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|
use header::{Header, Kind};
use std::fs::File;
use std::io::{ErrorKind, Read};
/// Version for this program.
const VERSION: &str = "0.1.0";
#[derive(Default)]
struct Args {
file: String,
header: bool,
}
fn print_help() {
println!("Display information about NES/Famicom ROM files.\n");
println!("usage: readrom [OPTIONS] <FILE>\n");
println!("Options:");
println!(" -h, --help\t\tPrint this message.");
println!(" -H, --header\t\tJust print the ROM header and quit.");
println!(" -v, --version\t\tPrint the version of this program.");
std::process::exit(0);
}
// Parse the arguments given to the program and returns an Args object with the
// given information.
fn parse_arguments() -> Args {
let mut args = std::env::args();
let mut res = Args::default();
// Skip command name.
args.next();
for arg in args {
match arg.as_str() {
"-h" | "--help" => print_help(),
"-H" | "--header" => {
if res.header {
die("do not specify the '-H/--header' flag twice".to_string());
}
res.header = true;
}
"-v" | "--version" => {
println!("readrom {VERSION}");
std::process::exit(0);
}
_ => {
if arg.starts_with('-') {
die(format!("don't know how to handle the '{arg}' flag"));
}
if !res.file.is_empty() {
die("cannot have multiple source files".to_string());
}
res.file = arg;
}
}
}
if res.file.is_empty() {
die("you need to specify the file to be read".to_string());
}
res
}
// Capitalize the given string.
fn capitalize(s: &str) -> String {
let mut c = s.chars();
match c.next() {
None => String::new(),
Some(f) => f.to_uppercase().collect::<String>() + c.as_str(),
}
}
fn print_header(header: &Header) {
println!("Header:");
match header.kind {
Kind::INes => println!(" Kind:\t\t\tiNES"),
Kind::Nes20 => println!(" Kind:\t\t\tNES 2.0"),
}
println!(
" PRG ROM size:\t\t{} bytes ({}KB)",
header.prg_rom_size * 16 * 1024,
header.prg_rom_size * 16
);
println!(
" CHR ROM size:\t\t{} bytes ({}KB)",
header.chr_rom_size * 8 * 1024,
header.chr_rom_size * 8
);
if let Some(def) = &header.prg_ram_definition {
println!(
" PRG-RAM size:\t\t{} bytes ({}KB); {}",
def.size,
def.size / 1024,
def.kind
);
}
if let Some(def) = &header.chr_ram_definition {
println!(
" CHR-RAM size:\t\t{} bytes ({}KB); {}",
def.size,
def.size / 1024,
def.kind
);
}
println!(" Mapper:\t\t{}", header.mapper);
println!(
" Mirroring:\t\t{}",
capitalize(header.nametable_arrangement.mirroring())
);
println!(" CPU/PPU timing:\t{}", header.timing);
}
fn print_vectors(addrs: &[u8]) {
println!("Vectors:");
println!(
" NMI:\t\t\t{:#04x}",
u16::from_le_bytes([addrs[0], addrs[1]])
);
println!(
" Reset:\t\t{:#04x}",
u16::from_le_bytes([addrs[2], addrs[3]])
);
println!(
" IRQ:\t\t\t{:#04x}",
u16::from_le_bytes([addrs[4], addrs[5]])
);
}
// Print the given `message` and exit(1).
fn die(message: String) {
println!("error: {message}");
std::process::exit(1);
}
fn main() {
let args = parse_arguments();
let Ok(mut input) = File::open(&args.file) else {
die(format!("failed to open the given file '{}'", args.file));
return;
};
// Header.
let mut buf = vec![0u8; 0x10];
if let Err(e) = input.read_exact(&mut buf) {
match e.kind() {
ErrorKind::UnexpectedEof => die("malformed ROM file".to_string()),
_ => die(e.to_string()),
}
}
let header = match Header::try_from(buf.as_slice()) {
Ok(h) => h,
Err(e) => {
die(e.to_string());
return;
}
};
print_header(&header);
if args.header {
std::process::exit(0);
}
// PRG ROM.
buf = vec![0u8; header.prg_rom_size * 16 * 1024];
if let Err(e) = input.read_exact(&mut buf) {
match e.kind() {
ErrorKind::UnexpectedEof => die("could not read advertised PRG ROM space".to_string()),
_ => die(e.to_string()),
}
}
// Vectors.
let vectors = &buf.as_slice()[buf.len() - 6..];
print_vectors(vectors);
}
|
