lib/base32.h

   1 /* base32.h -- Encode binary data using printable characters.
   2    Copyright (C) 2004-2006, 2009-2024 Free Software Foundation, Inc.
   3    Adapted from Simon Josefsson's base64 code by Gijs van Tulder.
   4
   5    This file is free software: you can redistribute it and/or modify
   6    it under the terms of the GNU Lesser General Public License as
   7    published by the Free Software Foundation; either version 2.1 of the
   8    License, or (at your option) any later version.
   9
  10    This file is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13    GNU Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public License
  16    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  17
  18 #ifndef BASE32_H
  19 #define BASE32_H
  20
  21 /* This file uses _GL_INLINE_HEADER_BEGIN.  */
  22 #if !_GL_CONFIG_H_INCLUDED
  23  #error "Please include config.h first."
  24 #endif
  25
  26 /* Get idx_t.  */
  27 #include <idx.h>
  28
  29 /* Pacify GCC in isubase32.  */
  30 #if defined __GNUC__ && 4 < __GNUC__ + (3 <= __GNUC_MINOR__)
  31 # pragma GCC diagnostic ignored "-Wtype-limits"
  32 #endif
  33
  34 _GL_INLINE_HEADER_BEGIN
  35 #ifndef BASE32_INLINE
  36 # define BASE32_INLINE _GL_INLINE
  37 #endif
  38
  39 #ifdef __cplusplus
  40 extern "C" {
  41 #endif
  42
  43 /* This uses that the expression (n+(k-1))/k means the smallest
  44    integer >= n/k, i.e., the ceiling of n/k.  */
  45 #define BASE32_LENGTH(inlen) ((((inlen) + 4) / 5) * 8)
  46
  47 struct base32_decode_context
  48 {
  49   int i;
  50   char buf[8];
  51 };
  52
  53 extern signed char const base32_to_int[256];
  54
  55 BASE32_INLINE bool
  56 isubase32 (unsigned char ch)
  57 {
  58   return ch < sizeof base32_to_int && 0 <= base32_to_int[ch];
  59 }
  60
  61 BASE32_INLINE bool
  62 isbase32 (char ch)
  63 {
  64   return isubase32 (ch);
  65 }
  66
  67 extern void base32_encode (const char *restrict in, idx_t inlen,
  68                            char *restrict out, idx_t outlen);
  69
  70 extern idx_t base32_encode_alloc (const char *in, idx_t inlen, char **out);
  71
  72 /* Initialize decode-context buffer, CTX.  */
  73 BASE32_INLINE void
  74 base32_decode_ctx_init (struct base32_decode_context *ctx)
  75 {
  76   ctx->i = 0;
  77 }
  78
  79 extern bool base32_decode_ctx (struct base32_decode_context *ctx,
  80                                const char *restrict in, idx_t inlen,
  81                                char *restrict out, idx_t *outlen);
  82
  83 extern bool base32_decode_alloc_ctx (struct base32_decode_context *ctx,
  84                                      const char *in, idx_t inlen,
  85                                      char **out, idx_t *outlen);
  86
  87 #define base32_decode(in, inlen, out, outlen) \
  88         base32_decode_ctx (NULL, in, inlen, out, outlen)
  89
  90 #define base32_decode_alloc(in, inlen, out, outlen) \
  91         base32_decode_alloc_ctx (NULL, in, inlen, out, outlen)
  92
  93 #ifdef __cplusplus
  94 }
  95 #endif
  96
  97 _GL_INLINE_HEADER_END
  98
  99 #endif /* BASE32_H */