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genie.rs 2.33 KiB
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  • use std::{
        collections::HashMap,
    
    João Magalhães's avatar
    João Magalhães committed
        fmt::{self, Display, Formatter},
    
    };
    
    #[derive(Clone)]
    pub struct GameGenie {
        /// Hash map that contains the complete set of Game Genie
        /// codes that have been registered for the current ROM.
        /// These codes are going to apply a series of patches to
        /// the ROM effectively allowing the user to cheat.
        codes: HashMap<u16, GameGenieCode>,
    }
    
    impl GameGenie {
        pub fn new() -> Self {
            Self {
                codes: HashMap::new(),
            }
        }
    
        pub fn contains_addr(&self, addr: u16) -> bool {
            self.codes.contains_key(&addr)
        }
    
        pub fn get_addr(&self, addr: u16) -> &GameGenieCode {
            self.codes.get(&addr).unwrap()
        }
    
        pub fn add_code(&mut self, code: &str) -> Result<&GameGenieCode, &str> {
            if code.len() != 11 {
                return Err("Invalid Game Genie code length");
            }
    
            let code_u = code.to_uppercase();
    
            let new_data_slice = &code_u[0..=1];
            let new_data = u8::from_str_radix(new_data_slice, 16).unwrap();
    
            let old_data_slice = format!("{}{}", &code_u[8..=8], &code_u[10..=10]);
            let old_data: u8 = u8::from_str_radix(old_data_slice.as_str(), 16)
                .unwrap()
                .rotate_right(2)
                ^ 0xba;
    
            let addr_slice = format!("{}{}{}", &code_u[6..=6], &code_u[2..=2], &code_u[4..=5]);
            let addr = u16::from_str_radix(addr_slice.as_str(), 16).unwrap() ^ 0xf000;
    
            let genie_code = GameGenieCode {
                code: code_u,
                addr,
                new_data,
                old_data,
            };
    
            self.codes.insert(addr, genie_code);
            Ok(self.codes.get(&addr).unwrap())
        }
    }
    
    impl Default for GameGenie {
        fn default() -> Self {
            Self::new()
        }
    }
    
    #[derive(Clone)]
    pub struct GameGenieCode {
        pub code: String,
        pub addr: u16,
        pub new_data: u8,
        pub old_data: u8,
    }
    
    impl GameGenieCode {
        pub fn short_description(&self) -> String {
            self.code.to_string()
        }
    
        pub fn description(&self) -> String {
            format!(
                "Code: {}, Address: 0x{:04x}, New Data: 0x{:04x}, Old Data: 0x{:04x}",
                self.code, self.addr, self.new_data, self.old_data
            )
        }
    }
    
    impl Display for GameGenieCode {
        fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
            write!(f, "{}", self.short_description())
        }
    }