// ======================================================================== //
//  I/O Interface
//
//  Abstract base class for a generic byte-oriented I/O interface as 
//  expected by the rest of the code.  This naive interface ignores errors
//  for now; we can always extend it later if/when it becomes necessary.
//
//  The 'send' method must ensure that the data gets sent; it need not wait 
//  for the data to send as long as it's queued.  
//
//  The 'recv' method will return as much data as is currently available, 
//  but should not block.
//
//  The 'pump' method should send any data that's queued to send, and 
//  drain any incoming data to a private queue for a future call to 'recv'.
//  The pump method should not block, however.  It should just do a best
//  effort "send what I can send; receive what I can receive" without 
//  blocking.
//
//  The 'flush' method is like 'pump', except it blocks on send.  It will
//  try to send data until all queued data goes, or until it fails to 
//  advance for "a time."  (Undefined; recommend timing out at a couple
//  seconds without advancing.)  
//
// ======================================================================== //

#ifndef IO_IF_HPP_
#define IO_IF_HPP_

#include <stdint.h>
#include <vector>

class io_if
{
    public:
        typedef enum { FLUSH_FAILED, FLUSH_OK } flush_status;

        virtual ~io_if() { };

        virtual void send( uint8_t b ) = 0;
        virtual void send( std::vector< uint8_t >& ) = 0;
        virtual int  recv( uint8_t &b ) = 0;
        virtual int  recv( std::vector< uint8_t >& ) = 0;
        virtual void pump( void ) = 0;
        virtual flush_status flush( void ) = 0;
        virtual int  remaining_to_send() = 0;
};

#endif