gistfile1.rs

fn hex_to_bytes(hex: &str) -> ~[u8] {                                           
        let n = hex.len();                                                      
        assert!(n % 2 == 0);                                                    
        return vec::from_fn(n / 2, |i| {                                        
                u8::from_str_radix(hex.substr(i*2, 2), 16).expect("bad hex")    
        });                                                                     
}                                                                               

fn bytes_to_hex(bytes: &[u8]) -> ~str {                                         
        let hex_chars = ~"0123456789abcdef";                                    
        let n = bytes.len();                                                    
        let mut hex = str::with_capacity(n * 2);                                
        do bytes.each |byte| {                                                  
                hex.push_char(hex_chars[*byte >> 4] as char);                   
                hex.push_char(hex_chars[*byte & 0xf] as char);                  
                true                                                            
        };                                                                      
        return hex;                                                             
}