Struct HighScoreManager 

pub struct HighScoreManager {
    db: Db,
}

Motivation for this DB

To use something else than SQL DB to change ;) Top-edge DB For a more rock solid DB in Rust use redb (more typed (no manuel BE management), more stable, less innovant)

Strengths

• Sled database guarantees that its iterators, including those returned by db.iter() and db.range(), will return elements in lexicographical order of their keys. (as raw byte slices)
• This is a fundamental feature of sled because it is built upon a $\text{Bw-Tree}$ structure, which is a type of ordered, persistent tree.
• The sorting is strictly lexicographical; you must ensure that multibyte numeric keys are stored in Big-Endian byte order.
• Big-Endian (BE): Stores the Most Significant Byte (MSB) first. This is required for correct lexicographical sorting of numbers.

To explore the DB content by hands:

• cargo install sledcli (or use EDMA)
• hex or str to change the view
• Pairs or keys

Why TOML serialisation

• Provide a better visualization by hands
• Not too much data, TOML overhead is unseen
• Already used for arguments serialisation, avoid a new dependency (and the bincode crate story is a lesson-teller)
• NB: on other projects with others constrains postcard,rkyv,or borsh

Fields

db: Db

Implementations

impl HighScoreManager

pub fn new() -> Result<Self, Error>

Errors

If DB reads / writes issues

pub fn new_with_custom_path<P: AsRef<Path>>(path: P) -> Result<Self, Error>

Errors

If DB reads / writes issues

pub fn save_score( &self, score: &HighScore, ) -> Result<Option<usize>, Box<dyn Error>>

Save the score in the DB and then shrink the DB to MAX_SCORE_ENTRIES if the score is not in the best MAX_SCORE_ENTRIES, it will not be inserted

Errors

If DB reads / writes issues

pub fn shrink_db(&self) -> Result<(), Box<dyn Error>>

Shrink the DB to MAX_SCORE_ENTRIES size

Errors

If DB reads / writes issues

pub fn get_top_scores(&self) -> Vec<HighScore>

pub fn get_rank( &self, player_score_value: u32, ) -> Result<Option<usize>, Box<dyn Error>>

Get the rank of the score submitted among the MAX_SCORE_ENTRIES Use the Sled lexicographic order to have it free

Errors

If DB reads / writes issues