include/base64.h

   1 /*
   2  * Copyright (C) 1996-2021 The Squid Software Foundation and contributors
   3  *
   4  * Squid software is distributed under GPLv2+ license and includes
   5  * contributions from numerous individuals and organizations.
   6  * Please see the COPYING and CONTRIBUTORS files for details.
   7  */
   8
   9 #ifndef _SQUID_BASE64_H
  10 #define _SQUID_BASE64_H
  11
  12 #if HAVE_NETTLE_BASE64_H && HAVE_NETTLE34_BASE64
  13 #include <nettle/base64.h>
  14
  15 #else /* Base64 functions copied from Nettle 3.4 under GPLv2, with adjustments */
  16
  17 /* base64.h
  18
  19    Base-64 encoding and decoding.
  20
  21    Copyright (C) 2002 Niels Möller, Dan Egnor
  22
  23    This file is part of GNU Nettle.
  24
  25    GNU Nettle is free software: you can redistribute it and/or
  26    modify it under the terms of either:
  27
  28      * the GNU Lesser General Public License as published by the Free
  29        Software Foundation; either version 3 of the License, or (at your
  30        option) any later version.
  31
  32    or
  33
  34      * the GNU General Public License as published by the Free
  35        Software Foundation; either version 2 of the License, or (at your
  36        option) any later version.
  37
  38    or both in parallel, as here.
  39
  40    GNU Nettle is distributed in the hope that it will be useful,
  41    but WITHOUT ANY WARRANTY; without even the implied warranty of
  42    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  43    General Public License for more details.
  44
  45    You should have received copies of the GNU General Public License and
  46    the GNU Lesser General Public License along with this program.  If
  47    not, see http://www.gnu.org/licenses/.
  48 */
  49
  50 #ifdef __cplusplus
  51 extern "C" {
  52 #endif
  53
  54 /* Base64 encoding */
  55
  56 /* Maximum length of output for base64_encode_update. NOTE: Doesn't
  57  * include any padding that base64_encode_final may add. */
  58 /* We have at most 4 buffered bits, and a total of (4 + length * 8) bits. */
  59 #define BASE64_ENCODE_LENGTH(length) (((length) * 8 + 4)/6)
  60
  61 /* Maximum length of output generated by base64_encode_final. */
  62 #define BASE64_ENCODE_FINAL_LENGTH 3
  63
  64 /* Exact length of output generated by base64_encode_raw, including
  65  * padding. */
  66 #define BASE64_ENCODE_RAW_LENGTH(length) ((((length) + 2)/3)*4)
  67
  68 struct base64_encode_ctx
  69 {
  70     const char *alphabet;    /* Alphabet to use for encoding */
  71     unsigned short word;     /* Leftover bits */
  72     unsigned char bits;      /* Number of bits, always 0, 2, or 4. */
  73 };
  74
  75 /* Initialize encoding context for base-64 */
  76 void
  77 base64_encode_init(struct base64_encode_ctx *ctx);
  78
  79 /* Initialize encoding context for URL safe alphabet, RFC 4648. */
  80 void
  81 base64url_encode_init(struct base64_encode_ctx *ctx);
  82
  83 /* Encodes a single byte. Returns amount of output (always 1 or 2). */
  84 size_t
  85 base64_encode_single(struct base64_encode_ctx *ctx,
  86                      char *dst,
  87                      uint8_t src);
  88
  89 /* Returns the number of output characters. DST should point to an
  90  * area of size at least BASE64_ENCODE_LENGTH(length). */
  91 size_t
  92 base64_encode_update(struct base64_encode_ctx *ctx,
  93                      char *dst,
  94                      size_t length,
  95                      const uint8_t *src);
  96
  97 /* DST should point to an area of size at least
  98  * BASE64_ENCODE_FINAL_LENGTH */
  99 size_t
 100 base64_encode_final(struct base64_encode_ctx *ctx,
 101                     char *dst);
 102
 103 /* Lower level functions */
 104
 105 /* Encodes a string in one go, including any padding at the end.
 106  * Generates exactly BASE64_ENCODE_RAW_LENGTH(length) bytes of output.
 107  * Supports overlapped operation, if src <= dst.
 108  * TODO: Use of overlap is deprecated, if needed there should be a separate public function
 109  * to do that.*/
 110 void
 111 base64_encode_raw(char *dst, size_t length, const uint8_t *src);
 112
 113 void
 114 base64_encode_group(char *dst, uint32_t group);
 115
 116 /* Base64 decoding */
 117
 118 /* Maximum length of output for base64_decode_update. */
 119 /* We have at most 6 buffered bits, and a total of (length + 1) * 6 bits. */
 120 #define BASE64_DECODE_LENGTH(length) ((((length) + 1) * 6) / 8)
 121
 122 struct base64_decode_ctx
 123 {
 124     const signed char *table; /* Decoding table */
 125     unsigned short word;      /* Leftover bits */
 126     unsigned char bits;       /* Number buffered bits */
 127
 128     /* Number of padding characters encountered */
 129     unsigned char padding;
 130 };
 131
 132 /* Initialize decoding context for base-64 */
 133 void
 134 base64_decode_init(struct base64_decode_ctx *ctx);
 135
 136 /* Initialize encoding context for URL safe alphabet, RFC 4648. */
 137 void
 138 base64url_decode_init(struct base64_decode_ctx *ctx);
 139
 140 /* Decodes a single byte. Returns amount of output (0 or 1), or -1 on
 141  * errors. */
 142 int
 143 base64_decode_single(struct base64_decode_ctx *ctx,
 144                      uint8_t *dst,
 145                      char src);
 146
 147 /* Returns 1 on success, 0 on error. DST should point to an area of
 148  * size at least BASE64_DECODE_LENGTH(length). The amount of data
 149  * generated is returned in *DST_LENGTH. */
 150 int
 151 base64_decode_update(struct base64_decode_ctx *ctx,
 152                      size_t *dst_length,
 153                      uint8_t *dst,
 154                      size_t src_length,
 155                      const char *src);
 156
 157 /* Returns 1 on success. */
 158 int
 159 base64_decode_final(struct base64_decode_ctx *ctx);
 160
 161 #ifdef __cplusplus
 162 }
 163 #endif
 164
 165 #endif /* HAVE_NETTLE_BASE64_H && HAVE_NETTLE34_BASE64 */
 166
 167 /// Calculate the buffer size required to hold the encoded form of
 168 /// a string of length 'decodedLen' including all terminator bytes.
 169 #   define base64_encode_len(length) (BASE64_ENCODE_LENGTH(length)+BASE64_ENCODE_FINAL_LENGTH+1)
 170
 171 #endif /* _SQUID_BASE64_H */
 172