Enum DecodeError 

pub enum DecodeError {
    Eof(BitReaderEof),
    Prefix(PrefixError),
    GreenSymbolOutOfRange {
        symbol: usize,
        alphabet_size: usize,
    },
    ColorCacheIndexOutOfRange {
        index: usize,
        cache_size: usize,
    },
    BackwardReferenceUnderflow {
        position: usize,
        distance: usize,
    },
    BackwardReferenceOverflow {
        position: usize,
        length: usize,
        total_pixels: usize,
    },
    MetaPrefix(MetaPrefixError),
    EmptyEntropyImage {
        prefix_image_width: u32,
        prefix_image_height: u32,
    },
    MetaPrefixIndexOutOfRange {
        meta_prefix_code: usize,
        num_prefix_groups: usize,
    },
    DuplicateTransform,
}

Errors raised while decoding the §5.2 per-pixel ARGB stream.

Variants

Eof(BitReaderEof)

The bit reader hit EOF mid-symbol or mid-extra-bits.

Prefix(PrefixError)

A prefix-code symbol read failed.

GreenSymbolOutOfRange

§6.2.3: the GREEN symbol S was at or beyond the alphabet size 256 + 24 + color_cache_size.

Fields

symbol: usize

The offending symbol value.

alphabet_size: usize

The GREEN alphabet size.

ColorCacheIndexOutOfRange

§5.2.3: a color-cache code resolved to an index outside the cache, or a color-cache code was read for a stream with no color cache.

Fields

index: usize

The resolved cache index.

cache_size: usize

The configured cache size (0 when the cache is disabled).

BackwardReferenceUnderflow

§5.2.2: a backward-reference copy reached back beyond the start of the already-decoded pixels.

Fields

position: usize

The pixel position the copy was attempted at.

distance: usize

The scan-line distance D that underflowed.

BackwardReferenceOverflow

§5.2.2: a backward-reference run would write past the end of the image (more pixels than remain).

Fields

position: usize

The pixel position the copy started at.

length: usize

The copy length L.

total_pixels: usize

The total number of pixels in the image.

MetaPrefix(MetaPrefixError)

§5.2.3 / §6.2.2: reading the color-cache info, meta-prefix bit, the entropy-image header, or one of the per-group prefix-code groups failed.

EmptyEntropyImage

§6.2.2: the entropy image’s prefix_image_width / prefix_image_height were zero (a degenerate header that yields no blocks to select groups for).

Fields

prefix_image_width: u32

The derived entropy-image width.

prefix_image_height: u32

The derived entropy-image height.

MetaPrefixIndexOutOfRange

§6.2.2: a pixel’s block selected a meta-prefix code at or beyond num_prefix_groups — i.e. an index larger than the maximum the entropy image was supposed to contain. This can only arise from a logic error in the caller, but is checked rather than panicking.

Fields

meta_prefix_code: usize

The selected meta-prefix code.

num_prefix_groups: usize

The number of prefix-code groups that were read.

DuplicateTransform

§4 / §7.2: a transform type appeared more than once in the optional-transform list. The spec mandates each transform is used at most once.

Trait Implementations

impl Clone for DecodeError

fn clone(&self) -> DecodeError

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for DecodeError

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

Formats the value using the given formatter.

impl Display for DecodeError

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

Formats the value using the given formatter.

impl Eq for DecodeError

impl Error for DecodeError

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.

impl From<BitReaderEof> for DecodeError

fn from(e: BitReaderEof) -> Self

Converts to this type from the input type.

impl From<DecodeError> for AlphError

fn from(e: DecodeError) -> Self

Converts to this type from the input type.

impl From<DecodeError> for Error

fn from(e: DecodeError) -> Self

Converts to this type from the input type.

impl From<MetaPrefixError> for DecodeError

fn from(e: MetaPrefixError) -> Self

Converts to this type from the input type.

impl From<PrefixError> for DecodeError

fn from(e: PrefixError) -> Self

Converts to this type from the input type.

impl PartialEq for DecodeError

fn eq(&self, other: &DecodeError) -> 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 StructuralPartialEq for DecodeError