Stream.h++

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/* ---------------------------------------------------------------------------
   commonc++ - A C++ Common Class Library
   Copyright (C) 2005-2014  Mark A Lindner

   This file is part of commonc++.

   This library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public
   License as published by the Free Software Foundation; either
   version 2 of the License, or (at your option) any later version.

   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
   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public
   License along with this library; if not, write to the Free
   Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
   ---------------------------------------------------------------------------
*/

#ifndef __ccxx_Stream_hxx
#define __ccxx_Stream_hxx

#include <commonc++/Common.h++>
#include <commonc++/Buffer.h++>
#include <commonc++/IOException.h++>
#include <commonc++/MemoryBlock.h++>

namespace ccxx {

class AsyncIOTask; // fwd decl

enum IOMode {
  IORead,
  IOWrite,
  IOReadWrite
};

enum SeekMode {
  SeekAbsolute,
  SeekRelative,
  SeekEnd
};

class COMMONCPP_API Stream
{
  friend class Process;

 public:

  static const uint_t MAX_IOBLOCK_COUNT;

 protected:

  Stream();

  Stream(FileHandle handle, bool seekable = true, bool readable = true,
         bool writable = true);

 public:

  virtual ~Stream();

  virtual size_t read(ByteBuffer& buffer);

  virtual size_t read(CharBuffer& buffer);

  template<typename T> size_t read(Buffer<T>& buffer, size_t& partial)
  {
    size_t n = _readElem(reinterpret_cast<byte_t *>(buffer.getPointer()),
                         sizeof(T), buffer.getRemaining(), partial);

    if(n > 0)
      buffer.bump(n);

    return(n);
  }

  virtual size_t read(byte_t* buffer, size_t buflen);

  size_t read(byte_t* buffer, size_t buflen, int64_t offset,
              AsyncIOTask& task);

  size_t read(ByteBuffer& buffer, int64_t offset, AsyncIOTask& task);

  size_t write(const byte_t* buffer, size_t buflen, int64_t offset,
               AsyncIOTask& task);

  size_t write(ByteBuffer& buffer, int64_t offset, AsyncIOTask& task);

  virtual size_t readFully(ByteBuffer& buffer, size_t count = 0);

  virtual size_t readFully(CharBuffer& buffer, size_t count = 0);

  template<typename T> size_t readFully(Buffer<T>& buffer, size_t& partial)
  {
    size_t n = _readElemFully(reinterpret_cast<byte_t *>(buffer.getPointer()),
                              sizeof(T), buffer.getRemaining(), partial);

    if(n > 0)
      buffer.bump(n);

    return(n);
  }

  virtual size_t readFully(byte_t* buffer, size_t buflen);

  virtual size_t read(MemoryBlock* vec, uint_t count);

  virtual size_t write(ByteBuffer& buffer);

  virtual size_t write(CharBuffer& buffer);

  template<typename T> size_t write(Buffer<T>& buffer, size_t& partial)
  {
    size_t n = _writeElem(
      reinterpret_cast<const byte_t *>(buffer.getPointer()),
      sizeof(T), buffer.getRemaining(), partial);

    if(n > 0)
      buffer.bump(n);

    return(n);
  }

  virtual size_t write(const byte_t* buffer, size_t buflen);

  virtual size_t writeFully(ByteBuffer& buffer);

  virtual size_t writeFully(CharBuffer& buffer);

  template<typename T> size_t writeFully(Buffer<T>& buffer, size_t& partial)
  {
    size_t n = _writeElemFully(
      reinterpret_cast<const byte_t *>(buffer.getPointer()),
      sizeof(T), buffer.getRemaining(), partial);

    if(n > 0)
      buffer.bump(n);

    return(n);
  }

  virtual size_t writeFully(const byte_t* buffer, size_t buflen);

  virtual size_t write(const MemoryBlock* vec, uint_t count);

  virtual int64_t seek(int64_t offset, SeekMode mode = SeekAbsolute);

  virtual int64_t tell();

  inline bool isOpen() const
  { return(_canRead || _canWrite); }

  inline bool isSeekable() const
  { return(_seekable); }

  inline bool isReadable() const
  { return(_canRead); }

  inline bool isWritable() const
  { return(_canWrite); }

  inline bool isFullDuplex() const
  { return(_canRead && _canWrite); }

  inline bool isHalfDuplex() const
  { return(! _canRead || ! _canWrite); }

  virtual void close(IOMode mode = IOReadWrite);

  virtual void setTimeout(timespan_ms_t timeout);

  inline timespan_ms_t getTimeout() const
  { return(_timeout); }

 protected:

  void _init(FileHandle handle, bool seekable, bool readable, bool writable);

  FileHandle _handle;
  bool _seekable;
  bool _canRead;
  bool _canWrite;
  timespan_ms_t _timeout;
 private:

  size_t _readAsync(byte_t* buffer, size_t buflen, int64_t offset,
                    AsyncIOTask& task);
  size_t _writeAsync(const byte_t* buffer, size_t buflen, int64_t offset,
                     AsyncIOTask& task);

  size_t _readElem(byte_t* buffer, size_t size, size_t nelem, size_t& partial);
  size_t _readElemFully(byte_t* buffer, size_t size, size_t nelem,
                        size_t& partial);

  size_t _writeElem(const byte_t* buffer, size_t size, size_t nelem,
                    size_t& partial);
  size_t _writeElemFully(const byte_t* buffer, size_t size, size_t nelem,
                         size_t& partial);

  CCXX_COPY_DECLS(Stream);
};

} // namespace ccxx

#endif // __ccxx_Stream_hxx