StringUtil: Add SplitStringIntoArray function template.

2 files changed, 50 insertions, 0 deletions

diff --git a/Source/Core/Common/StringUtil.h b/Source/Core/Common/StringUtil.h
index ea82581355..6e2c385df9 100644
--- a/Source/Core/Common/StringUtil.h
+++ b/Source/Core/Common/StringUtil.h
@@ -12,6 +12,7 @@
 #include <iomanip>
 #include <limits>
 #include <locale>
+#include <ranges>
 #include <span>
 #include <sstream>
 #include <string>
@@ -182,6 +183,32 @@ std::from_chars_result FromChars(std::string_view sv, std::floating_point auto&
 
 std::vector<std::string> SplitString(const std::string& str, char delim);
 
+// Returns `nullopt` if subject does not contain exactly (Count - 1) delim.
+template <std::size_t Count>
+requires(Count > 1)
+std::optional<std::array<std::string_view, Count>> SplitStringIntoArray(std::string_view subject,
+                                                                        char delim)
+{
+  std::optional<std::array<std::string_view, Count>> result;
+  result.emplace();
+
+  std::size_t index = 0;
+  for (auto&& item : subject | std::views::split(delim))
+  {
+    // Too many delim.
+    if (index == Count)
+      return std::nullopt;
+
+    (*result)[index++] = std::string_view{item};
+  }
+
+  // Too few delim.
+  if (index != Count)
+    return std::nullopt;
+
+  return result;
+}
+
 // "C:/Windows/winhelp.exe" to "C:/Windows/", "winhelp", ".exe"
 // This requires forward slashes to be used for the path separators, even on Windows.
 bool SplitPath(std::string_view full_path, std::string* path, std::string* filename,
diff --git a/Source/UnitTests/Common/StringUtilTest.cpp b/Source/UnitTests/Common/StringUtilTest.cpp
index 59ba99a436..d7c783497a 100644
--- a/Source/UnitTests/Common/StringUtilTest.cpp
+++ b/Source/UnitTests/Common/StringUtilTest.cpp
@@ -259,6 +259,29 @@ TEST(StringUtil, CaseInsensitiveContains_OverlappingMatches)
   EXPECT_TRUE(Common::CaseInsensitiveContains("ababababa", "bABa"));
 }
 
+TEST(StringUtil, SplitStringIntoArray)
+{
+  constexpr auto subject0 = "";
+  EXPECT_FALSE(SplitStringIntoArray<2>(subject0, '.').has_value());
+
+  constexpr auto subject1 = "hello";
+  EXPECT_FALSE(SplitStringIntoArray<2>(subject1, '.').has_value());
+
+  constexpr auto subject2 = "hello.world";
+  const auto split2 = SplitStringIntoArray<2>(subject2, '.');
+  EXPECT_TRUE(split2.has_value() && split2->at(1) == "world");
+  EXPECT_FALSE(SplitStringIntoArray<3>(subject2, '.').has_value());
+
+  constexpr auto subject3 = "hello.universe.";
+  EXPECT_FALSE(SplitStringIntoArray<2>(subject3, '.').has_value());
+  const auto split3 = SplitStringIntoArray<3>(subject3, '.');
+  EXPECT_TRUE(split3.has_value() && split3->at(2) == "");
+  EXPECT_FALSE(SplitStringIntoArray<4>(subject3, '.').has_value());
+
+  constexpr auto subject4 = "=";
+  EXPECT_TRUE(SplitStringIntoArray<2>(subject4, '=').has_value());
+}
+
 TEST(StringUtil, CharacterEncodingConversion)
 {
   // wstring