/*
 *
 *  Copyright (C) 1994-2024, OFFIS e.V.
 *  All rights reserved.  See COPYRIGHT file for details.
 *
 *  This software and supporting documentation were developed by
 *
 *    OFFIS e.V.
 *    R&D Division Health
 *    Escherweg 2
 *    D-26121 Oldenburg, Germany
 *
 *
 *  Module:  dcmdata
 *
 *  Author:  Marco Eichelberg
 *
 *  Purpose: DcmOutputFileStream and related classes,
 *    implements streamed output to files.
 *
 */

#ifndef DCOSTRMF_H
#define DCOSTRMF_H

#include "dcmtk/config/osconfig.h"
#include "dcmtk/dcmdata/dcostrma.h"

class OFFile;

/** consumer class that stores data in a plain file.
 */
class DCMTK_DCMDATA_EXPORT DcmFileConsumer: public DcmConsumer
{
public:
  /** constructor
   *  @param filename name of file to be created (may contain wide chars
   *    if support enabled)
   */
  DcmFileConsumer(const OFFilename &filename);

  /** constructor
   *  @param file structure, file must already be open for writing
   */
  DcmFileConsumer(FILE *file);

  /** constructor
   *  @param OFFile instance, file must already be open for writing,
   *   and the OFFile object must remain valid as long as this instance
   *   exists.
   */
  DcmFileConsumer(OFFile& file);

  /// destructor
  virtual ~DcmFileConsumer();

  /** returns the status of the consumer. Unless the status is good,
   *  the consumer will not permit any operation.
   *  @return status, true if good
   */
  virtual OFBool good() const;

  /** returns the status of the consumer as an OFCondition object.
   *  Unless the status is good, the consumer will not permit any operation.
   *  @return status, EC_Normal if good
   */
  virtual OFCondition status() const;

  /** returns true if the consumer is flushed, i.e. has no more data
   *  pending in it's internal state that needs to be flushed before
   *  the stream is closed.
   *  @return true if consumer is flushed, false otherwise
   */
  virtual OFBool isFlushed() const;

  /** returns the minimum number of bytes that can be written with the
   *  next call to write(). The DcmObject write methods rely on avail
   *  to return a value > 0 if there is no I/O suspension since certain
   *  data such as tag and length are only written "en bloc", i.e. all
   *  or nothing.
   *  @return minimum of space available in consumer
   */
  virtual offile_off_t avail() const;

  /** processes as many bytes as possible from the given input block.
   *  @param buf pointer to memory block, must not be NULL
   *  @param buflen length of memory block
   *  @return number of bytes actually processed.
   */
  virtual offile_off_t write(const void *buf, offile_off_t buflen);

  /** instructs the consumer to flush its internal content until
   *  either the consumer becomes "flushed" or I/O suspension occurs.
   *  After a call to flush(), a call to write() will produce undefined
   *  behaviour.
   */
  virtual void flush();

  /** closes the file associated with this object.
   *  Updates the internal status variable in case of an error.
   */
  virtual void fclose();

private:

  /// private unimplemented copy constructor
  DcmFileConsumer(const DcmFileConsumer&);

  /// private unimplemented copy assignment operator
  DcmFileConsumer& operator=(const DcmFileConsumer&);

  /// container encapsulating a FILE *
  OFFile file_container_;

  /// reference the file we actually writing to.
  /// Points to file_container_ in most, but not all cases
  OFFile& file_;

  /// status
  OFCondition status_;
};


/** output stream that writes into a plain file
 */
class DCMTK_DCMDATA_EXPORT DcmOutputFileStream: public DcmOutputStream
{
public:
  /** constructor
   *  @param filename name of file to be created (may contain wide chars
   *    if support enabled)
   */
  DcmOutputFileStream(const OFFilename &filename);

  /** constructor
   *  @param file structure, file must already be open for writing
   */
  DcmOutputFileStream(FILE *file);

  /** constructor
   *  @param OFFile instance, file must already be open for writing,
   *   and the OFFile object must remain valid as long as this instance
   *   exists.
   */
  DcmOutputFileStream(OFFile& file);

  /// destructor
  virtual ~DcmOutputFileStream();

  /** close file
   *  @return EC_Normal if successful, an error code otherwise
   */
  virtual OFCondition fclose();

private:

  /// private unimplemented copy constructor
  DcmOutputFileStream(const DcmOutputFileStream&);

  /// private unimplemented copy assignment operator
  DcmOutputFileStream& operator=(const DcmOutputFileStream&);

  /// the final consumer of the filter chain
  DcmFileConsumer consumer_;
};

#endif
