Enum PpuSnapshotError 

#[non_exhaustive]
pub enum PpuSnapshotError {
    Truncated(usize),
    TrailingBytes {
        consumed: usize,
        extra: usize,
    },
    UnsupportedVersion(u8),
    InvalidRegion(u8),
    InvalidPresence(u8),
    InvalidOam2FetchAddr(u8),
    InvalidSprCount(u8),
    FieldOutOfRange {
        field: &'static str,
        value: u8,
        max: u8,
    },
    InvalidRasterPosition {
        dot: u16,
        scanline: i16,
    },
}

Errors returned by Ppu::restore.

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

Truncated(usize)

Blob is too short for the version-1 schema.

TrailingBytes

The blob decoded completely with bytes left over (v2.9.9, NC-14: this used to be reported as Truncated at the end offset).

Fields

consumed: usize

Bytes the schema consumed.

extra: usize

Bytes left over.

UnsupportedVersion(u8)

The blob’s version byte is not understood by this build.

InvalidRegion(u8)

Region tag was not one of 0 (NTSC), 1 (PAL), 2 (Dendy).

InvalidPresence(u8)

Optional struct presence byte was something other than 0 or 1.

InvalidOam2FetchAddr(u8)

v9 OAM2 fetch address was outside the 5-bit hardware counter’s range.

oam2_fetch_addr indexes the 32-byte secondary-OAM bus, and the hardware counter it models is 5 bits wide, so anything >= 32 is a corrupt or hostile blob rather than a state this emulator can reach. Rejected at the boundary instead of masked, so a malformed file is reported rather than silently reinterpreted as a different state.

InvalidSprCount(u8)

The in-range sprite count exceeded the eight sprites secondary OAM holds.

spr_count bounds loops over the eight-slot sprite arrays (spr_x, spr_halted, the shift registers), so a value above 8 would restore without complaint and then index out of bounds on the next PPU dot – a deferred panic, and on a panic = "abort" release build a process kill from a hand-edited save. Core audit IMP-01.

FieldOutOfRange

A counter or index held a value the PPU never produces.

Each of these is incremented without a mask or used as an index, so a value past its range overflows or indexes out of bounds on a later dot. The limits are the ranges the running PPU keeps them in (fine X is the 3-bit x register; the sprite-evaluation and OAM-bus counters are reset at their wrap points). Found field by field by the v2.7.0 save_state fuzz target (fine X: ppu.rs:4788, shift overflow, in 92,496 runs) and then swept for the rest rather than left to the fuzzer one run at a time.

Fields

field: &'static str

Which field.

value: u8

The value found in the blob.

max: u8

The largest value the PPU keeps it at.

InvalidRasterPosition

The raster position is outside the region’s frame.

dot runs 0..=340 and scanline -1..=the region’s pre-render line (-1 is the power-on position). The per-dot advance only wraps at exactly those limits, so a position past either counts on until the integer overflows (a panic in dev profiles) and never produces a frame. Found by the v2.7.0 save_state fuzz target in 76,381 runs (ppu.rs:6078, dot += 1).

Fields

dot: u16

The restored dot.

scanline: i16

The restored scanline.

Trait Implementations

impl Debug for PpuSnapshotError

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

Formats the value using the given formatter.

impl Display for PpuSnapshotError

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

Formats the value using the given formatter.

impl Error for PpuSnapshotError

fn source(&self) -> Option<&(dyn Error + 'static)>

Returns the lower-level source of this error, if any.

fn description(&self) -> &str

👎Deprecated since 1.42.0:

use the Display impl or to_string()

fn cause(&self) -> Option<&dyn Error>

👎Deprecated since 1.33.0:

replaced by Error::source, which can support downcasting

fn provide<'a>(&'a self, request: &mut Request<'a>)

🔬This is a nightly-only experimental API. (error_generic_member_access)

Provides type-based access to context intended for error reports.