base64.h 4.64 KB
Newer Older
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135
/* base64.h
 *
 * "ASCII armor" codecs.
 */

/* nettle, low-level cryptographics library
 *
 * Copyright (C) 2002 Niels Mller, 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 "nettle-types.h"

#ifdef __cplusplus
extern "C" {
#endif

/* Name mangling */
#define base64_encode_init nettle_base64_encode_init
#define base64_encode_single nettle_base64_encode_single
#define base64_encode_update nettle_base64_encode_update
#define base64_encode_final nettle_base64_encode_final
#define base64_encode_raw nettle_base64_encode_raw
#define base64_encode_group nettle_base64_encode_group
#define base64_decode_init nettle_base64_decode_init
#define base64_decode_single nettle_base64_decode_single
#define base64_decode_update nettle_base64_decode_update
#define base64_decode_final nettle_base64_decode_final

#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_LENGTH */
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
{
  unsigned word;   /* Leftover bits */
  unsigned bits;   /* Number buffered bits */

  /* Number of padding characters encountered */
  unsigned padding;
};

void
base64_decode_init(struct base64_decode_ctx *ctx);

/* Decodes a single byte. Returns amount of output (0 or 1), or -1 on
 * errors. */
int
base64_decode_single(struct base64_decode_ctx *ctx,
		     uint8_t *dst,
		     uint8_t src);

/* Returns 1 on success, 0 on error. DST should point to an area of
 * size at least BASE64_DECODE_LENGTH(length), and for sanity
 * checking, *DST_LENGTH should be initialized to the size of that
 * area before the call. *DST_LENGTH is updated to the amount of
 * decoded output. */

Niels Möller's avatar
Niels Möller committed
136 137
/* Currently results in an assertion failure if *DST_LENGTH is
 * too small. FIXME: Return some error instead? */
138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153
int
base64_decode_update(struct base64_decode_ctx *ctx,
		     unsigned *dst_length,
		     uint8_t *dst,
		     unsigned src_length,
		     const uint8_t *src);

/* Returns 1 on success. */
int
base64_decode_final(struct base64_decode_ctx *ctx);

#ifdef __cplusplus
}
#endif

#endif /* NETTLE_BASE64_H_INCLUDED */