From 65827826fe305040d43ac477e24e3b5b03536a6b Mon Sep 17 00:00:00 2001
From: Tim Ledbetter <timledbetter@gmail.com>
Date: Fri, 12 Jan 2024 21:34:22 +0000
Subject: [PATCH] AK: Add `CharacterTypes::is_ascii_base36_digit()`

This can be used to validate the string passed to
`parse_ascii_base36_digit()`.
---
 AK/CharacterTypes.h             |  6 ++++++
 Tests/AK/TestCharacterTypes.cpp | 11 +++++++++++
 2 files changed, 17 insertions(+)

diff --git a/AK/CharacterTypes.h b/AK/CharacterTypes.h
index 6748a505c3..2f558a8cf8 100644
--- a/AK/CharacterTypes.h
+++ b/AK/CharacterTypes.h
@@ -45,6 +45,11 @@ constexpr bool is_ascii_alphanumeric(u32 code_point)
     return is_ascii_alpha(code_point) || is_ascii_digit(code_point);
 }
 
+constexpr bool is_ascii_base36_digit(u32 code_point)
+{
+    return is_ascii_digit(code_point) || (code_point >= 'A' && code_point <= 'Z') || (code_point >= 'a' && code_point <= 'z');
+}
+
 constexpr bool is_ascii_binary_digit(u32 code_point)
 {
     return code_point == '0' || code_point == '1';
@@ -176,6 +181,7 @@ constexpr u32 to_ascii_base36_digit(u32 digit)
 using AK::is_ascii;
 using AK::is_ascii_alpha;
 using AK::is_ascii_alphanumeric;
+using AK::is_ascii_base36_digit;
 using AK::is_ascii_binary_digit;
 using AK::is_ascii_blank;
 using AK::is_ascii_c0_control;
diff --git a/Tests/AK/TestCharacterTypes.cpp b/Tests/AK/TestCharacterTypes.cpp
index 209816d906..87cc394160 100644
--- a/Tests/AK/TestCharacterTypes.cpp
+++ b/Tests/AK/TestCharacterTypes.cpp
@@ -67,6 +67,17 @@ TEST_CASE(is_ascii_alphanumeric)
     compare_bool_output_over(ASCII, isalnum, is_ascii_alphanumeric);
 }
 
+TEST_CASE(is_ascii_base36_digit)
+{
+    constexpr Array valid_base36_digits { '0', '9', 'A', 'Z', 'a', 'z' };
+    for (auto valid_base36_digit : valid_base36_digits)
+        EXPECT_EQ(is_ascii_base36_digit(valid_base36_digit), true);
+
+    constexpr Array invalid_base36_digits { '/', ':', '@', '[', '`', '{' };
+    for (auto invalid_base36_digit : invalid_base36_digits)
+        EXPECT_EQ(is_ascii_base36_digit(invalid_base36_digit), false);
+}
+
 TEST_CASE(is_ascii_blank)
 {
     compare_bool_output_over(ASCII, isblank, is_ascii_blank);