Fix up base64 docs

//! Utilities for base64 coding

//!

//! See manual page of [`EVP_EncodeInit`] for more information on the specific base64 variant.

//!

//! [`EVP_EncodeInit`]: https://www.openssl.org/docs/man1.1.1/man3/EVP_EncodeInit.html

//! Base64 encoding support.

use cvt_n;

use error::ErrorStack;

use ffi;

use libc::c_int;

/// Encodes a given block of bytes to base64.

/// Encodes a slice of bytes to a base64 string.

///

/// This corresponds to [`EVP_EncodeBlock`].

///

/// # Panics

///

/// Panics if the input length or computed output length

/// overflow a signed C integer.

/// Panics if the input length or computed output length overflow a signed C integer.

///

/// [`EVP_EncodeBlock`]: https://www.openssl.org/docs/man1.1.1/man3/EVP_DecodeBlock.html

pub fn encode_block(src: &[u8]) -> String {

    assert!(src.len() <= c_int::max_value() as usize);

    let src_len = src.len() as c_int;

    }

}

/// Decodes a given base64-encoded text to bytes.

/// Decodes a base64-encoded string to bytes.

///

/// This corresponds to [`EVP_DecodeBlock`].

///

/// # Panics

///

/// Panics if the input length or computed output length

/// overflow a signed C integer.

/// Panics if the input length or computed output length overflow a signed C integer.

///

/// [`EVP_DecodeBlock`]: https://www.openssl.org/docs/man1.1.1/man3/EVP_DecodeBlock.html

pub fn decode_block(src: &str) -> Result<Vec<u8>, ErrorStack> {

    let src = src.trim();