blob support with std::vector<T>

Author: aminroosta

hdr/sqlite_modern_cpp.h

@@ -6,6 +6,7 @@
 #include <ctime>
 #include <tuple>
 #include <memory>
+#include <vector>
 
 #ifdef _MODERN_SQLITE_BOOST_OPTIONAL_SUPPORT
 #include <boost/optional.hpp>
@@ -188,17 +189,27 @@ namespace sqlite {
 		}
 
 		template <typename Type>
-		using is_sqlite_value = std::integral_constant<
+		struct is_sqlite_value : public std::integral_constant<
 			bool,
 			std::is_floating_point<Type>::value
 			|| std::is_integral<Type>::value
 			|| std::is_same<std::string, Type>::value
 			|| std::is_same<std::u16string, Type>::value
 			|| std::is_same<sqlite_int64, Type>::value
-		>;
+		> { };
+		template <typename Type>
+		struct is_sqlite_value< std::vector<Type> > : public std::integral_constant<
+			bool,
+			std::is_floating_point<Type>::value
+			|| std::is_integral<Type>::value
+			|| std::is_same<sqlite_int64, Type>::value
+    > { };
+
 
 		template<typename T> friend database_binder::chain_type& operator <<(database_binder::chain_type& db, const T& val);
 		template<typename T> friend void get_col_from_db(database_binder& db, int inx, T& val);
+		template<typename T> friend database_binder::chain_type& operator <<(database_binder::chain_type& db, const std::vector<T>& val);
+		template<typename T> friend void get_col_from_db(database_binder& db, int inx, std::vector<T>& val);
 		template<typename T> friend T operator++(database_binder& db, int);
 
 
@@ -410,6 +421,27 @@ namespace sqlite {
 		}
 	}
 
+	// vector<T>
+	template<typename T> inline database_binder::chain_type& operator<<(database_binder::chain_type& db, const std::vector<T>& vec) {
+		void const* buf = reinterpret_cast<void const *>(vec.data());
+		int bytes = vec.size() * sizeof(T);
+		int hresult;
+		if((hresult = sqlite3_bind_blob(db->_stmt.get(), db->_inx, buf, bytes, SQLITE_TRANSIENT)) != SQLITE_OK) {
+			exceptions::throw_sqlite_error(hresult);
+		}
+		++db->_inx;
+		return db;
+	}
+	template<typename T> inline void get_col_from_db(database_binder& db, int inx, std::vector<T>& vec) {
+		if(sqlite3_column_type(db._stmt.get(), inx) == SQLITE_NULL) {
+			vec.clear();
+		} else {
+			int bytes = sqlite3_column_bytes(db._stmt.get(), inx);
+			T const* buf = reinterpret_cast<T const *>(sqlite3_column_blob(db._stmt.get(), inx));
+			vec = std::vector<T>(buf, buf + bytes/sizeof(T));
+		}
+	}
+
 	// std::string
 	template<> inline void get_col_from_db(database_binder& db, int inx, std::string & s) {
 		if(sqlite3_column_type(db._stmt.get(), inx) == SQLITE_NULL) {

tests/blob_example.cc

@@ -0,0 +1,65 @@
+#include <iostream>
+#include <cstdlib>
+#include <unistd.h>
+#include <vector>
+#include <string>
+#include <sqlite_modern_cpp.h>
+using namespace  sqlite;
+using namespace std;
+
+int main()
+{
+	try
+	{
+		database db(":memory:");
+
+		db << "CREATE TABLE person (name TEXT, numbers BLOB);";
+		db << "INSERT INTO person VALUES (?, ?)" << "bob" << vector<int> { 1, 2, 3, 4};
+		db << "INSERT INTO person VALUES (?, ?)" << "jack" << vector<char> { '1', '2', '3', '4'};
+		db << "INSERT INTO person VALUES (?, ?)" << "sara" << vector<double> { 1.0, 2.0, 3.0, 4.0};
+
+		vector<int> numbers_bob;
+		db << "SELECT numbers from person where name = ?;" << "bob" >> numbers_bob;
+
+		if(numbers_bob.size() != 4 || numbers_bob[0] != 1
+        || numbers_bob[1] != 2 || numbers_bob[2] != 3 || numbers_bob[3] != 4 ) {
+			cout << "Bad result on line " << __LINE__ << endl;
+			exit(EXIT_FAILURE);
+		}
+    //else { for(auto e : numbers_bob) cout << e << ' '; cout << endl; }
+
+		vector<char> numbers_jack;
+		db << "SELECT numbers from person where name = ?;" << "jack" >> numbers_jack;
+
+		if(numbers_jack.size() != 4 || numbers_jack[0] != '1'
+        || numbers_jack[1] != '2' || numbers_jack[2] != '3' || numbers_jack[3] != '4' ) {
+			cout << "Bad result on line " << __LINE__ << endl;
+			exit(EXIT_FAILURE);
+		}
+    //else { for(auto e : numbers_jack) cout << e << ' '; cout << endl; }
+
+		vector<double> numbers_sara;
+		db << "SELECT numbers from person where name = ?;" << "sara" >> numbers_sara;
+
+		if(numbers_sara.size() != 4 || numbers_sara[0] != 1
+        || numbers_sara[1] != 2 || numbers_sara[2] != 3 || numbers_sara[3] != 4 ) {
+			cout << "Bad result on line " << __LINE__ << endl;
+			exit(EXIT_FAILURE);
+		}
+    //else { for(auto e : numbers_sara) cout << e << ' '; cout << endl; }
+
+	}
+	catch(sqlite_exception e)
+	{
+		cout << "Unexpected error " << e.what() << endl;
+		exit(EXIT_FAILURE);
+	}
+	catch(...)
+	{
+		cout << "Unknown error\n";
+		exit(EXIT_FAILURE);
+	}
+
+	cout << "OK\n";
+	exit(EXIT_SUCCESS);
+}