More refactors in basebuffer

luprex/cpp/core/streambuffer.hpp

@@ -245,8 +245,9 @@ public:
 
 using LuaValue = BaseLuaValue<eng::string>;
 
-class StreamBufferCore {
+class StreamBufferConfig {
 protected:
+    using string_type = eng::string;
     void *basebuffer_malloc(size_t size) { return eng::malloc(size); }
     void basebuffer_free(void *p) { eng::free(p); }
     void clear_error_flags() { }
@@ -255,7 +256,7 @@ protected:
     void raise_integer_truncated() { throw StreamIntegerTruncated(); }
 };
 
-class StreamBuffer : public eng::nevernew, public BaseBuffer<StreamBufferCore, eng::string> {
+class StreamBuffer : public eng::nevernew, public BaseBuffer<StreamBufferConfig> {
 public:
     using BaseBuffer::BaseBuffer;