GY-63_MS5611/libraries/DEVNULL

DEVNULL

Arduino library for a /dev/null stream.

Description

The library implements a stream class that mimics the /dev/null device of a Linux system. You can write everything to it. You can never read data from it as it always returns EOF (end of file);

The 0.1.0 version is a minimal implementation that can be optimized. it implements the write(const uint8_t data) call and e.g. a float is still converted to individual characters that are send one after another. Strings and text send every byte.

The advantage is that printing takes time and e.g. one can use it to measure the print class performance.

Performance can be increased by implementing all methods of the print interface with only a return 0; (or at least print(Type) as the println(T) would only call once extra for the "\n".

Versions

0.1.2

• sets the timeout for reading to 0. No need to wait longer with DEVNULL. this improves the find(...) calls substantially.
• added size_t write( const uint8_t *buffer, size_t size) for faster string processing.

0.1.4

• add lastByte() to check last byte written.
• split of .cpp

Interface

• DEVNULL() constructor, sets the timeout to zero.
• int available() always return zero.
• int peek() always returns EOF.
• int read() always return EOF.
• void flush() does nothing but keeps some compilers happy.
• size_t write(const uint8_t data) implements print interface. returns 1.
• size_t write( const uint8_t *buffer, size_t size) implements print interface. Returns size.
• int lastByte() returns last byte written (debug and test purpose). Returns -1 if no byte has been written yet.

Operation

Use with care.

See examples.

Future

Could

• add byte counter (uint32_t)
• investigate if DEVNULL can be used to harvest entropy?
  • sum xor of all data + timestamp?
  • enable / disable flag (complex)
  • => /dev/entropy class?
• flush() could reset bottomLessPit to -1?

Wont

• add delay to mimic pause / tune behaviour for simulating devices
  • microseconds
  • delay per byte, esp long arrays might need other performance
  • out of scope for /dev/null => separate class?
• implement Print class to increase performance?
  • derived class?