This is an implementation of all five Base X encodings described in RFC 4648. It is MIT-licensed, and written in C++17.

Published under the MIT license, see LICENSE file.

Requires GNU make, C++17-capable compiler, and Boost.Format. Cram is required to run the test suite:

$ ./configure
$ make check
$ sudo make install

If it complains about missing boost/format.hpp, tell it where your Boost.Format headers are, eg:

$ ./configure --with-boost=/usr

https://tools.ietf.org/html/rfc4648#section-4

                 Table 1: The Base 64 Alphabet

Value Encoding  Value Encoding  Value Encoding  Value Encoding
    0 A            16 Q            32 g            48 w
    1 B            17 R            33 h            49 x
    2 C            18 S            34 i            50 y
    3 D            19 T            35 j            51 z
    4 E            20 U            36 k            52 0
    5 F            21 V            37 l            53 1
    6 G            22 W            38 m            54 2
    7 H            23 X            39 n            55 3

    8 I            24 Y            40 o            56 4
    9 J            25 Z            41 p            57 5
   10 K            26 a            42 q            58 6
   11 L            27 b            43 r            59 7
   12 M            28 c            44 s            60 8
   13 N            29 d            45 t            61 9
   14 O            30 e            46 u            62 +
   15 P            31 f            47 v            63 /

                                                (pad) =

https://tools.ietf.org/html/rfc4648#section-5

    Table 2: The "URL and Filename safe" Base 64 Alphabet

Value Encoding  Value Encoding  Value Encoding  Value Encoding
    0 A            16 Q            32 g            48 w
    1 B            17 R            33 h            49 x
    2 C            18 S            34 i            50 y
    3 D            19 T            35 j            51 z
    4 E            20 U            36 k            52 0
    5 F            21 V            37 l            53 1
    6 G            22 W            38 m            54 2
    7 H            23 X            39 n            55 3

    8 I            24 Y            40 o            56 4
    9 J            25 Z            41 p            57 5
   10 K            26 a            42 q            58 6
   11 L            27 b            43 r            59 7
   12 M            28 c            44 s            60 8
   13 N            29 d            45 t            61 9
   14 O            30 e            46 u            62 - (minus)
   15 P            31 f            47 v            63 _ (underline)


                                                (pad) =

https://tools.ietf.org/html/rfc4648#section-6

                Table 3: The Base 32 Alphabet

Value Encoding  Value Encoding  Value Encoding  Value Encoding
    0 A             8 I            16 Q            24 Y
    1 B             9 J            17 R            25 Z
    2 C            10 K            18 S            26 2
    3 D            11 L            19 T            27 3
    4 E            12 M            20 U            28 4
    5 F            13 N            21 V            29 5
    6 G            14 O            22 W            30 6
    7 H            15 P            23 X            31 7

                                                (pad) =

https://tools.ietf.org/html/rfc4648#section-7

           Table 4: The "Extended Hex" Base 32 Alphabet

Value Encoding  Value Encoding  Value Encoding  Value Encoding
    0 0             8 8            16 G            24 O
    1 1             9 9            17 H            25 P
    2 2            10 A            18 I            26 Q
    3 3            11 B            19 J            27 R
    4 4            12 C            20 K            28 S
    5 5            13 D            21 L            29 T
    6 6            14 E            22 M            30 U
    7 7            15 F            23 N            31 V

                                                (pad) =

https://tools.ietf.org/html/rfc4648#section-8

                Table 5: The Base 16 Alphabet

Value Encoding  Value Encoding  Value Encoding  Value Encoding
    0 0             4 4             8 8            12 C
    1 1             5 5             9 9            13 D
    2 2             6 6            10 A            14 E
    3 3             7 7            11 B            15 F