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/*
* Copyright (C) 2007-2019 Xagasoft, All rights reserved.
*
* This file is part of the libbu++ library and is released under the
* terms of the license contained in the file LICENSE.
*/
#ifndef BU_STREAM_H
#define BU_STREAM_H
#include "bu/config.h"
#include <stdint.h>
#include <stdio.h>
#include "bu/string.h"
namespace Bu
{
/**
* The basis for a completely general data transport mechanism. Anything
* that inherits from this should provide at least the basic read and/or
* write functions, and very probably the close function. Any functions
* that aren't supported should throw an exception if called.
*
* The constructor of a child class should pretty much universally be used
* to open the stream. I can't think of anything that should require an
* exception.
*@ingroup Streams
*/
class Stream
{
public:
Stream();
virtual ~Stream();
/**
* Close the stream.
*/
virtual void close() = 0;
/**
* Read data from the stream into a buffer.
*@param pBuf (void *) Buffer which will be filled.
*@param nBytes (size_t) Max data to read.
*@returns (size_t) Amount of data read.
*/
virtual size read( void *pBuf, size iBytes ) = 0;
/**
* Attempts to read a complete line from the stream. This will stop
* reading when it has reached the end of the stream, or runs out of
* data in a non-blocking stream.
*@returns The line read, not including newline character.
*/
virtual Bu::String readLine();
/**
* Reads all data from the current position onward until isEos returns
* true and returns it as a Bu::String. This will also return if no
* data is available and the stream is in non-blocking mode. This
* function is intended for very particular circumstances and is often
* not the most efficient way to access the data that you would like.
*@returns The entire stream contents.
*/
virtual Bu::String readAll();
/**
* Write data to the stream.
*@param pBuf (const void *) The data to be written.
*@param nBytes (size_t) Amount of data to write from pBuf.
*@returns (size_t) Amount of data actually written.
*/
virtual size write( const void *pBuf, size iBytes ) = 0;
virtual size write( const Bu::String &sBuf );
/**
* Get the current position in the stream.
*@returns (long) The current position in the stream.
*/
virtual size tell() = 0;
/**
* Seek to a position in the stream relative to the current position.
*@param offset (long) Offset from current position to seek to.
*/
virtual void seek( size offset ) = 0;
/**
* Set position in the stream relative to the start of the stream.
*@param pos (long) The position.
*/
virtual void setPos( size pos ) = 0;
/**
* Set position in the stream relative to the end of the stream.
*@param pos (long) The position.
*/
virtual void setPosEnd( size pos ) = 0;
/**
* Are we at the end of the stream?
*@returns (bool) Are we at the end of the stream?
*/
virtual bool isEos() = 0;
/**
* Is the stream open?
*@returns (bool) Is the stream open?
*/
virtual bool isOpen() = 0;
/**
* Flush any data still held in buffers.
*/
virtual void flush() = 0;
/**
* In non-blocking streams this indicates if a read operation will
* return data at the moment or not. In blocking streams this should
* return the same value as isEos().
*/
virtual bool canRead() = 0;
/**
* In non-blocking streams this indicates if a write operation will
* actually write one or more bytes. In some cases writing is not
* allowed (e.g. internal buffers are full) temporarilly. In blocking
* streams this should return the same value as isWritable.
*/
virtual bool canWrite() = 0;
/**
* Indicates if the stream is capable of read operations. This does not
* indicate if such operations will return useful data, see canRead for
* that.
*/
virtual bool isReadable() = 0;
/**
* Indicates if the stream is capable of write operations. This does
* not indicate if such operations will succeed or fail, see canWrite
* for that.
*/
virtual bool isWritable() = 0;
/**
* Indicates if the stream is capable of seek operations. This is
* generally false for non-blocking streams. Some buffered streams may
* support limited in-buffer seeking.
*/
virtual bool isSeekable() = 0;
/**
* Are we currently set to block mode?
*@returns (bool)
*/
virtual bool isBlocking() = 0;
/**
* Set stream to blocking or non-blocking mode.
*@param bBlocking (bool) Whether we should block or not.
*/
virtual void setBlocking( bool bBlocking=true ) = 0;
/**
* Set the size of the stream, this does not apply to many types of
* streams. For those that it does apply to, data will be added or
* removed from the end of the stream, but the content of the added
* data is undefined.
*/
virtual void setSize( size iSize ) = 0;
/**
* Returns the size of the stream if the stream can have a size. For
* streams that do not (sockets, pipes, etc.) this should throw an
* unsupported exception.
*/
virtual size getSize() const = 0;
/**
* Returns the block-size of the stream, if it has one. This should
* throw an unsupported exception. In some cases the block size
* returned will not represent quite the same thing, for example,
* sockets will return their MTU, while files will return the
* filesystem's block size, and memory buffers will throw an exception.
*/
virtual size getBlockSize() const = 0;
/**
* If possible, this returns a string that can be used to describe how
* to access the open stream. Not all streams support this, such as
* MemBuf, but for files it may give you a path to a file, for a socket
* it may give you an ip address, etc. If it isn't supported, an empty
* string may be returned.
*/
virtual Bu::String getLocation() const = 0;
private:
};
}
#endif
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