Aufgabe 7: Anwendung

Attributes can be used to influence the display of the output.

Note

The attributes might not be supported or have a different effect depending on the terminal emulator!

Color codes.

Default VT100 supports eight colors for both foreground and background (later versions 256 [8 bit] and even true color [32 bit]). The actual color is affected by the attributes and can look significantly different depending on the terminal emulator.

Constructor for the VT100-compatible console.

Sets up the serial connection as well

Method to output the buffer contents of the base class Stringbuffer.

The method is automatically called when the buffer is full, but can also be called explicitly to force output of the current buffer.

Implements OutputStream.

Change foreground color (for subsequent output)

Parameters

c

Color

Change background color (for subsequent output)

Parameters

c

Color

Change text attribute (for subsequent output)

Parameters

a

Attribute

Reset terminal.

Clear screen, place cursor at the beginning and reset colors and attributes to the default value.

Set the cursor position.

Parameters

x	Column in window
y	Row in window

Read the current cursor position.

It is possible to receive the current cursor position via a special escape code: Request by sending \e[6n, answer will be \e[y;xR with y (row) and x (column) as human readable ASCII character number.

However, depending on the implementation, it may be possible that the system waits endlessly due to an disconnected terminal or data transmission error.

Parameters

x	Column in window
y	Row in window

Returns

true if position was successfully received

Display multiple characters in the window starting at the current cursor position.

This method can be used to output a string, starting at the current cursor position. Since the string does not need to contain a '\0' termination (as it is usually the case in C), the parameter length is required to specify the number of characters in the string.

The text is displayed using the previously configured attributes, fore- and background color.

A line break will occur wherever the character \n is inserted in the text to be output (for compatibility reasons a \r is automatically appended).

Parameters

str	String to output
length	length of string

Initialize the interrupt driven serial connection.

Only receive interrupts are supported, however, send interrupts could be implemented accordingly: interrupt if line is free/ready.

Prologue for serial receive interrupts.

The received character is placed in a local buffer (e.g. BBuffer) and – on success – an epilogue is requested.

Returns

true if the epilogue has to be executed.

Implements Gate.

Epilogue for serial receive interrupts.

The receival of a character is signaled to a possibly waiting thread. For this purpose, a semaphore is used whose counter indicates how many characters are available in the buffer.

Reimplemented from Gate.

Application interface to retrieve characters from the serial connection.

This method returns the last received character. If no character has been received, the calling application thread is blocked until a character is available – this is achieved by using a Semaphore.

Returns

Received character