base64.h

it is know of https implement source code

/**
 * \file base64.h
 */
#ifndef XYSSL_BASE64_H
#define XYSSL_BASE64_H

#define XYSSL_ERR_BASE64_BUFFER_TOO_SMALL               -0x0010
#define XYSSL_ERR_BASE64_INVALID_CHARACTER              -0x0012

#ifdef __cplusplus
extern "C" {
#endif

/**
 * \brief          Encode a buffer into base64 format
 *
 * \param dst      destination buffer
 * \param dlen     size of the buffer
 * \param src      source buffer
 * \param slen     amount of data to be encoded
 *
 * \return         0 if successful, or XYSSL_ERR_BASE64_BUFFER_TOO_SMALL.
 *                 *dlen is always updated to reflect the amount
 *                 of data that has (or would have) been written.
 *
 * \note           Call this function with *dlen = 0 to obtain the
 *                 required buffer size in *dlen
 */
int base64_encode( unsigned char *dst, int *dlen,
                   unsigned char *src, int  slen );

/**
 * \brief          Decode a base64-formatted buffer
 *
 * \param dst      destination buffer
 * \param dlen     size of the buffer
 * \param src      source buffer
 * \param slen     amount of data to be decoded
 *
 * \return         0 if successful, XYSSL_ERR_BASE64_BUFFER_TOO_SMALL, or
 *                 XYSSL_ERR_BASE64_INVALID_DATA if the input data is not
 *                 correct. *dlen is always updated to reflect the amount
 *                 of data that has (or would have) been written.
 *
 * \note           Call this function with *dlen = 0 to obtain the
 *                 required buffer size in *dlen
 */
int base64_decode( unsigned char *dst, int *dlen,
                   unsigned char *src, int  slen );

/**
 * \brief          Checkup routine
 *
 * \return         0 if successful, or 1 if the test failed
 */
int base64_self_test( int verbose );

#ifdef __cplusplus
}
#endif

#endif /* base64.h */