Add getOutputMessage() accessor to Statement (#45)

Author: fdcastel

src/fb-cpp/Statement.h

@@ -408,6 +408,14 @@ namespace fbcpp
 			return outMetadata;
 		}
 
+		///
+		/// @brief Provides direct access to the raw output message buffer.
+		///
+		std::vector<std::byte>& getOutputMessage() noexcept
+		{
+			return outMessage;
+		}
+
 		///
 		/// @brief Returns the type classification reported by the server.
 		///

src/test/Statement.cpp

@@ -336,6 +336,29 @@ BOOST_AUTO_TEST_CASE(descriptorMetadataFields)
 	BOOST_CHECK(inDescriptors[0].alias.empty());
 }
 
+BOOST_AUTO_TEST_CASE(getOutputMessageContainsFetchedValueAtMetadataOffset)
+{
+	const auto database = getTempFile("Statement-getOutputMessageContainsFetchedValueAtMetadataOffset.fdb");
+
+	Attachment attachment{CLIENT, database, AttachmentOptions().setCreateDatabase(true)};
+	FbDropDatabase attachmentDrop{attachment};
+
+	Transaction transaction{attachment};
+	Statement stmt{attachment, transaction, "select 42 from rdb$database"};
+
+	auto& outMsg = stmt.getOutputMessage();
+	BOOST_CHECK(!outMsg.empty());
+
+	const auto valueOffset = stmt.getOutputDescriptors()[0].offset;
+
+	BOOST_REQUIRE(stmt.execute(transaction));
+	BOOST_CHECK_EQUAL(stmt.getInt32(0).value(), 42);
+
+	BOOST_REQUIRE_GE(outMsg.size(), valueOffset + sizeof(std::int32_t));
+	const auto* data = &outMsg[valueOffset];
+	BOOST_CHECK_EQUAL(*reinterpret_cast<const std::int32_t*>(data), 42);
+}
+
 BOOST_AUTO_TEST_SUITE_END()