Crate lcd_rus 

lcd-rus

lcd-rus is a crate for converting ASCII + Russian UTF-8 strings to the encoding commonly used by LCDs such as HD44780U. It’s a no_std crate designed to be used in an embedded environment. Both compile time and run time transformations are available.

Please note that this library does not include routines for actually communicating with the display. You need a separate crate for that.

Compile time transformation

Two macros, lcd_const and lcd_literal, are provided to allow transcoding strings at compile time. This is usually preferred as it avoids inflating the binary, incurs zero runtime overhead, and ensures characters are valid during the build.

You must use the crate itself in places where the macros are invoked.

Run time transformation

If there’s no way around runtime transformation lcd_encode_runtime can be used to perform it. It’s generally discouraged due not being very optimized neither for size nor speed, including calling safe versions of operations where possible.

On Arduino Uno the code for performing transformations at runtime takes about 3 KB of flash while using compile time transformation takes exactly zero.

Other

const function lcd_length is provided for counting characters. It’s usually not needed unless you’re doing runtime transformation or writing your own macros.

Panics

Functions may panic if provided with invalid UTF-8; this should not be surprising as strings in Rust are expected to be UTF-8 encoded. Additionally, compile-time transformation will panic to cause build failure if a character can’t be transcoded.

Caveats

Some LCD libraries take &str instead of &[u8] for strings; this is somewhat of a bug since LCD screens don’t expect UTF-8 encoded text. You should report this as an issue to library maintainers and work around it manually for the time being.

Macros

lcd_const

Convert a string literal into LCD encoding, storing result in a constant.

lcd_literal

Convert a string literal into LCD encoding, returning the result.

Functions

lcd_encode_runtime

Convert a string into LCD encoding at runtime.

lcd_length

Get length of an array required to fit the LCD encoded characters.