Initial commit

arm7/source/loader/InverseKmpMatcher.h

@@ -0,0 +1,39 @@
+#pragma once
+#include "common.h"
+
+template <typename T, u32 PatternLength>
+class InverseKmpMatcher
+{
+    const T* _pattern;
+    u8 _prefixFunc[PatternLength];
+public:
+    consteval InverseKmpMatcher(const T(&pattern)[PatternLength])
+        : _pattern(pattern)
+    {
+        _prefixFunc[0] = 0;
+        int k = 0;
+        for (u32 q = 1; q < PatternLength; q++)
+        {
+            while (k > 0 && pattern[k] != pattern[q])
+                k = _prefixFunc[k - 1];
+            if (pattern[k] == pattern[q])
+                k++;
+            _prefixFunc[q] = k;
+        }
+    }
+
+    int FindFirstOccurance(const T* data, u32 length) const
+    {
+        int q = 0;
+        for (u32 i = 0; i < length; i++)
+        {
+            while (q > 0 && ~_pattern[q] != data[i])
+                q = _prefixFunc[q - 1];
+            if (~_pattern[q] == data[i])
+                q++;
+            if (q == PatternLength)
+                return i - q + 1;
+        }
+        return -1;
+    }
+};