Implement finding multiple occurrences of a byte pattern

danielkrupinski · Dec 12, 2023 · 547c7c8 · 547c7c8
1 parent b0bae76
commit 547c7c8
Show file tree

Hide file tree

Showing 2 changed files with 20 additions and 7 deletions.
diff --git a/Source/MemorySearch/HybridPatternFinder.h b/Source/MemorySearch/HybridPatternFinder.h
@@ -10,20 +10,33 @@
 
 class HybridPatternFinder {
 public:
-    HybridPatternFinder(std::span<const std::byte> bytes, BytePattern pattern)
+    HybridPatternFinder(std::span<const std::byte> bytes, BytePattern pattern) noexcept
         : bytes{ bytes }, pattern{ pattern }
     {
     }
 
-    [[nodiscard]] const std::byte* operator()() const noexcept
+    [[nodiscard]] const std::byte* findNextOccurrence() noexcept
     {
-        PatternFinderSIMD simdFinder{ bytes, pattern };
-        if (const auto foundSIMD = simdFinder())
+        PatternFinderSIMD simdFinder{bytes, pattern};
+        if (const auto foundSIMD = simdFinder()) {
+            updateRemainingBytes(foundSIMD);
             return foundSIMD;
-        return PatternFinderScalar{ simdFinder.getNotCheckedBytes(), pattern }();
+        }
+
+        if (const auto foundScalar{PatternFinderScalar{simdFinder.getNotCheckedBytes(), pattern}()}) {
+            updateRemainingBytes(foundScalar);
+            return foundScalar;
+        }
+
+        return nullptr;
     }
 
 private:
+    void updateRemainingBytes(const std::byte* foundPosition) noexcept
+    {
+        bytes = {foundPosition + 1, bytes.data() + bytes.size()};
+    }
+
     std::span<const std::byte> bytes;
     BytePattern pattern;
 };
diff --git a/Source/MemorySearch/PatternFinder.h b/Source/MemorySearch/PatternFinder.h
@@ -24,15 +24,15 @@ struct PatternFinder {
 
     [[nodiscard]] [[NOINLINE]] SafeAddress operator()(BytePattern pattern) const noexcept
     {
-        const auto found = HybridPatternFinder{ bytes, pattern }();
+        const auto found = HybridPatternFinder{ bytes, pattern }.findNextOccurence();
         if (!found)
             notFoundHandler(pattern, bytes);
         return SafeAddress{ found };
     }
 
     [[nodiscard]] [[NOINLINE]] SafeAddress operator()(BytePattern pattern, OffsetHint offsetHint) const noexcept
     {
-        const auto foundWithHint = HybridPatternFinder{ getSliceForHint(offsetHint), pattern }();
+        const auto foundWithHint = HybridPatternFinder{ getSliceForHint(offsetHint), pattern }.findNextOccurence();
         if (foundWithHint)
             return SafeAddress{ foundWithHint };
         return operator()(pattern);