1use core::convert::Infallible;
2use core::fmt::{self, Display};
3
4use crate::consts::QOI_MAGIC;
5
6/// Errors that can occur during encoding or decoding.
7#[derive(Debug)]
8pub enum Error {
9 /// Leading 4 magic bytes don't match when decoding
10 InvalidMagic { magic: u32 },
11 /// Invalid number of channels: expected 3 or 4
12 InvalidChannels { channels: u8 },
13 /// Invalid color space: expected 0 or 1
14 InvalidColorSpace { colorspace: u8 },
15 /// Invalid image dimensions: can't be empty or larger than 400Mp
16 InvalidImageDimensions { width: u32, height: u32 },
17 /// Image dimensions are inconsistent with image buffer length
18 InvalidImageLength { size: usize, width: u32, height: u32 },
19 /// Output buffer is too small to fit encoded/decoded image
20 OutputBufferTooSmall { size: usize, required: usize },
21 /// Input buffer ended unexpectedly before decoding was finished
22 UnexpectedBufferEnd,
23 /// Invalid stream end marker encountered when decoding
24 InvalidPadding,
25 #[cfg(feature = "std")]
26 /// Generic I/O error from the wrapped reader/writer
27 IoError(std::io::Error),
28}
29
30/// Alias for [`Result`](std::result::Result) with the error type of [`Error`].
31pub type Result<T> = core::result::Result<T, Error>;
32
33impl Display for Error {
34 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
35 match *self {
36 Self::InvalidMagic { magic } => {
37 write!(f, "invalid magic: expected {:?}, got {:?}", QOI_MAGIC, magic.to_be_bytes())
38 }
39 Self::InvalidChannels { channels } => {
40 write!(f, "invalid number of channels: {}", channels)
41 }
42 Self::InvalidColorSpace { colorspace } => {
43 write!(f, "invalid color space: {} (expected 0 or 1)", colorspace)
44 }
45 Self::InvalidImageDimensions { width, height } => {
46 write!(f, "invalid image dimensions: {}x{}", width, height)
47 }
48 Self::InvalidImageLength { size, width, height } => {
49 write!(f, "invalid image length: {} bytes for {}x{}", size, width, height)
50 }
51 Self::OutputBufferTooSmall { size, required } => {
52 write!(f, "output buffer size too small: {} (required: {})", size, required)
53 }
54 Self::UnexpectedBufferEnd => {
55 write!(f, "unexpected input buffer end while decoding")
56 }
57 Self::InvalidPadding => {
58 write!(f, "invalid padding (stream end marker mismatch)")
59 }
60 #[cfg(feature = "std")]
61 Self::IoError(ref err) => {
62 write!(f, "i/o error: {}", err)
63 }
64 }
65 }
66}
67
68#[cfg(feature = "std")]
69impl std::error::Error for Error {}
70
71impl From<Infallible> for Error {
72 fn from(_: Infallible) -> Self {
73 unreachable!()
74 }
75}
76
77#[cfg(feature = "std")]
78impl From<std::io::Error> for Error {
79 fn from(err: std::io::Error) -> Self {
80 Self::IoError(err)
81 }
82}
83