Let us start here, from square one. No, from Zero!

util/sigscan.h

@@ -0,0 +1,38 @@
+#pragma once
+
+#include <algorithm>
+#include <string>
+#include <vector>
+#include "windows.h"
+#include "psapi.h"
+
+intptr_t find_pattern(
+        std::vector<unsigned char> &data,
+        intptr_t base,
+        const unsigned char *pattern,
+        const char *mask,
+        intptr_t offset,
+        intptr_t usage);
+
+intptr_t find_pattern(
+        HMODULE module,
+        const unsigned char *pattern,
+        const char *mask,
+        intptr_t offset,
+        intptr_t usage);
+
+intptr_t replace_pattern(
+        HMODULE module,
+        const unsigned char *pattern,
+        const char *mask,
+        intptr_t offset,
+        intptr_t usage,
+        const unsigned char *replace_data,
+        const char *replace_mask);
+
+intptr_t replace_pattern(
+        HMODULE module,
+        const std::string &signature,
+        const std::string &replacement,
+        intptr_t offset,
+        intptr_t usage);