Ada Programming/Libraries/Ada.Sequential IO

Ada.Sequential_IO __TOC__ Ada Sequential_IO is a unit of the Predefined Language Environment since Ada 95. Background Not all data read or written is in text format. For storage or inter-process communication, it is more space- and processing time-efficient to store data in binary format. Binary input and output for sequential data (that is, read/written one after another) is managed by the generic Ada package Ada.Sequential_IO. The generic package must be instantiated with some Element_Type, and provides a limited private File_Type. The file mode, In_File or Out_File, is established on open or create. The package provides the basic input/output (I/O) operations: Open, Create Close, Delete, and Reset Read, Write In addition, the package provides status and information functions: Is_Open End_Of_File Name, Mode, and Form One important restriction is that every element of a file must be the same element type. Ada Code Example For example, suppose that a student has collected information on trees in a 10 meter by 10 meter plot, and wishes a report generated from the data. The following is a simple program to read the sequential data, previously recorded: with Ada Text_IO; Text I/O library with Ada Float_Text_IO; Float I/O library with Ada Sequential_IO; Sequential I/O library procedure Tree_Report is First, define the contents of the data record type Tree_Record is record Common_Name : String(1double_dot ..20) := (others arrow => ' '); Scientific_Name : String(1double_dot ..20) := (others arrow => ' '); Diameter : Float := 0dot .0; at breast height (DBH) end record; Tree_Record Now, instantiate the I/O package for the data record package Tree_IO is new Adadot .Sequential_IO(Tree_Record); Tree_File : Tree_IOdot .File_Type; Input data file Tree_Data : Tree_Record; Individual data record begin Tree_Report Open the input data file. Tree_IOdot .Open(File arrow => Tree_File, Mode arrow => Tree_IOdot .In_File, Name arrow => "tree.dat"); Write report heading Adadot .Text_IOdot .Set_Col(To arrow => 1); Adadot .Text_IOdot .Put("COMMON NAME"); Adadot .Text_IOdot .Set_Col(To arrow => 21); Adadot .Text_IOdot .Put("SCIENTIFIC NAME"); Adadot .Text_IOdot .Set_Col(To arrow => 41); Adadot .Text_IOdot .Put("DBH"); Adadot .Text_IOdot .New_Line; Process_Tree_Data: while not Tree_IOdot .End_Of_File(Tree_File) loop Tree_IOdot .Read(Tree_File, Tree_Data); Read tree data Write tree inventory Adadot .Text_IOdot .Put(Tree_Datadot .Common_Name); Adadot .Text_IOdot .Put(Tree_Datadot .Scientific_Name); Adadot .Float_Text_IOdot .Put(Tree_Datadot .Diameter,Forearrow =>2,Aftarrow =>2,Exparrow =>0); Adadot .Text_IOdot .New_Line; end loop Process_Tree_Data; All data records have been read, and end_of_file detected. Tree_IOdot .Close(Tree_File); Done, close file end Tree_Report; Specification Standard Ada library specification Copyright (c) 2003-2018 Maxim Reznik <reznikmm@gmail.com> Copyright (c) 2004-2016 AXE Consultants Copyright (c) 2004, 2005, 2006 Ada-Europe Copyright (c) 2000 The MITRE Corporation, Inc. Copyright (c) 1992, 1993, 1994, 1995 Intermetrics, Inc. SPDX-License-Identifier: BSD-3-Clause and LicenseRef-AdaReferenceManual ------------------------------------------------------------------------- with Ada IO_Exceptions; generic type Element_Type (box <>) is private; package Ada Sequential_IO is type File_Type is limited private; type File_Mode is (In_File, Out_File, Append_File); File management procedure Create (File : in out File_Type; Mode : in File_Mode := Out_File; Name : in String := ""; Form : in String := ""); procedure Open (File : in out File_Type; Mode : in File_Mode; Name : in String; Form : in String := ""); procedure Close (File : in out File_Type); procedure Delete (File : in out File_Type); procedure Reset (File : in out File_Type; Mode : in File_Mode); procedure Reset (File : in out File_Type); function Mode (File : in File_Type) return File_Mode; function Name (File : in File_Type) return String; function Form (File : in File_Type) return String; function Is_Open (File : in File_Type) return Boolean; Input and output operations procedure Read (File : in File_Type; Item : out Element_Type); procedure Write (File : in File_Type; Item : in Element_Type); function End_Of_File (File : in File_Type) return Boolean; Exceptions Status_Error : exception renames IO_Exceptionsdot .Status_Error; Mode_Error : exception renames IO_Exceptionsdot .Mode_Error; Name_Error : exception renames IO_Exceptionsdot .Name_Error; Use_Error : exception renames IO_Exceptionsdot .Use_Error; Device_Error : exception renames IO_Exceptionsdot .Device_Error; End_Error : exception renames IO_Exceptionsdot .End_Error; Data_Error : exception renames IO_Exceptionsdot .Data_Error; private type File_Type is limited null record; end Adadot .Sequential_IO; See also Wikibook Ada Programming/Libraries/Ada Ada Reference Manual Ada 95 A 8 1 The Generic Package Sequential_IO Ada 2005 A 8 1 The Generic Package Sequential_IO Ada 2012 A 8 1 The Generic Package Sequential_IO Open-Source Implementations a-sequio.ads a-sequio.adb streams/a-sequio.ads streams/a-sequio.adb