[External] [mojo-stdlib] Add b16encode and b16decode to base64 module…

… (#39561)

[External] [mojo-stdlib] Add b16encode and b16decode to base64 module

This change adds `b16encode` and `b16decode` to the `base64` module, as
well as relevant tests.

The initial implementation is simple and can be optimized in future
iterations (if needed).

modularml#474

Co-authored-by: Kern Handa <[email protected]>
Closes modularml#2584
MODULAR_ORIG_COMMIT_REV_ID: 341c7f3656c041f37d76e6c8b382b92c8762f74e

docs/changelog.md

@@ -137,6 +137,10 @@ what we publish.
 - Base64 decoding support has been added.
  ([PR #2364](https://github.com/modularml/mojo/pull/2364) by [@mikowals](https://github.com/mikowals))
 
+- Add Base16 encoding and decoding support.
+ ([PR #2584](https://github.com/modularml/mojo/pull/2584)
+ by [@kernhanda](https://github.com/kernhanda))
+
 - Add `repr()` function and `Representable` trait.
  ([PR #2361](https://github.com/modularml/mojo/pull/2361) by [@gabrieldemarmiesse](https://github.com/gabrieldemarmiesse))
 

stdlib/src/base64/__init__.mojo

@@ -12,4 +12,4 @@
 # ===----------------------------------------------------------------------=== #
 """Implements the base64 package."""
 
-from .base64 import b64encode, b64decode
+from .base64 import b64encode, b64decode, b16encode, b16decode

stdlib/src/base64/base64.mojo

@@ -151,3 +151,85 @@ fn b64decode(str: String) -> String:
 
  p.append(0)
  return p
+
+
+# ===----------------------------------------------------------------------===#
+# b16encode
+# ===----------------------------------------------------------------------===#
+
+
+fn b16encode(str: String) -> String:
+ """Performs base16 encoding on the input string.
+
+ Args:
+ str: The input string.
+
+ Returns:
+ Base16 encoding of the input string.
+ """
+ alias lookup = "0123456789ABCDEF"
+ var b16chars = lookup.unsafe_ptr()
+
+ var length = len(str)
+ var out = List[Int8](capacity=length * 2 + 1)
+
+ @parameter
+ @always_inline
+ fn str_bytes(idx: Int) -> Int:
+ return int(str.unsafe_ptr().bitcast[DType.uint8]()[idx])
+
+ for i in range(length):
+ var str_byte = str_bytes(i)
+ var hi = str_byte >> 4
+ var lo = str_byte & 0b1111
+ out.append(b16chars[hi])
+ out.append(b16chars[lo])
+
+ out.append(0)
+
+ return String(out^)
+
+
+# ===----------------------------------------------------------------------===#
+# b16decode
+# ===----------------------------------------------------------------------===#
+
+
+@always_inline
+fn b16decode(str: String) -> String:
+ """Performs base16 decoding on the input string.
+
+ Args:
+ str: A base16 encoded string.
+
+ Returns:
+ The decoded string.
+ """
+
+ # TODO: Replace with dict literal when possible
+ @parameter
+ @always_inline
+ fn decode(c: String) -> Int:
+ var char_val = ord(c)
+
+ if ord("A") <= char_val <= ord("Z"):
+ return char_val - ord("A") + 10
+ elif ord("a") <= char_val <= ord("z"):
+ return char_val - ord("a") + 10
+ elif ord("0") <= char_val <= ord("9"):
+ return char_val - ord("0")
+
+ return -1
+
+ var n = len(str)
+ debug_assert(n % 2 == 0, "Input length must be divisible by 2")
+
+ var p = List[Int8](capacity=int(n / 2) + 1)
+
+ for i in range(0, n, 2):
+ var hi = str[i]
+ var lo = str[i + 1]
+ p.append(decode(hi) << 4 | decode(lo))
+
+ p.append(0)
+ return p

stdlib/test/base64/test_base64.mojo

@@ -12,7 +12,7 @@
 # ===----------------------------------------------------------------------=== #
 # RUN: %mojo %s
 
-from base64 import b64encode, b64decode
+from base64 import b64encode, b64decode, b16encode, b16decode
 from testing import assert_equal
 
 
@@ -52,6 +52,42 @@ def test_b64decode():
  assert_equal(b64decode("QUJDREVGYWJjZGVm"), "ABCDEFabcdef")
 
 
+def test_b16encode():
+ assert_equal(b16encode("a"), "61")
+
+ assert_equal(b16encode("fo"), "666F")
+
+ assert_equal(b16encode("Hello Mojo!!!"), "48656C6C6F204D6F6A6F212121")
+
+ assert_equal(b16encode("Hello 🔥!!!"), "48656C6C6F20F09F94A5212121")
+
+ assert_equal(
+ b16encode("the quick brown fox jumps over the lazy dog"),
+ "74686520717569636B2062726F776E20666F78206A756D7073206F76657220746865206C617A7920646F67",
+ )
+
+ assert_equal(b16encode("ABCDEFabcdef"), "414243444546616263646566")
+
+
+def test_b16decode():
+ assert_equal(b16decode("61"), "a")
+
+ assert_equal(b16decode("666F"), "fo")
+
+ assert_equal(b16decode("48656C6C6F204D6F6A6F212121"), "Hello Mojo!!!")
+
+ assert_equal(b16decode("48656C6C6F20F09F94A5212121"), "Hello 🔥!!!")
+
+ assert_equal(
+ b16encode("the quick brown fox jumps over the lazy dog"),
+ "74686520717569636B2062726F776E20666F78206A756D7073206F76657220746865206C617A7920646F67",
+ )
+
+ assert_equal(b16decode("414243444546616263646566"), "ABCDEFabcdef")
+
+
 def main():
  test_b64encode()
  test_b64decode()
+ test_b16encode()
+ test_b16decode()