1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44

use std::fmt;
use std::error;
use httlib_huffman::{EncoderError as HuffmanError};

/// Represents all errors that can be encountered while performing the encoding
/// of an HPACK header set.
#[derive(Debug, PartialEq)]
pub enum EncoderError {
    /// Indicates that the encoder received an invalid ASCII character and is
    /// thus unable to perform the (Huffman) encoding. Note that only ASCII
    /// characters provided in the HPACK spec should be used.
    InvalidInput,
    /// Indicates that an invalid index was provided. According to the HPACK
    /// specification, the index `0` must be treated as an invalid index number.
    /// The first valid number is `1`.
    InvalidIndex,
    /// Indicates that an invalid prefix was provided (must be [1, 8]).
    InvalidPrefix,
    /// Indicates that the value of the integer being encoded exceeds a certain
    /// threshold (5 bytes are chosen by this implementation). This can also
    /// happen while encoding too long string.
    IntegerOverflow,
}

impl From<HuffmanError> for EncoderError {
    fn from(err: HuffmanError) -> Self {
        match err {
            HuffmanError::InvalidInput => Self::InvalidInput
        }
    }
}

impl fmt::Display for EncoderError {
    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
        match self {
            Self::InvalidInput => write!(fmt, "Invalid input character."),
            Self::InvalidIndex => write!(fmt, "Invalid index."),
            Self::InvalidPrefix => write!(fmt, "Invalid prefix."),
            Self::IntegerOverflow => write!(fmt, "Too many bytes."),
        }
    }
}

impl error::Error for EncoderError {}