/***************************************************************************
    copyright            : (C) 2011 by Lukas Lalinsky
    email                : lalinsky@gmail.com
 ***************************************************************************/

/***************************************************************************
 *   This library is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU Lesser General Public License version   *
 *   2.1 as published by the Free Software Foundation.                     *
 *                                                                         *
 *   This library 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     *
 *   Lesser General Public License for more details.                       *
 *                                                                         *
 *   You should have received a copy of the GNU Lesser General Public      *
 *   License along with this library; if not, write to the Free Software   *
 *   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA         *
 *   02110-1301  USA                                                       *
 *                                                                         *
 *   Alternatively, this file is available under the Mozilla Public        *
 *   License Version 1.1.  You may obtain a copy of the License at         *
 *   http://www.mozilla.org/MPL/                                           *
 ***************************************************************************/

#ifndef TAGLIB_IOSTREAM_H
#define TAGLIB_IOSTREAM_H

#include "taglib_export.h"
#include "taglib.h"
#include "tbytevector.h"

namespace TagLib {

#ifdef _WIN32
  class TAGLIB_EXPORT FileName
  {
  public:
    FileName(const wchar_t *name) : m_wname(name) {}
    FileName(const char *name) : m_name(name) {}
    operator const wchar_t *() const { return m_wname.c_str(); }
    operator const char *() const { return m_name.c_str(); }
  private:
    std::string m_name;
    std::wstring m_wname;
  };
#else
  typedef const char *FileName;
#endif

  //! An abstract class that provides operations on a sequence of bytes

  class TAGLIB_EXPORT IOStream
  {
  public:
    /*!
     * Position in the file used for seeking.
     */
    enum Position {
      //! Seek from the beginning of the file.
      Beginning,
      //! Seek from the current position in the file.
      Current,
      //! Seek from the end of the file.
      End
    };

    IOStream();

    /*!
     * Destroys this IOStream instance.
     */
    virtual ~IOStream();

    /*!
     * Returns the stream name in the local file system encoding.
     */
    virtual FileName name() const = 0;

    /*!
     * Reads a block of size \a length at the current get pointer.
     */
    virtual ByteVector readBlock(ulong length) = 0;

    /*!
     * Attempts to write the block \a data at the current get pointer.  If the
     * file is currently only opened read only -- i.e. readOnly() returns true --
     * this attempts to reopen the file in read/write mode.
     *
     * \note This should be used instead of using the streaming output operator
     * for a ByteVector.  And even this function is significantly slower than
     * doing output with a char[].
     */
    virtual void writeBlock(const ByteVector &data) = 0;

    /*!
     * Insert \a data at position \a start in the file overwriting \a replace
     * bytes of the original content.
     *
     * \note This method is slow since it requires rewriting all of the file
     * after the insertion point.
     */
    virtual void insert(const ByteVector &data, ulong start = 0, ulong replace = 0) = 0;

    /*!
     * Removes a block of the file starting a \a start and continuing for
     * \a length bytes.
     *
     * \note This method is slow since it involves rewriting all of the file
     * after the removed portion.
     */
    virtual void removeBlock(ulong start = 0, ulong length = 0) = 0;

    /*!
     * Returns true if the file is read only (or if the file can not be opened).
     */
    virtual bool readOnly() const = 0;

    /*!
     * Since the file can currently only be opened as an argument to the
     * constructor (sort-of by design), this returns if that open succeeded.
     */
    virtual bool isOpen() const = 0;

    /*!
     * Move the I/O pointer to \a offset in the stream from position \a p.  This
     * defaults to seeking from the beginning of the stream.
     *
     * \see Position
     */
    virtual void seek(long offset, Position p = Beginning) = 0;

    /*!
     * Reset the end-of-stream and error flags on the stream.
     */
    virtual void clear();

    /*!
     * Returns the current offset within the stream.
     */
    virtual long tell() const = 0;

    /*!
     * Returns the length of the stream.
     */
    virtual long length() = 0;

    /*!
     * Truncates the stream to a \a length.
     */
    virtual void truncate(long length) = 0;

  private:
    IOStream(const IOStream &);
    IOStream &operator=(const IOStream &);
  };

}

#endif
