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/* base32.h -- Encode binary data using printable characters.
Copyright (C) 2004, 2005, 2006, 2010 Free Software Foundation, Inc.
Written by Ondřej Surý & Simon Josefsson.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software Foundation,
Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
#ifndef _BASE32_H_
#define _BASE32_H_
/* Get size_t. */
#include <stddef.h>
/* Get bool. */
#include <stdbool.h>
/*!
* \brief Counts the size of the Base32-encoded output for given input length.
*
* \note This uses that the expression (n+(k-1))/k means the smallest
* integer >= n/k, i.e., the ceiling of n/k.
*/
#define BASE32_LENGTH(inlen) ((((inlen) + 4) / 5) * 8)
/*!
* \brief Checks if the given character belongs to the Base32 alphabet.
*
* \param ch Character to check.
*
* \retval true if \a ch belongs to the Base32 alphabet.
* \retval false otherwise.
*/
extern bool isbase32(char ch);
/*!
* \brief Encodes the given character array using Base32 encoding.
*
* If \a outlen is less than BASE32_LENGTH(\a inlen), the function writes as
* many bytes as possible to the output buffer. If \a outlen is more than
* BASE32_LENGTH(\a inlen), the output will be zero-terminated.
*
* \param in Input array of characters.
* \param inlen Length of the input array.
* \param out Output buffer.
* \param outlen Size of the output buffer.
*/
extern void base32_encode(const char *in, size_t inlen, char *out,
size_t outlen);
/*!
* \brief Encodes the given character array using Base32 encoding and allocates
* space for the output.
*
* \param in Input array of characters.
* \param inlen Length of the input array.
* \param out Output buffer.
*
* \return Size of the allocated output buffer (0 if failed).
*/
extern size_t base32_encode_alloc(const char *in, size_t inlen, char **out);
/*!
* \brief Decodes the given character array in Base32 encoding.
*
* If \a *outlen is too small, as many bytes as possible will be written to
* \a out. On return, \a *outlen holds the length of decoded bytes in \a out.
*
* \note As soon as any non-alphabet characters are encountered, decoding is
* stopped and false is returned. This means that, when applicable, you
* must remove any line terminators that is part of the data stream before
* calling this function.
*
* \param in Input array of characters.
* \param inlen Length of the input array.
* \param out Output buffer.
* \param outlen Size of the output buffer.
*
* \retval true if decoding was successful, i.e. if the input was valid base32
* data.
* \retval false otherwise.
*/
extern bool base32_decode(const char *in, size_t inlen, char *out,
size_t *outlen);
/*!
* \brief Allocate an output buffer and decode the base32 encoded data to it.
*
* On return, the size of the decoded data is stored in \a *outlen. \a outlen
* may be NULL, if the caller is not interested in the decoded length. \a *out
* may be NULL to indicate an out of memory error, in which case \a *outlen
* contains the size of the memory block needed.
*
* \param in Input array of characters.
* \param inlen Length of the input array.
* \param out Output buffer. \a *out may be NULL to indicate an out of memory
* error in which case \a *outlen contains the size of the memory
* block needed
* \param outlen Size of the output buffer. May be NULL, if the caller is not
* interested in the decoded length
*
* \retval true on successful decoding and memory allocation errors. (Use the
* \a *out and \a *outlen parameters to differentiate between
* successful decoding and memory error.)
* \retval false if the input was invalid, in which case \a *out is NULL and
* \a *outlen is undefined.
*/
extern bool base32_decode_alloc(const char *in, size_t inlen, char **out,
size_t *outlen);
#endif /* _BASE32_H_ */
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