From 431f4eee66fab75c758d7c09f04327823fed0099 Mon Sep 17 00:00:00 2001
From: assiduous <assiduous@diligentgraphics.com>
Date: Tue, 9 Jan 2024 18:58:51 -0800
Subject: [PATCH] Parsing tools: added RefinePreprocessorDirective function

---
 Common/interface/ParsingTools.hpp             | 41 ++++++++++++++++++-
 .../src/Common/ParsingToolsTest.cpp           | 30 +++++++++++++-
 2 files changed, 69 insertions(+), 2 deletions(-)

diff --git a/Common/interface/ParsingTools.hpp b/Common/interface/ParsingTools.hpp
index 2c5459ad1..8a59d1851 100644
--- a/Common/interface/ParsingTools.hpp
+++ b/Common/interface/ParsingTools.hpp
@@ -1,5 +1,5 @@
 /*
- *  Copyright 2019-2022 Diligent Graphics LLC
+ *  Copyright 2019-2024 Diligent Graphics LLC
  *
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
@@ -1084,6 +1084,45 @@ std::string GetTokenContext(const TokenIterType& Start,
     return Ctx.str();
 }
 
+/// Extracts the preprocessor directive from the given range
+template <typename InteratorType>
+std::string RefinePreprocessorDirective(const InteratorType& Start, const InteratorType& End) noexcept
+{
+    // # /* Comment */ define
+    // ^
+    // Pos
+    if (Start == End || *Start != '#')
+        return "";
+
+    const auto DirectiveStart = SkipDelimitersAndComments(Start + 1, End, " \t", SKIP_COMMENT_FLAG_MULTILINE);
+    // # /* Comment */ define
+    //                 ^
+    //          DirectiveStart
+
+    const auto DirectiveEnd = SkipIdentifier(DirectiveStart, End);
+    // # /* Comment */ define
+    //                       ^
+    //                      Pos
+
+    return std::string{DirectiveStart, DirectiveEnd};
+}
+
+inline std::string RefinePreprocessorDirective(const std::string& Str) noexcept
+{
+    return RefinePreprocessorDirective(Str.begin(), Str.end());
+}
+
+inline std::string RefinePreprocessorDirective(const char* Str, size_t Len = 0) noexcept
+{
+    if (Str == nullptr)
+        return "";
+
+    if (Len == 0)
+        Len = strlen(Str);
+
+    return RefinePreprocessorDirective(Str, Str + Len);
+}
+
 } // namespace Parsing
 
 } // namespace Diligent
diff --git a/Tests/DiligentCoreTest/src/Common/ParsingToolsTest.cpp b/Tests/DiligentCoreTest/src/Common/ParsingToolsTest.cpp
index a43d88682..02493d04b 100644
--- a/Tests/DiligentCoreTest/src/Common/ParsingToolsTest.cpp
+++ b/Tests/DiligentCoreTest/src/Common/ParsingToolsTest.cpp
@@ -1,5 +1,5 @@
 /*
- *  Copyright 2019-2022 Diligent Graphics LLC
+ *  Copyright 2019-2024 Diligent Graphics LLC
  *
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
@@ -1341,4 +1341,32 @@ TEST(Common_ParsingTools, GetTokenContext)
     }
 }
 
+
+TEST(Common_ParsingTools, RefinePreprocessorDirective)
+{
+    auto TestRefine = [](const std::string& Str, const char* RefStr) {
+        EXPECT_STREQ(RefinePreprocessorDirective(Str).c_str(), RefStr);
+        EXPECT_STREQ(RefinePreprocessorDirective(Str.c_str()).c_str(), RefStr);
+        EXPECT_STREQ(RefinePreprocessorDirective(Str.c_str(), Str.length()).c_str(), RefStr);
+    };
+
+    TestRefine("", "");
+    TestRefine(" ", "");
+    TestRefine("#", "");
+    TestRefine("# ", "");
+    TestRefine("# \t", "");
+    TestRefine("# \n", "");
+    TestRefine("# /*Comment*/", "");
+
+    TestRefine("define", "");
+    TestRefine("#\ndefine", "");
+    TestRefine("# // define", "");
+    TestRefine(",define", "");
+
+    TestRefine("#define", "define");
+    TestRefine("#   define", "define");
+    TestRefine("#  \t define", "define");
+    TestRefine("#  \t /* Comment*/ define", "define");
+}
+
 } // namespace