Struct RomFile 

pub struct RomFile {

    pub name: Option<String>,
    pub prg_memory: PrgMemory,
    pub chr_memory: ChrMemory,
    pub mapper: RomMapper,
    pub default_expansion_device: ExpansionDevice,
    pub misc_rom_count: u8,
    pub extended_console_type: Option<ExtendedConsoleType>,
    pub vs_system_hardware_type: Option<VsHardwareType>,
    pub vs_system_ppu_type: Option<VsSystemPpuType>,
    pub timing_region: RomTimingRegion,
    pub console_type: ConsoleType,
    pub hardwired_nametable_layout: bool,
    pub is_battery_backed: bool,
    pub trainer_present: bool,
    pub alternative_nametables: bool,
    pub submapper_number: u8,
    pub data_checksum: [u8; 32],
    pub data: Vec<u8>,
}

A parsed NES ROM file.

Contains all metadata extracted from the ROM header (mapper number, memory sizes, mirroring, etc.) as well as the raw ROM data used for loading into the emulator’s memory map.

Loading a ROM

use monsoon_core::emulation::rom::RomFile;

let rom = RomFile::load(raw_bytes, Some("my_game.nes".to_string())).expect("invalid ROM");
println!("Mapper: {}", rom.mapper);

Constructing a ROM programmatically

Use RomBuilder for test scenarios where you need custom ROM metadata without providing actual ROM data.

Fields

name: Option<String>

Human-readable name of the ROM (typically the file name).

prg_memory: PrgMemory

PRG (program) memory sizes.

chr_memory: ChrMemory

CHR (character/graphics) memory sizes.

mapper: RomMapper

iNES mapper number identifying the cartridge board hardware.

default_expansion_device: ExpansionDevice

Default expansion device identifier (NES 2.0).

misc_rom_count: u8

Number of miscellaneous ROM areas (NES 2.0).

extended_console_type: Option<ExtendedConsoleType>

Extended console type (NES 2.0), if applicable.

vs_system_hardware_type: Option<VsHardwareType>

VS System hardware type, if applicable.

vs_system_ppu_type: Option<VsSystemPpuType>

VS System PPU type, if applicable.

timing_region: RomTimingRegion

CPU/PPU timing mode (0 = NTSC, 1 = PAL, 2 = Multi-region, 3 = Dendy).

console_type: ConsoleType

Console type (0 = NES/Famicom, 1 = VS System, 2 = Playchoice-10, 3 = Extended).

hardwired_nametable_layout: bool

Nametable mirroring mode from header bit 0 (true = vertical, false = horizontal).

is_battery_backed: bool

Whether the cartridge contains battery-backed persistent memory.

trainer_present: bool

Whether a 512-byte trainer is present before PRG data.

alternative_nametables: bool

Whether the ROM uses alternative nametable layouts.

submapper_number: u8

Submapper number (NES 2.0).

data_checksum: [u8; 32]

SHA-256 checksum of the raw ROM data.

data: Vec<u8>

Raw ROM file bytes. Skipped during serialization to reduce save state size.

Implementations

impl RomFile

pub fn load(data: &[u8], name: Option<String>) -> Result<RomFile, ParseError>

Parses a ROM file from raw bytes.

Auto-detects the ROM format (iNES, NES 2.0, archaic iNES, etc.) from the header and extracts all metadata. The raw data is stored in data and a SHA-256 checksum is computed.

Arguments

• data — The complete ROM file as a byte slice.
• name — An optional human-readable name (e.g., the file name).

Errors

Returns a ParseError if:

• The data is too short to contain a valid header (ParseError::InvalidHeader).
• The ROM format is not recognized (ParseError::UnsupportedFormat).
• The header declares sizes larger than the file (ParseError::SizeBiggerThanFile).

Trait Implementations

impl Clone for RomFile

fn clone(&self) -> RomFile

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for RomFile

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for RomFile

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl From<&[u8]> for RomFile

fn from(data: &[u8]) -> Self

Converts to this type from the input type.

impl From<&(&[u8], String)> for RomFile

fn from((data, name): &(&[u8], String)) -> Self

Converts to this type from the input type.

impl From<&RomFile> for RomFile

fn from(rom: &RomFile) -> Self

Converts to this type from the input type.

impl From<&String> for RomFile

Available on non-WebAssembly only.

fn from(path: &String) -> Self

Converts to this type from the input type.

impl Hash for RomFile

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for RomFile

fn eq(&self, other: &RomFile) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Serialize for RomFile

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl Eq for RomFile

impl StructuralPartialEq for RomFile