fn read_from()

in src/aes128gcm.rs [189:207]

• 16 lines of code
• 4 McCabe index (conditional complexity)

    fn read_from(input: &'a [u8]) -> Result<Header<'a>> {
        if input.len() < ECE_AES128GCM_HEADER_LENGTH {
            return Err(Error::HeaderTooShort);
        }

        let keyid_len = input[ECE_AES128GCM_HEADER_LENGTH - 1] as usize;
        if input.len() < ECE_AES128GCM_HEADER_LENGTH + keyid_len {
            return Err(Error::HeaderTooShort);
        }

        let salt = &input[0..ECE_SALT_LENGTH];
        let rs = BigEndian::read_u32(&input[ECE_SALT_LENGTH..]);
        if rs < ECE_AES128GCM_MIN_RS {
            return Err(Error::InvalidRecordSize);
        }
        let keyid = &input[ECE_AES128GCM_HEADER_LENGTH..ECE_AES128GCM_HEADER_LENGTH + keyid_len];

        Ok(Header { salt, rs, keyid })
    }