vmap/include/itextstream.h
2020-11-17 12:16:16 +01:00

107 lines
3.5 KiB
C++

/*
Copyright (C) 2001-2006, William Joseph.
All Rights Reserved.
This file is part of GtkRadiant.
GtkRadiant 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; either version 2 of the License, or
(at your option) any later version.
GtkRadiant 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 GtkRadiant; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#if !defined( INCLUDED_ITEXTSTREAM_H )
#define INCLUDED_ITEXTSTREAM_H
/// \file
/// \brief Text-stream interfaces.
#include <cstddef>
#include "generic/static.h"
/// \brief A read-only character-stream.
class TextInputStream
{
public:
/// \brief Attempts to read the next \p length characters from the stream to \p buffer.
/// Returns the number of characters actually stored in \p buffer.
virtual std::size_t read( char* buffer, std::size_t length ) = 0;
};
/// \brief A write-only character-stream.
class TextOutputStream
{
public:
/// \brief Attempts to write \p length characters to the stream from \p buffer.
/// Returns the number of characters actually read from \p buffer.
virtual std::size_t write( const char* buffer, std::size_t length ) = 0;
};
/// \brief Calls the overloaded function ostream_write() to perform text formatting specific to the type being written.
/*! Note that ostream_write() is not globally defined - it must be defined once for each type supported.\n
To support writing a custom type MyClass to any kind of text-output-stream with operator<<:
\code
template<typename TextOutputStreamType>
TextOutputStreamType& ostream_write(TextOutputStreamType& ostream, const MyClass& myClass)
{
return ostream << myClass.getName() << ' ' << myClass.getText();
}
\endcode
Expressing this as a template allows it to be used directly with any concrete text-output-stream type, not just the abstract TextOutputStream\n
\n
This overload writes a single character to any text-output-stream - ostream_write(TextOutputStreamType& ostream, char c).
*/
template<typename T>
inline TextOutputStream& operator<<( TextOutputStream& ostream, const T& t ){
return ostream_write( ostream, t );
}
class NullOutputStream : public TextOutputStream
{
public:
std::size_t write( const char*, std::size_t length ){
return length;
}
};
class OutputStreamHolder
{
NullOutputStream m_nullOutputStream;
TextOutputStream* m_outputStream;
public:
OutputStreamHolder()
: m_outputStream( &m_nullOutputStream ){
}
void setOutputStream( TextOutputStream& outputStream ){
m_outputStream = &outputStream;
}
TextOutputStream& getOutputStream(){
return *m_outputStream;
}
};
typedef Static<OutputStreamHolder> GlobalOutputStream;
/// \brief Returns the global output stream. Used to display messages to the user.
inline TextOutputStream& globalOutputStream(){
return GlobalOutputStream::instance().getOutputStream();
}
class ErrorStreamHolder : public OutputStreamHolder {};
typedef Static<ErrorStreamHolder> GlobalErrorStream;
/// \brief Returns the global error stream. Used to display error messages to the user.
inline TextOutputStream& globalErrorStream(){
return GlobalErrorStream::instance().getOutputStream();
}
#endif