Function base64::engine::general_purpose::decode::decode_chunk_4

fn decode_chunk_4(
    input: &[u8],
    index_at_start_of_input: usize,
    decode_table: &[u8; 256],
    output: &mut [u8],
) -> Result<(), DecodeError>

Like decode_chunk_8 but for 4 bytes of input and 3 bytes of output.