Constexpr find_pattern

BasedInc · Dec 13, 2022 · e9409e6 · e9409e6
1 parent 3fc7f8c
commit e9409e6
Show file tree

Hide file tree

Showing 7 changed files with 63 additions and 47 deletions.
diff --git a/include/libhat/Defines.hpp b/include/libhat/Defines.hpp
@@ -30,3 +30,9 @@
         #define LIBHAT_BLSR64(num) num & (num - 1)
     #endif
 #endif
+
+#if __cpp_if_consteval >= 202106L
+    #define LIBHAT_IF_CONSTEVAL consteval
+#else
+    #define LIBHAT_IF_CONSTEVAL (std::is_constant_evaluated())
+#endif
diff --git a/include/libhat/ScanMode.hpp b/include/libhat/ScanMode.hpp
diff --git a/include/libhat/Scanner.hpp b/include/libhat/Scanner.hpp
@@ -2,8 +2,10 @@
 
 #include <algorithm>
 #include <array>
+#include <execution>
 #include <utility>
 
+#include "Defines.hpp"
 #include "Process.hpp"
 #include "Signature.hpp"
 
@@ -47,6 +49,46 @@ namespace hat {
         std::byte* result;
     };
 
+    namespace detail {
+
+        enum class scan_mode {
+            Auto,
+            Search,
+            FastFirst,
+            AVX2,
+            AVX512,
+            Neon
+        };
+
+        template<scan_mode>
+        scan_result find_pattern(std::byte* begin, std::byte* end, signature_view signature);
+
+        template<>
+        scan_result find_pattern<scan_mode::Auto>(std::byte* begin, std::byte* end, signature_view signature);
+
+        template<>
+        constexpr scan_result find_pattern<scan_mode::FastFirst>(std::byte* begin, std::byte* end, signature_view signature) {
+            const auto firstByte = *signature[0];
+            const auto scanEnd = end - signature.size() + 1;
+
+            for (auto i = begin; i != scanEnd; i++) {
+                // Use std::find to efficiently find the first byte
+                i = std::find(std::execution::unseq, i, scanEnd, firstByte);
+                if (i == scanEnd) {
+                    break;
+                }
+                // Compare everything after the first byte
+                auto match = std::equal(signature.begin() + 1, signature.end(), i + 1, [](auto opt, auto byte) {
+                    return !opt.has_value() || *opt == byte;
+                });
+                if (match) {
+                    return i;
+                }
+            }
+            return nullptr;
+        }
+    }
+
     enum class compiler_type {
         MSVC,
         MinGW
@@ -73,9 +115,15 @@ namespace hat {
     );
 
     /// Root implementation of FindPattern
-    scan_result find_pattern(
+    constexpr scan_result find_pattern(
         std::byte*      begin,
         std::byte*      end,
         signature_view  signature
-    );
+    ) {
+        if LIBHAT_IF_CONSTEVAL {
+            return detail::find_pattern<detail::scan_mode::FastFirst>(begin, end, signature);
+        } else {
+            return detail::find_pattern<detail::scan_mode::Auto>(begin, end, signature);
+        }
+    }
 }
diff --git a/src/Scanner.cpp b/src/Scanner.cpp
@@ -1,11 +1,9 @@
 #include <libhat/Scanner.hpp>
 
 #include <map>
-#include <execution>
 
 #include <libhat/Defines.hpp>
 #include <libhat/System.hpp>
-#include <libhat/ScanMode.hpp>
 
 namespace hat {
 
@@ -90,6 +88,9 @@ namespace hat {
         }
         return find_pattern(std::to_address(data.begin()), std::to_address(data.end()), signature);
     }
+}
+
+namespace hat::detail {
 
     template<>
     [[deprecated]] scan_result find_pattern<scan_mode::Search>(std::byte* begin, std::byte* end, signature_view signature) {
@@ -103,28 +104,7 @@ namespace hat {
     }
 
     template<>
-    scan_result find_pattern<scan_mode::FastFirst>(std::byte* begin, std::byte* end, signature_view signature) {
-        const auto firstByte = *signature[0];
-        const auto scanEnd = end - signature.size() + 1;
-
-        for (auto i = begin; i != scanEnd; i++) {
-            // Use std::find to efficiently find the first byte
-            i = std::find(std::execution::unseq, i, scanEnd, firstByte);
-            if (i == scanEnd) {
-                break;
-            }
-            // Compare everything after the first byte
-            auto match = std::equal(signature.begin() + 1, signature.end(), i + 1, [](auto opt, auto byte) {
-                return !opt.has_value() || *opt == byte;
-            });
-            if (match) {
-                return i;
-            }
-        }
-        return nullptr;
-    }
-
-    scan_result find_pattern(std::byte* begin, std::byte* end, signature_view signature) {
+    scan_result find_pattern<scan_mode::Auto>(std::byte* begin, std::byte* end, signature_view signature) {
         const auto size = signature.size();
 #if defined(LIBHAT_X86)
         const auto& ext = get_system().extensions;

diff --git a/src/arch/arm/Neon.cpp b/src/arch/arm/Neon.cpp
@@ -2,9 +2,8 @@
 #ifdef LIBHAT_ARM
 
 #include <libhat/Scanner.hpp>
-#include <libhat/ScanMode.hpp>
 
-namespace hat {
+namespace hat::detail {
 
     template<>
     scan_result find_pattern<scan_mode::Neon>(std::byte* begin, std::byte* end, signature_view signature) {

diff --git a/src/arch/x86/AVX2.cpp b/src/arch/x86/AVX2.cpp
@@ -3,11 +3,10 @@
 #ifdef LIBHAT_X86
 
 #include <libhat/Scanner.hpp>
-#include <libhat/ScanMode.hpp>
 
 #include <immintrin.h>
 
-namespace hat {
+namespace hat::detail {
 
     template<>
     scan_result find_pattern<scan_mode::AVX2>(std::byte* begin, std::byte* end, signature_view signature) {

diff --git a/src/arch/x86/AVX512.cpp b/src/arch/x86/AVX512.cpp
@@ -2,11 +2,10 @@
 #ifdef LIBHAT_X86
 
 #include <libhat/Scanner.hpp>
-#include <libhat/ScanMode.hpp>
 
 #include <immintrin.h>
 
-namespace hat {
+namespace hat::detail {
 
     template<>
     scan_result find_pattern<scan_mode::AVX512>(std::byte* begin, std::byte* end, signature_view signature) {