should be it

external/duckdb/extension/parquet/include/parquet_dlba_encoder.hpp

@@ -0,0 +1,69 @@
+//===----------------------------------------------------------------------===//
+//                         DuckDB
+//
+// parquet_dlba_encoder.hpp
+//
+//
+//===----------------------------------------------------------------------===//
+
+#pragma once
+
+#include "parquet_dbp_encoder.hpp"
+#include "duckdb/common/serializer/memory_stream.hpp"
+
+namespace duckdb {
+
+class DlbaEncoder {
+public:
+	DlbaEncoder(const idx_t total_value_count_p, const idx_t total_string_size_p)
+	    : dbp_encoder(total_value_count_p), total_string_size(total_string_size_p) {
+	}
+
+public:
+	template <class T>
+	void BeginWrite(Allocator &, WriteStream &, const T &) {
+		throw InternalException("DlbaEncoder should only be used with strings");
+	}
+
+	template <class T>
+	void WriteValue(WriteStream &, const T &) {
+		throw InternalException("DlbaEncoder should only be used with strings");
+	}
+
+	void FinishWrite(WriteStream &writer) {
+		dbp_encoder.FinishWrite(writer);
+		writer.WriteData(buffer.get(), stream->GetPosition());
+	}
+
+	template <class SRC>
+	static idx_t GetStringSize(const SRC &) {
+		return 0;
+	}
+
+private:
+	DbpEncoder dbp_encoder;
+	const idx_t total_string_size;
+	AllocatedData buffer;
+	unsafe_unique_ptr<MemoryStream> stream;
+};
+
+template <>
+inline void DlbaEncoder::BeginWrite(Allocator &allocator, WriteStream &writer, const string_t &first_value) {
+	buffer = allocator.Allocate(total_string_size + 1);
+	stream = make_unsafe_uniq<MemoryStream>(buffer.get(), buffer.GetSize());
+	dbp_encoder.BeginWrite(writer, UnsafeNumericCast<int64_t>(first_value.GetSize()));
+	stream->WriteData(const_data_ptr_cast(first_value.GetData()), first_value.GetSize());
+}
+
+template <>
+inline void DlbaEncoder::WriteValue(WriteStream &writer, const string_t &value) {
+	dbp_encoder.WriteValue(writer, UnsafeNumericCast<int64_t>(value.GetSize()));
+	stream->WriteData(const_data_ptr_cast(value.GetData()), value.GetSize());
+}
+
+template <>
+inline idx_t DlbaEncoder::GetStringSize(const string_t &src_value) {
+	return src_value.GetSize();
+}
+
+} // namespace duckdb