[comment {-*- tcl -*- doctools manpage}]
[manpage_begin base32::hex n 0.1]
[keywords base32]
[keywords hex]
[keywords rfc3548]
[copyright {Public domain}]
[moddesc   {Base32 encoding}]
[titledesc {base32 extended hex encoding}]
[category  {Text processing}]
[require Tcl 8.4]
[require base32::core [opt 0.1]]
[require base32::hex  [opt 0.1]]
[description]
[para]

This package provides commands for encoding and decoding of strings
into and out of the extended hex base32 encoding as specified in the
RFC 3548bis draft.

[section API]

[list_begin definitions]

[call [cmd ::base32::hex::encode] [arg string]]

This command encodes the given [arg string] in extended hex base32 and
returns the encoded string as its result. The result may be padded
with the character [const =] to signal a partial encoding at the end
of the input string.

[call [cmd ::base32::hex::decode] [arg estring]]

This commands takes the [arg estring] and decodes it under the
assumption that it is a valid extended hex base32 encoded string. The
result of the decoding is returned as the result of the command.

[para]

Note that while the encoder will generate only uppercase characters
this decoder accepts input in lowercase as well.

[para]

The command will always throw an error whenever encountering
conditions which signal some type of bogus input, namely if

[list_begin enumerated]
[enum] the input contains characters which are not valid output
       of a extended hex base32 encoder,
[enum] the length of the input is not a multiple of eight,
[enum] padding appears not at the end of input, but in the middle,
[enum] the padding has not of length six, four, three, or one characters,
[list_end]
[list_end]

[section {Code map}]

The code map used to convert 5-bit sequences is shown below, with the
numeric id of the bit sequences to the left and the character used to
encode it to the right. The important feature of the extended hex
mapping is that the first 16 codes map to the digits and hex
characters.

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

[vset CATEGORY base32]
[include ../common-text/feedback.inc]
[manpage_end]