include/base64.h

   1 /*
   2  * Copyright (C) 1996-2014 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
  13 #include <nettle/base64.h>
  14
  15 #else /* Base64 functions copied from Nettle 3.0 under GPLv2, with adjustments */
  16
  17 #ifdef __cplusplus
  18 extern "C" {
  19 #endif
  20
  21 // Decoding functions
  22
  23 /// Maximum length of output for base64_decode_update.
  24 /// We have at most 6 buffered bits, and a total of (length + 1) * 6 bits.
  25 #   define BASE64_DECODE_LENGTH(length) ((((length) + 1) * 6) / 8)
  26
  27 struct base64_decode_ctx
  28 {
  29     unsigned word;   /* Leftover bits */
  30     unsigned bits;   /* Number buffered bits */
  31
  32     /* Number of padding characters encountered */
  33     unsigned padding;
  34 };
  35
  36 void base64_decode_init(struct base64_decode_ctx *ctx);
  37
  38 /* Returns 1 on success, 0 on error. DST should point to an area of
  39  * size at least BASE64_DECODE_LENGTH(length). The amount of data
  40  * generated is returned in *DST_LENGTH.
  41  */
  42 int base64_decode_update(struct base64_decode_ctx *ctx,
  43                          size_t *dst_length,
  44                          uint8_t *dst,
  45                          size_t src_length,
  46                          const uint8_t *src);
  47
  48 /* Returns 1 on success. */
  49 int base64_decode_final(struct base64_decode_ctx *ctx);
  50
  51 // Encoding functions
  52
  53 /* Maximum length of output for base64_encode_update. NOTE: Doesn't
  54  * include any padding that base64_encode_final may add. */
  55 /* We have at most 4 buffered bits, and a total of (4 + length * 8) bits. */
  56 #   define BASE64_ENCODE_LENGTH(length) (((length) * 8 + 4)/6)
  57
  58 /* Maximum length of output generated by base64_encode_final. */
  59 #   define BASE64_ENCODE_FINAL_LENGTH 3
  60
  61 /* Exact length of output generated by base64_encode_raw, including
  62  * padding.
  63  */
  64 #   define BASE64_ENCODE_RAW_LENGTH(length) ((((length) + 2)/3)*4)
  65
  66 struct base64_encode_ctx
  67 {
  68     unsigned word;   /* Leftover bits */
  69     unsigned bits;  /* Number of bits, always 0, 2, or 4. */
  70 };
  71
  72 void base64_encode_init(struct base64_encode_ctx *ctx);
  73
  74 /// Encodes a single byte. Returns amount of output (always 1 or 2).
  75 size_t base64_encode_single(struct base64_encode_ctx *ctx, uint8_t *dst, uint8_t src);
  76
  77 /* Returns the number of output characters. DST should point to an
  78  * area of size at least BASE64_ENCODE_LENGTH(length).
  79  */
  80 size_t base64_encode_update(struct base64_encode_ctx *ctx, uint8_t *dst, size_t length, const uint8_t *src);
  81
  82 /// DST should point to an area of size at least BASE64_ENCODE_FINAL_LENGTH
  83 size_t base64_encode_final(struct base64_encode_ctx *ctx, uint8_t *dst);
  84
  85 #ifdef __cplusplus
  86 }
  87 #endif
  88
  89 #endif /* HAVE_NETTLE_BASE64_H */
  90
  91 /// Calculate the buffer size required to hold the encoded form of
  92 /// a string of length 'decodedLen' including all terminator bytes.
  93 #   define base64_encode_len(length) (BASE64_ENCODE_LENGTH(length)+BASE64_ENCODE_FINAL_LENGTH+1)
  94
  95 #endif /* _SQUID_BASE64_H */
  96