffer offset from where the write should begin
   * @param writeSize   The number of bytes to be written to the file
   * @param fillUpWEmpties The flag to fill the buffer with empty magic values
   *                      up to the block boundary.
   */
  virtual int writeToFile(int startOffset, int writeSize, bool fillUpWEmpties = false);

 protected:
  // Disable copy constructor and assignment operator by declaring and
  // not defining.
  ColumnBuffer(const ColumnBuffer&);
  ColumnBuffer& operator=(const ColumnBuffer&);

  unsigned char* fBuffer;  // Internal buffer
  int fBufSize;            // Size of the internal buffer
  IDBDataFile* fFile;      // The column file output stream
  ColumnInfo* fColInfo;    // parent ColumnInfo Object
  Log* fLog;               // Logger
  HWM fStartingHwm;        // Starting HWM for current column segment file
};

}  // namespace WriteEngine