add possibility of calculating how many rows there were before LIMIT was applied

The Finder has get_rows_counter() method which returns how many rows there were
before LIMIT clause was applied. The select(...) method should be called with
Select::with_rows_counter flag in such a case.

while here:
- change the semantic of Finder, now the select(...) method takes a morm::Select flags,
  and we have such flags:
  - Select::no_auto_generated_columns - do not generate columns from models
  - with_rows_counter - add an additional column for the rows counter
- remove Finder::prepare_to_select() - now use select(...) with no_auto_generated_columns flag

src/select.h

@@ -0,0 +1,124 @@
+/*
+ * This file is a part of morm
+ * and is distributed under the 2-Clause BSD licence.
+ * Author: Tomasz Sowa <t.sowa@ttmath.org>
+ */
+
+/*
+ * Copyright (c) 2022, Tomasz Sowa
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef headerfile_morm_src_select
+#define headerfile_morm_src_select
+
+namespace morm
+{
+
+/*
+ * additional arguments for Finder::select method
+ */
+class Select
+{
+public:
+
+	enum SelectType
+	{
+		default_type = 0,
+		no_auto_generated_columns = 1,
+		with_rows_counter = 2,
+	};
+
+
+	/*
+	 * type can be a superposition from SelectType values
+	 */
+	int type;
+
+
+
+	Select()
+	{
+		type = 0;
+	}
+
+	Select(const Select & select_type)
+	{
+		this->type = select_type.type;
+	}
+
+	Select(SelectType select_type)
+	{
+		this->type = static_cast<int>(select_type);
+	}
+
+	Select(int type)
+	{
+		this->type = type;
+	}
+
+	Select & operator=(const Select & select_type)
+	{
+		type = select_type.type;
+		return *this;
+	}
+
+	Select & operator=(SelectType select_type)
+	{
+		this->type = static_cast<int>(select_type);
+		return *this;
+	}
+
+	Select & operator=(int type)
+	{
+		this->type = type;
+		return *this;
+	}
+
+
+	bool is_flag_set(int flag_mask) const
+	{
+		return (type & flag_mask) != 0;
+	}
+
+
+	bool is_with_rows_counter() const
+	{
+		return is_flag_set(with_rows_counter);
+	}
+
+
+	bool is_no_auto_generated_columns() const
+	{
+		return is_flag_set(no_auto_generated_columns);
+	}
+
+
+};
+
+}
+
+#endif