base64.h

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#ifndef EVE_BASE64_H_INCLUDED
#define EVE_BASE64_H_INCLUDED

/**********************************************************************/
/*
 * Copyright (c) 2014-2015, Jetro AS
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONRIBUTORS ``AS IS'' AND ANY EXPRESS
 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
 * OF SUCH DAMAGE.
 *
 * This file is part of the EVE platform.
 */

 /**
 * \file
 * \brief Header file for the EVE base64 encoder / decoder
 *
 * \author DT, Jetro AS
 */ /******************************************************************/

/**
 * \defgroup base64 base64 encoder/decoder
 * \ingroup security
 * @{
 */

/**********************************************************************/
/** Static initializer of the base64 decoder structure */
#define BASE64_DEC_INIT {.step = 0,}

/**********************************************************************/
/** Static initializer of the base64 encoder structure */
#define BASE64_ENC_INIT {.step = 0,}

/**********************************************************************/
/** base64 encoder/decoder return codes */
enum base64_rc_t {
  BASE64_STATE_IDLE,         /**< No output was produced */
  BASE64_STATE_RDY,          /**< A one byte output was produced, available as encoded[0] or decoded */
  BASE64_STATE_ERROR,        /**< An error occured */
  BASE64_STATE_RDY2,         /**< Two bytes output was produced, available as encoded[1], encoded[0] */
};

/**********************************************************************/
/** base6464 decoder state */
struct base64_dec_state_t {
  uint8_t decoded;                  /**< Contains decoded character */
  uint8_t pfix;                     /**< Internally used by the decoder */
  uint8_t step;                     /**< Internally used by the decoder */
  uint8_t user;                     /**< Not used, available for calling code */
};

/**********************************************************************/
/** base6464 encoder state */
struct base64_enc_state_t {
  uint8_t encoded[2];               /**< Contains encoded characters */
  uint8_t step;                     /**< nternally used by the encoder */
  uint8_t user;                     /**< Not used, available for calling code */
};

/**********************************************************************/
/**
 * Initializes the base64 decoder structure.
 *
 * \param s pointer to the base64 decoder structure
 */
void base64_dec_init(struct base64_dec_state_t *s);

/**********************************************************************/
/**
 * Feeds the decoder with a single character.
 *
 * \param s pointer to the base64 decoder structure
 * \param ch the character to be fed to the decoder
 * \return BASE64_STATE_IDLE when the character was accepted, but no output was produced
 * \return BASE64_STATE_ERROR when the character was not accepted
 * \return BASE64_STATE_RDY whan the character was accepted and one byte of decoded data was produced
 */
enum base64_rc_t base64_dec(struct base64_dec_state_t *s, uint8_t ch);

/**********************************************************************/
/**
 * Initializes the base64 encoder structure.
 *
 * \param s pointer to the base64 encoder structure
 */
void base64_enc_init(struct base64_enc_state_t *s);

/**********************************************************************/
/**
 * Feeds the encoder with a single character.
 *
 * \param s pointer to the base64 encoder structure
 * \param ch the character to be fed to the encoder
 * \return BASE64_STATE_ERROR when the character was not accepted
 * \return BASE64_STATE_RDY whan the character was accepted and one byte of encoded data was set in encoded[0]
 * \return BASE64_STATE_RDY2 whan the character was accepted and two bytes of encoded data were set in encoded[1], encoded[0]
 */
enum base64_rc_t base64_enc(struct base64_enc_state_t *s, uint8_t ch);

/**********************************************************************/
/**
 * Tells the encoder about end of input data.
 *
 * \param s pointer to the base64 encoder structure
 * \return BASE64_STATE_IDLE when no additional data bytes were produced
 * \return BASE64_STATE_RDY whan one byte of encoded data was set in encoded[0]
 * \return BASE64_STATE_RDY2 whan two bytes of encoded data were set in encoded[1], encoded[0]
 */
enum base64_rc_t base64_enc_eof(struct base64_enc_state_t *s);

/** @} */ /* base64 */

#endif /* EVE_BASE64_H_INCLUDED */