base32::core -
Expanding basic base32 maps
package require Tcl 8.4
package require base32::core ? 0.1 ?
::base32::core::define map forwvar backwvar ivar
::base32::core::valid string pattern mvar
This package provides generic commands for the construction of full
base32 mappings from a basic mapping listing just the codes and
associated characters. The full mappings, regular and inverse, created
here map to and from bit sequences, and also handle the partial
mappings at the end of a string.
This is in essence an internal package to be used by implementors of a
base32 en- and decoder. A regular user has no need of this package at
all.
-
::base32::core::define map forwvar backwvar ivar
-
This command computes full forward and backward (inverse) mappings
from the basic map and stores them in the variables named by
forwvar and backwvar resp. It also constructs a regexp
pattern for the detection of invalid characters in supposedly base32
encoded input and stores it in the variable named by ivar.
-
::base32::core::valid string pattern mvar
-
This command checks if the input string is a valid base32
encoded string, based on the pattern of invalid characters as
generated by ::base32::core::define, and some other general
rules.
The result of the command is a boolean flag. Its value is True
for a valid string, and False otherwise. In the latter
case an error message describing the problem with the input is stored
into the variable named by mvar. The variable is not touched if
the input was found to be valid.
The rules checked by the command, beyond rejection of bad characters,
are:
- The length of the input is not a multiple of eight,
- The padding appears not at the end of input, but in the middle,
- The padding has not of length six, four, three, or one characters,
This document, and the package it describes, will undoubtedly contain
bugs and other problems.
Please report such in the category
base32 of the
http://sourceforge.net/tracker/?group_id=12883.
Please also report any ideas for enhancements you may have for either
package and/or documentation.
base32