Added conversion from column_value to span<byte>

snej · May 15, 2024 · d889411 · d889411
1 parent 7ca844e
commit d889411
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Showing 2 changed files with 17 additions and 10 deletions.
diff --git a/include/sqnice/query.hh b/include/sqnice/query.hh
@@ -450,12 +450,6 @@ namespace sqnice {
     /** Represents a single column of a query row; returned by `query::row[]`. */
     class column_value : sqnice::noncopyable {
     public:
-        /// Gets the value as type `T`.
-        template <typename T> T get() const noexcept;
-
-        /// Implicit conversion to type `T`, for assignment or passing as a parameter.
-        template <typename T> operator T() const noexcept  {return get<T>();} // NOLINT(*-explicit-constructor)
-
         /// The data type of the column value.
         data_type type() const noexcept;
         bool not_null() const noexcept                  {return type() != data_type::null;}
@@ -464,7 +458,10 @@ namespace sqnice {
         /// The length in bytes of a text or blob value.
         size_t size_bytes() const noexcept;
 
-        // The following are just the specializations of get<T>() ...
+        /// Implicit conversion to type `T`, for assignment or passing as a parameter.
+        template <typename T> operator T() const noexcept  {return get<T>();} // NOLINT(*-explicit-constructor)
+
+        // `get()` returns the value as any of various types, depending on what it's assigned to.
 
         template <std::signed_integral T>
         T get() const noexcept {
@@ -492,8 +489,10 @@ namespace sqnice {
         template<std::same_as<std::string> T> T get() const noexcept {
             return std::string(get<std::string_view>());
         }
+        template<std::same_as<std::span<const std::byte>> T> T get() const noexcept;
         template<std::same_as<const void*> T> T get() const noexcept;
         template<std::same_as<blob> T> T get() const noexcept;
+
         template<std::same_as<null_type> T> T get() const noexcept      {return ignore;}
 
         template <typename U>

diff --git a/src/query.cc b/src/query.cc
@@ -76,7 +76,7 @@ namespace sqnice {
     statement::statement(statement const& other) noexcept
     :checking(other)
     ,impl_(other.impl_)
-    { 
+    {
         clear_bindings();
     }
 
@@ -263,7 +263,7 @@ namespace sqnice {
         int rc;
         if (value.data)
             rc = sqlite3_bind_blob64(stmt(), idx, value.data, value.size,
-                                                  copy ? SQLITE_TRANSIENT : SQLITE_STATIC);
+                                     copy ? SQLITE_TRANSIENT : SQLITE_STATIC);
         else
             rc = sqlite3_bind_zeroblob64(stmt(), idx, value.size);
         return check_bind(rc, idx);
@@ -318,7 +318,7 @@ namespace sqnice {
         return rc;
     }
 
-    
+
 #pragma mark - QUERY:
 
 
@@ -398,6 +398,14 @@ namespace sqnice {
         return sqlite3_column_blob(stmt_, idx_);
     }
 
+    template<> span<const std::byte> column_value::get() const noexcept {
+        // It's important to make the calls in this order,
+        // so we get the size of the blob value, not the string value.
+        auto data = sqlite3_column_blob(stmt_, idx_);
+        auto size = sqlite3_column_bytes(stmt_, idx_);
+        return {(const byte*)data, size_t(size)};
+    }
+
     template<> blob column_value::get() const noexcept {
         // It's important to make the calls in this order,
         // so we get the size of the blob value, not the string value.