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/* base64.h
*
* "ASCII armor" codecs.
*/
/* nettle, low-level cryptographics library
*
* Copyright (C) 2002 Niels Möller, Dan Egnor
*
* The nettle library is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation; either version 2.1 of the License, or (at your
* option) any later version.
*
* The nettle library 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 Lesser General Public
* License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with the nettle library; see the file COPYING.LIB. If not, write to
* the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
* MA 02111-1307, USA.
*/
#ifndef NETTLE_BASE64_H_INCLUDED
#define NETTLE_BASE64_H_INCLUDED
#include <inttypes.h>
#define BASE64_BINARY_BLOCK_SIZE 3
#define BASE64_TEXT_BLOCK_SIZE 4
/* Base64 encoding */
/* Maximum length of output for base64_encode_update. NOTE: Doesn't
* include any padding that base64_encode_final may add. */
/* We have at most 4 buffered bits, and a total of (4 + length * 8) bits. */
#define BASE64_ENCODE_LENGTH(length) (((length) * 8 + 4)/6)
/* Maximum lengbth of output generated by base64_encode_final. */
#define BASE64_ENCODE_FINAL_LENGTH 3
/* Exact length of output generated by base64_encode_raw, including
* padding. */
#define BASE64_ENCODE_RAW_LENGTH(length) ((((length) + 2)/3)*4)
struct base64_encode_ctx
{
unsigned word; /* Leftover bits */
unsigned bits; /* Number of bits, always 0, 2, or 4. */
};
void
base64_encode_init(struct base64_encode_ctx *ctx);
/* Encodes a single byte. Returns amount of output (always 1 or 2). */
unsigned
base64_encode_single(struct base64_encode_ctx *ctx,
uint8_t *dst,
uint8_t src);
/* Returns the number of output characters. DST should point to an
* area of size at least BASE64_ENCODE_LENGTH(length). */
unsigned
base64_encode_update(struct base64_encode_ctx *ctx,
uint8_t *dst,
unsigned length,
const uint8_t *src);
/* DST should point to an area of size at least
* BASE64_ENCODE_FINAL_SIZE */
unsigned
base64_encode_final(struct base64_encode_ctx *ctx,
uint8_t *dst);
/* Lower level functions */
/* Encodes a string in one go, including any padding at the end.
* Generates exactly BASE64_ENCODE_RAW_LENGTH(length) bytes of output.
* Supports overlapped operation, if src <= dst. */
void
base64_encode_raw(uint8_t *dst, unsigned length, const uint8_t *src);
void
base64_encode_group(uint8_t *dst, uint32_t group);
/* Base64 decoding */
/* Maximum length of output for base64_decode_update. */
/* We have at most 6 buffered bits, and a total of (length + 1) * 6 bits. */
#define BASE64_DECODE_LENGTH(length) ((((length) + 1) * 6) / 8)
struct base64_decode_ctx
{
enum
{
BASE64_DECODE_OK,
BASE64_DECODE_ERROR,
BASE64_DECODE_END
} status;
unsigned word; /* Leftover bits */
unsigned bits; /* Number buffered bits */
};
void
base64_decode_init(struct base64_decode_ctx *ctx);
/* Decodes a single byte. Returns amount of output (always 0 or 1).
* FIXME: What to return on errors? */
unsigned
base64_decode_single(struct base64_decode_ctx *ctx,
uint8_t *dst,
uint8_t src);
/* Returns the number of output characters. DST should point to an
* area of size at least BASE64_DECODE_LENGTH(length). */
unsigned
base64_decode_update(struct base64_decode_ctx *ctx,
uint8_t *dst,
unsigned length,
const uint8_t *src);
/* Returns 1 on success. */
int
base64_decode_status(struct base64_decode_ctx *ctx);
#endif /* NETTLE_BASE64_H_INCLUDED */
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