/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied. See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

/*
 * XSEC
 *
 * OpenSSLCryptoBase64 := Base virtual class to define a base64 encoder/decoder
 *
 * Author(s): Berin Lautenbach
 *
 * $Id: OpenSSLCryptoBase64.hpp 1894296 2021-10-15 16:12:36Z scantor $
 *
 */

#ifndef OPENSSLCRYPTOBASE64_INCLUDE
#define OPENSSLCRYPTOBASE64_INCLUDE

#include <xsec/framework/XSECDefs.hpp>
#include <xsec/enc/XSECCryptoBase64.hpp>
#include <xsec/enc/OpenSSL/OpenSSLSupport.hpp>

// OpenSSL
#if defined (XSEC_HAVE_OPENSSL)
#   include <openssl/evp.h>

/**
 * @ingroup opensslcrypto
 */
 /*\@{*/

/**
 * \brief Base64 encode/decode handler interface class.
 *
 * The XSEC library will use implementations of this interface 
 * for translating bytes to/from base64 encoding.
 *
 * Uses the EVP decode/encode routines in OpenSSL to perform the 
 * work.
 * 
 * 
 * 
 * @note Requires implementation of OpenSSL > 0.9.6e as there was a bug
 * in the Base64 decoding routines in this version and prior.
 *
 */


class XSEC_EXPORT OpenSSLCryptoBase64 : public XSECCryptoBase64 {


public :

    
    OpenSSLCryptoBase64();
    virtual ~OpenSSLCryptoBase64();

    /** @name Decoding Functions */
    //@{

    /**
     * \brief Initialise the base64 object.
     *
     * Initialises the OpenSSL decode context and gets ready for data
     * to be decoded.
     *
     */

    virtual void decodeInit(void);

    /**
     * \brief Decode some passed in data.
     *
     * Pass the encoded data through the OpenSSL base64 decode function
     * and place the data in the outData buffer.
     *
     * @note The OpenSSL library is very unkind if the output buffer is
     * not large enough.  It is the responsibility of the caller to ensure
     * the buffer will take the data.
     *
     * @param inData Pointer to the buffer holding encoded data.
     * @param inLength Length of the encoded data in the buffer
     * @param outData Buffer to place decoded data into
     * @param outLength Maximum amount of data that can be placed in
     *        the buffer.
     * @returns The number of bytes placed in the outData buffer.
     */

    virtual unsigned int decode(const unsigned char * inData, 
                                unsigned int inLength,
                                unsigned char * outData,
                                unsigned int outLength);


    /**
     * \brief Finish off a decode.
     *
     * Clean out any extra data in the OpenSSL decode context 
     * variable into the outData buffer.
     *
     * @param outData Buffer to place any remaining decoded data
     * @param outLength Max amount of data to be placed in the buffer.
     * @returns Amount of data placed in the outData buffer
     */

    virtual unsigned int decodeFinish(unsigned char * outData,
                                      unsigned int outLength);

    //@}

    /** @name Encoding Functions */
    //@{

    /**
     * \brief Initialise the base64 object for encoding
     *
     * Get the context variable ready for a base64 decode
     *
     */

    virtual void         encodeInit(void);

    /**
     * \brief Encode some passed in data.
     *
     * Pass the data through the OpenSSL Base64 encoder and place
     * the output in the outData buffer.  Will keep any "overhang"
     * data in the context buffer ready for the next pass of input 
     * data.
     *
     * @param inData Pointer to the buffer holding data to be encoded.
     * @param inLength Length of the data in the buffer
     * @param outData Buffer to place encoded data into
     * @param outLength Maximum amount of data that can be placed in
     *        the buffer.
     * @returns The number of bytes placed in the outData buffer.
     */

    virtual unsigned int encode(const unsigned char * inData, 
                                unsigned int inLength,
                                unsigned char * outData,
                                unsigned int outLength);

    /**
     * \brief Finish off an encode.
     *
     * Take any data left in the context variable, and create the
     * tail of the base64 encoding.
     *
     * @param outData Buffer to place any remaining encoded data
     * @param outLength Max amount of data to be placed in the buffer.
     * @returns Amount of data placed in the outData buffer
     */

    virtual unsigned int encodeFinish(unsigned char * outData,
                                      unsigned int outLength);  // Finish


    //@}

    /** @name Library Specific Functions */
    //@{

    /**
     * \brief Translate a base64 encoded BN to a bignum
     *
     * Take a ds:CryptoBinary number and translate to an OpenSSL
     * representation of a "big number" BIGNUM.
     *
     */
    
    static BIGNUM * b642BN(char * b64in, unsigned int len);

    /**
     * \brief Get OpenSSL encode context structure
     */

    EVP_ENCODE_CTX * getOpenSSLEncodeEVP_ENCODE_CTX(void) {return mp_ectx;}

    /**
     * \brief Get OpenSSL encode context structure
     */

    EVP_ENCODE_CTX * getOpenSSLDecodeEVP_ENCODE_CTX(void) {return mp_dctx;}

    //@}

private :

    EVP_ENCODE_CTX *mp_ectx;              // Encode context
    EVP_ENCODE_CTX *mp_dctx;              // Decode context

#if (OPENSSL_VERSION_NUMBER < 0x10100000L) || defined(LIBRESSL_VERSION_NUMBER_TOO_OLD)
    EVP_ENCODE_CTX m_ectx_store;
    EVP_ENCODE_CTX m_dctx_store;
#endif 
};

/*\@}*/

#endif /* XSEC_HAVE_OPENSSL */
#endif /* OPENSSLCRYPTOBASE64_INCLUDE */
