1 files changed, 81 insertions, 0 deletions
diff --git a/windows/nsis-plugins/src/string/string.cpp b/windows/nsis-plugins/src/string/string.cpp
new file mode 100644
index 0000000000..6071e6303d
--- /dev/null
+++ b/windows/nsis-plugins/src/string/string.cpp
@@ -0,0 +1,81 @@
+#include "stdafx.h"
+#include <nsis/pluginapi.h>
+#include <stdexcept>
+#include <string>
+
+// Suppress warnings caused by broken legacy code
+#pragma warning (push)
+#pragma warning (disable: 4005)
+#include <nsis/pluginapi.h>
+#pragma warning (pop)
+
+namespace
+{
+
+std::wstring PopString()
+{
+	//
+	// NSIS functions popstring() and popstringn() require that you definitely size the buffer
+	// before popping the string. Let's do it ourselves instead.
+	//
+
+	if (!g_stacktop || !*g_stacktop)
+	{
+		throw std::runtime_error("NSIS variable stack is corrupted");
+	}
+
+	stack_t *th = *g_stacktop;
+
+	std::wstring copy(th->text);
+
+	*g_stacktop = th->next;
+	GlobalFree((HGLOBAL)th);
+
+	return copy;
+}
+
+} // anonymous namespace
+
+//
+// Find "string" "substring" begin_offset
+//
+// Return the position of "substring" in "string", starting from 'begin_offset'.
+// If the substring is not found or if an error occurs, return -1.
+//
+
+void __declspec(dllexport) NSISCALL Find
+(
+	HWND hwndParent,
+	int string_size,
+	LPTSTR variables,
+	stack_t **stacktop,
+	extra_parameters *extra,
+	...
+)
+{
+	EXDLL_INIT();
+
+	try
+	{
+		const auto searchString = PopString();
+		const auto substring = PopString();
+		const auto offset = popint();
+		const auto position = searchString.find(substring, offset);
+
+		if (std::wstring::npos == position)
+		{
+			pushint(-1);
+			return;
+		}
+
+		pushint((int)position);
+	}
+	catch (const std::exception &)
+	{
+		pushint(-1);
+	}
+	catch (...)
+	{
+		pushint(-1);
+	}
+}