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Add support for Base.decode16/2 and Base.encode16/2
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Signed-off-by: Yuto Oguchi <[email protected]>
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@aiotter
aiotter committed Oct 2, 2024
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227 changes: 227 additions & 0 deletions libs/exavmlib/lib/Base.ex
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#
# This file is part of elixir-lang.
#
# Copyright 2014-2023 Elixir Contributors
# https://github.com/elixir-lang/elixir/commits/v1.17.3/lib/elixir/lib/base.ex
#
# Copyright 2024 Yuto Oguchi <[email protected]>
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
# SPDX-License-Identifier: Apache-2.0
#

defmodule Base do
@moduledoc """
This module provides data encoding and decoding functions
according to [RFC 4648](https://tools.ietf.org/html/rfc4648).
This document defines the commonly used base 16, base 32, and base
64 encoding schemes.
## 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 |
## Base 32 alphabet
| Value | Encoding | Value | Encoding | Value | Encoding | Value | Encoding |
|------:|:---------|------:|:---------|------:|:---------|------:|:---------|
| 0 | A | 9 | J | 18 | S | 27 | 3 |
| 1 | B | 10 | K | 19 | T | 28 | 4 |
| 2 | C | 11 | L | 20 | U | 29 | 5 |
| 3 | D | 12 | M | 21 | V | 30 | 6 |
| 4 | E | 13 | N | 22 | W | 31 | 7 |
| 5 | F | 14 | O | 23 | X | | |
| 6 | G | 15 | P | 24 | Y | (pad) | = |
| 7 | H | 16 | Q | 25 | Z | | |
| 8 | I | 17 | R | 26 | 2 | | |
## Base 32 (extended hex) alphabet
| Value | Encoding | Value | Encoding | Value | Encoding | Value | Encoding |
|------:|:---------|------:|:---------|------:|:---------|------:|:---------|
| 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 | (pad) | = |
| 7 | 7 | 16 | G | 25 | P | | |
| 8 | 8 | 17 | H | 26 | Q | | |
## Base 64 alphabet
| Value | Encoding | Value | Encoding | Value | Encoding | Value | Encoding |
|------:|:----------|------:|:---------|------:|:---------|------:|:---------|
| 0 | A | 17 | R | 34 | i | 51 | z |
| 1 | B | 18 | S | 35 | j | 52 | 0 |
| 2 | C | 19 | T | 36 | k | 53 | 1 |
| 3 | D | 20 | U | 37 | l | 54 | 2 |
| 4 | E | 21 | V | 38 | m | 55 | 3 |
| 5 | F | 22 | W | 39 | n | 56 | 4 |
| 6 | G | 23 | X | 40 | o | 57 | 5 |
| 7 | H | 24 | Y | 41 | p | 58 | 6 |
| 8 | I | 25 | Z | 42 | q | 59 | 7 |
| 9 | J | 26 | a | 43 | r | 60 | 8 |
| 10 | K | 27 | b | 44 | s | 61 | 9 |
| 11 | L | 28 | c | 45 | t | 62 | + |
| 12 | M | 29 | d | 46 | u | 63 | / |
| 13 | N | 30 | e | 47 | v | | |
| 14 | O | 31 | f | 48 | w | (pad) | = |
| 15 | P | 32 | g | 49 | x | | |
| 16 | Q | 33 | h | 50 | y | | |
## Base 64 (URL and filename safe) alphabet
| Value | Encoding | Value | Encoding | Value | Encoding | Value | Encoding |
|------:|:---------|------:|:---------|------:|:---------|------:|:---------|
| 0 | A | 17 | R | 34 | i | 51 | z |
| 1 | B | 18 | S | 35 | j | 52 | 0 |
| 2 | C | 19 | T | 36 | k | 53 | 1 |
| 3 | D | 20 | U | 37 | l | 54 | 2 |
| 4 | E | 21 | V | 38 | m | 55 | 3 |
| 5 | F | 22 | W | 39 | n | 56 | 4 |
| 6 | G | 23 | X | 40 | o | 57 | 5 |
| 7 | H | 24 | Y | 41 | p | 58 | 6 |
| 8 | I | 25 | Z | 42 | q | 59 | 7 |
| 9 | J | 26 | a | 43 | r | 60 | 8 |
| 10 | K | 27 | b | 44 | s | 61 | 9 |
| 11 | L | 28 | c | 45 | t | 62 | - |
| 12 | M | 29 | d | 46 | u | 63 | _ |
| 13 | N | 30 | e | 47 | v | | |
| 14 | O | 31 | f | 48 | w | (pad) | = |
| 15 | P | 32 | g | 49 | x | | |
| 16 | Q | 33 | h | 50 | y | | |
"""

@type encode_case :: :upper | :lower
@type decode_case :: :upper | :lower | :mixed

@doc """
Decodes a base 16 encoded string into a binary string.
## Options
The accepted options are:
* `:case` - specifies the character case to accept when decoding
The values for `:case` can be:
* `:upper` - only allows upper case characters (default)
* `:lower` - only allows lower case characters
* `:mixed` - allows mixed case characters
## Examples
iex> Base.decode16("666F6F626172")
{:ok, "foobar"}
iex> Base.decode16("666f6f626172", case: :lower)
{:ok, "foobar"}
iex> Base.decode16("666f6F626172", case: :mixed)
{:ok, "foobar"}
"""
@spec decode16(binary, case: decode_case) :: {:ok, binary} | :error
def decode16(string, ops \\ []) do
{:ok, decode16!(string, ops)}
rescue
ArgumentError -> :error
end

@doc """
Decodes a base 16 encoded string into a binary string.
## Options
The accepted options are:
* `:case` - specifies the character case to accept when decoding
The values for `:case` can be:
* `:upper` - only allows upper case characters (default)
* `:lower` - only allows lower case characters
* `:mixed` - allows mixed case characters
An `ArgumentError` exception is raised if the padding is incorrect or
a non-alphabet character is present in the string.
## Examples
iex> Base.decode16!("666F6F626172")
"foobar"
iex> Base.decode16!("666f6f626172", case: :lower)
"foobar"
iex> Base.decode16!("666f6F626172", case: :mixed)
"foobar"
"""
@spec decode16!(binary, case: decode_case) :: binary
def decode16!(string, opts \\ [])

def decode16!(string, _ops) when is_binary(string) and rem(byte_size(string), 2) == 0 do
# TODO: support :case option
:binary.decode_hex(string)
end

def decode16!(string, _opts) when is_binary(string) do
raise ArgumentError,
"string given to decode has wrong length. An even number of bytes was expected, got: #{byte_size(string)}. " <>
"Double check your string for unwanted characters or pad it accordingly"
end

@doc """
Encodes a binary string into a base 16 encoded string.
## Options
The accepted options are:
* `:case` - specifies the character case to use when encoding
The values for `:case` can be:
* `:upper` - uses upper case characters (default)
* `:lower` - uses lower case characters
## Examples
iex> Base.encode16("foobar")
"666F6F626172"
iex> Base.encode16("foobar", case: :lower)
"666f6f626172"
"""
@spec encode16(binary, case: encode_case) :: binary
def encode16(data, opts \\ []) do
case Keyword.get(opts, :case, :upper) do
:upper -> :binary.encode_hex(data, :uppercase)
:lower -> :binary.encode_hex(data, :lowercase)
end
end
end
1 change: 1 addition & 0 deletions libs/exavmlib/lib/CMakeLists.txt
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Expand Up @@ -24,6 +24,7 @@ include(BuildElixir)

set(ELIXIR_MODULES
AVMPort
Base
Bitwise
Code
Console
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