import sys

class StandardIOBuffer:
    """
    IOBuffer implementation that uses system standard input/output.
    
    This class provides direct access to stdin/stdout for IO operations.
    It implements a basic line-based input buffer to handle cases where
    multiple reads are needed to process all available input.
    """
    
    def __init__(self):
        """Initialize the standard IO buffer."""
        self._input_buffer: str = ""

    def read(self) -> str:
        """
        Read available input from stdin.
        
        If there is buffered input from a previous read, return that first.
        Otherwise, try to read new input from stdin if available.
        
        Returns:
            str: Content read from stdin, or empty string if no input available
        """
        # Return and clear any existing buffered input
        if self._input_buffer:
            content = self._input_buffer
            self._input_buffer = ""
            return content
            
        # Check if there's input available
        if not sys.stdin.isatty() and sys.stdin.readable():
            try:
                content = sys.stdin.read()
                if content:
                    return content
            except Exception:
                pass  # Ignore any read errors
                
        return ""
        
    def write(self, content: str) -> None:
        """
        Write content to stdout.
        
        Args:
            content: String content to write
        """
        if not content:
            return
            
        try:
            sys.stdout.write(content)
            sys.stdout.flush()
        except Exception:
            pass  # Ignore write errors
            
    def buffer_length(self) -> int:
        """
        Get the current length of buffered input.
        
        Returns:
            int: Number of characters in the input buffer
        """
        return len(self._input_buffer)