base2base

Presentation

Convert strings representing numbers between different bases.

Dependencies

None except Lua 5.3.

Tests require cwtest.

Usage

You should not use base36. But let's say you have legacy code to work with and need to convert binary from and to base36:

local base2base = require "base2base"
local alphabet_b36 = base2base.ALPHABET_B62:sub(1,36)
local from_b36 = base2base.converter(alphabet_b36, base2base.ALPHABET_B256)
local to_b36 = base2base.converter(base2base.ALPHABET_B256, alphabet_b36)
local bin = from_b36("yolo42")
assert(to_b36(bin) == "yolo42")

You can also use the library to check if the string is a valid representation for a given base:

assert(from_b36:validate("f00b4r"))
assert(not from_b36:validate("f00+b4r"))

For hexadecimal, there are faster functions available directly in the module.

local bin = base2base.from_hex("1234dead")
assert(base2base.to_hex(bin) == "1234dead")
assert(base2base.is_hex("1234dead"))

There are also helpers for base36, so you can do this:

local bin = base2base.from_b36("yolo42")
assert(base2base.to_b36(bin) == "yolo42")
assert(base2base.is_b36("yolo42"))

Finally, there are helpers for padded base64 and its base64 URL variant:

base2base.to_b64("Ma") -- "TWE="
base2base.from_b64("TWE=") -- "Ma"
base2base.to_b64url("Ma") -- "TWE="
base2base.from_b64url("TWE=") -- "Ma"

There are no is_* validation helpers for base64.

Copyright

Copyright (c) 2016-2022 Pierre Chapuis