Added templated versions of get_column() and bind() that inter what

type to get/bind based on the type of variable passed in.

dlib/sqlite/sqlite.h

@@ -11,6 +11,7 @@
 #include <sqlite3.h>
 #include "../smart_pointers.h"
 #include "../serialize.h"
+#include <limits>
 
 // --------------------------------------------------------------------------------------------
 
@@ -223,6 +224,31 @@ namespace dlib
             return sql_string;
         }
 
+        template <typename T>
+        typename enable_if_c<std::numeric_limits<T>::is_integer>::type get_column (
+            unsigned long idx,
+            T& item
+        ) const
+        {
+            if (sizeof(T) <= 4)
+                item = get_column_as_int(idx);
+            else
+                item = get_column_as_int64(idx);
+        }
+
+        void get_column(unsigned long idx, std::string& item) const { item = get_column_as_text(idx); }
+        void get_column(unsigned long idx, float& item      ) const { item = get_column_as_double(idx); }
+        void get_column(unsigned long idx, double& item     ) const { item = get_column_as_double(idx); }
+        void get_column(unsigned long idx, long double& item) const { item = get_column_as_double(idx); }
+
+        template <typename T>
+        typename disable_if_c<std::numeric_limits<T>::is_integer>::type get_column (
+            unsigned long idx,
+            T& item
+        ) const
+        {
+            get_column_as_object(idx, item);
+        }
 
         const std::vector<char> get_column_as_blob (
             unsigned long idx
@@ -354,6 +380,32 @@ namespace dlib
             return sqlite3_bind_parameter_index(stmt, name.c_str());
         }
 
+        template <typename T>
+        typename enable_if_c<std::numeric_limits<T>::is_integer>::type bind (
+            unsigned long idx,
+            T& item
+        ) 
+        {
+            if (sizeof(T) <= 4)
+                bind_int(idx, item);
+            else
+                bind_int64(idx, item);
+        }
+
+        void bind(unsigned long idx, std::string& item) { bind_text(idx, item); }
+        void bind(unsigned long idx, float& item      ) { bind_double(idx, item); }
+        void bind(unsigned long idx, double& item     ) { bind_double(idx, item); }
+        void bind(unsigned long idx, long double& item) { bind_double(idx, item); }
+
+        template <typename T>
+        typename disable_if_c<std::numeric_limits<T>::is_integer>::type bind (
+            unsigned long idx,
+            T& item
+        ) 
+        {
+            bind_object(idx, item);
+        }
+
         void bind_blob (
             unsigned long parameter_id,
             const std::vector<char>& item

dlib/sqlite/sqlite_abstract.h

@@ -244,6 +244,31 @@ namespace dlib
                   routines.
         !*/
 
+        template <
+            typename T
+            >
+        void get_column (
+            unsigned long idx,
+            T& item
+        ) const;
+        /*!
+            requires
+                - idx < get_num_columns()
+            ensures
+                - This function automatically selects how to extract the column data based
+                  on the type of item given. In particular:
+                    - if (T is a 32bit or smaller built in integer type) then
+                        - #item == get_column_as_int(idx)
+                    - else if (T is a 64bit built in integer type) then
+                        - #item == get_column_as_int64(idx)
+                    - else if (T is float, double, or long double) then
+                        - #item == get_column_as_double(idx)
+                    - else if (T is std::string) then
+                        - #item == get_column_as_text(idx)
+                    - else
+                        - invokes: get_column_as_object(idx, item)
+        !*/
+
         const std::vector<char> get_column_as_blob (
             unsigned long idx
         ) const;
@@ -349,6 +374,31 @@ namespace dlib
                     - returns 0
         !*/
 
+        template <
+            typename T
+            >
+        void bind (
+            unsigned long parameter_id,
+            T& item
+        ) const;
+        /*!
+            requires
+                - 1 <= parameter_id <= get_max_parameter_id()
+            ensures
+                - This function automatically selects how to bind item to a statement based
+                  on the type of item given.  In particular:
+                    - if (T is a 32bit or smaller built in integer type) then
+                        - invokes: bind_int(parameter_id, item)
+                    - else if (T is a 64bit built in integer type) then
+                        - invokes: bind_int64(parameter_id, item)
+                    - else if (T is float, double, or long double) then
+                        - invokes: bind_double(parameter_id, item)
+                    - else if (T is std::string) then
+                        - invokes: bind_text(parameter_id, item)
+                    - else
+                        - invokes: bind_object(parameter_id, item)
+        !*/
+
         void bind_blob (
             unsigned long parameter_id,
             const std::vector<char>& item