decode_array

Decodes a hexadecimal string into a fixed-size array, e.g. a 32-byte key from 64 hex digits.

Import

use helpers4::hex::decode_array;

Cargo feature hex (enabled by default). To compile only this module:

cargo add helpers4 --no-default-features --features hex

or in Cargo.toml:

[dependencies]
helpers4 = { version = "0.0.5", default-features = false, features = ["hex"] }

Signature

pub fn decode_array<const N: usize>(hex: &str) -> Result<[u8; N], DecodeError>

Parameters

Parameter	Type	Description
hex	&str	The hexadecimal string to decode; must encode exactly N bytes.

Returns

Result<[u8; N], DecodeError> — Ok on success, otherwise an Err: see Errors.

Errors

Same as decode_to_slice: the string must have exactly 2 * N hex digits.

Examples

use helpers4::hex::decode_array;

let key: [u8; 4] = decode_array("deadbeef")?;
assert_eq!(key, [0xde, 0xad, 0xbe, 0xef]);
assert!(decode_array::<4>("dead").is_err());

Error type: DecodeError

Why a string could not be decoded as hexadecimal.

use helpers4::hex::DecodeError;

#[non_exhaustive]
pub enum DecodeError {
    /// The string has an odd number of characters.
    OddLength,
    /// The string does not match the requested output size.
    InvalidLength {
        /// Expected number of hex characters (twice the output size).
        expected: usize,
        /// Actual number of hex characters.
        actual: usize,
    },
    /// A character that is not a hexadecimal digit.
    InvalidChar {
        /// Byte offset of the character in the input.
        index: usize,
        /// The offending character.
        found: char,
    },
}

Source

src/hex/decode_array.rs