Merge pull request #32 from aminroosta/blob

Blob support with `std::vector<T>`

README.md

@@ -93,22 +93,22 @@ It is possible to retain and reuse statments this will keep the query plan and i
 		int tmp = 8;
 		ps << tmp;
 
-		// now you can execute it with `operator>>` or `execute()`. 
+		// now you can execute it with `operator>>` or `execute()`.
 		// If the statment was executed once it will not be executed again when it goes out of scope.
 		// But beware that it will execute on destruction if it wasn't executed!
 		ps >> [&](int a,int b){ ... };
 
 		// after a successfull execution the statment needs to be reset to be execute again. This will reset the bound values too!
 		ps.reset();
-		
+
 		// If you dont need the returned values you can execute it like this
 		ps.execute(); // the statment will not be reset!
 
 		// there is a convinience operator to execute and reset in one go
 		ps++;
 
 		// To disable the execution of a statment when it goes out of scope and wasn't used
-		ps.used(true); // or false if you want it to execute even if it was used 
+		ps.used(true); // or false if you want it to execute even if it was used
 
 		// Usage Example:
 
@@ -131,9 +131,9 @@ Take this example on how to deal with a database backup using SQLITEs own functi
 
 		auto con = db.connection();		// get a handle to the DB we want to backup in our scope
 										// this way we are sure the DB is open and ok while we backup
-		
+
 		// Init Backup and make sure its freed on exit or exceptions!
-		auto state = 
+		auto state =
 			std::unique_ptr<sqlite3_backup,decltype(&sqlite3_backup_finish)>(
 			sqlite3_backup_init(backup.connection().get(), "main", con.get(), "main"),
 			sqlite3_backup_finish
@@ -166,7 +166,7 @@ You can use transactions with `begin;`, `commit;` and `rollback;` commands.
 			<< u"jack"
 			<< 68.5;
 		db << "commit;"; // commit all the changes.
-                
+
 		db << "begin;"; // begin another transaction ....
 		db << "insert into user (age,name,weight) values (?,?,?);" // utf16 string
 			<< 19
@@ -176,6 +176,24 @@ You can use transactions with `begin;`, `commit;` and `rollback;` commands.
 
 ```
 
+Blob
+=====
+Use `std::vector<T>` to store and retrieve blob data.  
+`T` could be `char,short,int,long,long long, float or double`.
+
+```c++
+		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 (?, ?)" << "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;
+
+		db << "SELECT numbers from person where name = ?;" << "sara" >> [](vector<double> numbers_sara){
+		    for(auto e : numbers_sara) cout << e << ' '; cout << endl;
+		};
+```
+
 Dealing with NULL values
 =====
 If you have databases where some rows may be null, you can use boost::optional to retain the NULL value between C++ variables and the database. Note that you must enable the boost support by defining _MODERN_SQLITE_BOOST_OPTIONAL_SUPPORT befor importing the header.
@@ -184,45 +202,45 @@ If you have databases where some rows may be null, you can use boost::optional t
 
 	#define _MODERN_SQLITE_BOOST_OPTIONAL_SUPPORT
 	#include <sqlite_modern_cpp.h>
-	
+
 	struct User {
 		long long _id;
 		boost::optional<int> age;
 		boost::optional<string> name;
 		boost::optional<real> weight;
 	};
-	
+
 	{
 		User user;
 		user.name = "bob";
-		
+
 		// Same database as above
 		database db("dbfile.db");
-		
+
 		// Here, age and weight will be inserted as NULL in the database.
 		db << "insert into user (age,name,weight) values (?,?,?);"
 			<< user.age
 			<< user.name
 			<< user.weight;
-			
+
 		user._id = db.last_insert_rowid();
 	}
-	
+
 	{
 		// Here, the User instance will retain the NULL value(s) from the database.
 		db << "select _id,age,name,weight from user where age > ? ;"
 			<< 18
 			>> [&](long long id,
-				boost::optional<int> age, 
+				boost::optional<int> age,
 				boost::optional<string> name
 				boost::optional<real> weight) {
-			
+
 			User user;
 			user._id = id;
 			user.age = age;
 			user.name = move(name);
 			user.weight = weight;
-			
+
 			cout << "id=" << user._id
 				<< " age = " << (user.age ? to_string(*user.age) ? string("NULL"))
 				<< " name = " << (user.name ? *user.name : string("NULL"))

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);
 
 
@@ -414,6 +425,27 @@ 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 +1,69 @@
+#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 {
+			//db << "SELECT numbers from person where name = ?;" << "sara" >> [](vector<double> numbers_sara){
+			    //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);
+}