256 lines
12 KiB
Ada
256 lines
12 KiB
Ada
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------------------------------------------------------------------------------
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-- --
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-- GNAT RUN-TIME COMPONENTS --
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-- --
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-- S Y S T E M . F I L E _ I O --
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-- --
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-- S p e c --
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-- --
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-- Copyright (C) 1992-2012, Free Software Foundation, Inc. --
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-- --
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-- GNAT is free software; you can redistribute it and/or modify it under --
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-- terms of the GNU General Public License as published by the Free Soft- --
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-- ware Foundation; either version 3, or (at your option) any later ver- --
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-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
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-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
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-- or FITNESS FOR A PARTICULAR PURPOSE. --
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-- --
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-- As a special exception under Section 7 of GPL version 3, you are granted --
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-- additional permissions described in the GCC Runtime Library Exception, --
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-- version 3.1, as published by the Free Software Foundation. --
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-- --
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-- You should have received a copy of the GNU General Public License and --
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-- a copy of the GCC Runtime Library Exception along with this program; --
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-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
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-- <http://www.gnu.org/licenses/>. --
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-- --
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-- GNAT was originally developed by the GNAT team at New York University. --
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-- Extensive contributions were provided by Ada Core Technologies Inc. --
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-- --
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------------------------------------------------------------------------------
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-- This package provides support for the routines described in (RM A.8.2)
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-- which are common to Text_IO, Direct_IO, Sequential_IO and Stream_IO.
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with Interfaces.C_Streams;
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with System.File_Control_Block;
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package System.File_IO is
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pragma Preelaborate;
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package FCB renames System.File_Control_Block;
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package ICS renames Interfaces.C_Streams;
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---------------------
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-- File Management --
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---------------------
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procedure Open
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(File_Ptr : in out FCB.AFCB_Ptr;
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Dummy_FCB : FCB.AFCB'Class;
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Mode : FCB.File_Mode;
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Name : String;
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Form : String;
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Amethod : Character;
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Creat : Boolean;
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Text : Boolean;
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C_Stream : ICS.FILEs := ICS.NULL_Stream);
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-- This routine is used for both Open and Create calls:
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--
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-- File_Ptr is the file type, which must be null on entry
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-- (i.e. the file must be closed before the call).
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--
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-- Dummy_FCB is a default initialized file control block of appropriate
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-- type. Note that the tag of this record indicates the type and length
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-- of the control block. This control block is used only for the purpose
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-- of providing the controlling argument for calling the write version
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-- of Allocate_AFCB. It has no other purpose, and its fields are never
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-- read or written.
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--
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-- Mode is the required mode
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--
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-- Name is the file name, with a null string indicating that a temporary
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-- file is to be created (only permitted in create mode, not open mode).
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--
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-- Creat is True for a create call, and false for an open call
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--
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-- Text is set True to open the file in text mode (w+t or r+t) instead
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-- of the usual binary mode open (w+b or r+b).
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--
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-- Form is the form string given in the open or create call, this is
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-- stored in the AFCB.
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--
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-- Amethod indicates the access method:
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--
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-- D = Direct_IO
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-- Q = Sequential_IO
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-- S = Stream_IO
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-- T = Text_IO
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-- W = Wide_Text_IO
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-- ??? Wide_Wide_Text_IO ???
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--
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-- C_Stream is left at its default value for the normal case of an
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-- Open or Create call as defined in the RM. The only time this is
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-- non-null is for the Open call from Ada.xxx_IO.C_Streams.Open.
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--
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-- On return, if the open/create succeeds, then the fields of File are
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-- filled in, and this value is copied to the heap. File_Ptr points to
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-- this allocated file control block. If the open/create fails, then the
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-- fields of File are undefined, and File_Ptr is unchanged.
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procedure Close (File_Ptr : access FCB.AFCB_Ptr);
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-- The file is closed, all storage associated with it is released, and
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-- File is set to null. Note that this routine calls AFCB_Close to perform
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-- any specialized close actions, then closes the file at the system level,
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-- then frees the mode and form strings, and finally calls AFCB_Free to
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-- free the file control block itself, setting File.all to null. Note that
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-- for this assignment to be done in all cases, including those where
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-- an exception is raised, we can't use an IN OUT parameter (which would
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-- not be copied back in case of abnormal return).
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procedure Delete (File_Ptr : access FCB.AFCB_Ptr);
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-- The indicated file is unlinked
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procedure Reset (File_Ptr : access FCB.AFCB_Ptr; Mode : FCB.File_Mode);
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-- The file is reset, and the mode changed as indicated
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procedure Reset (File_Ptr : access FCB.AFCB_Ptr);
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-- The files is reset, and the mode is unchanged
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function Mode (File : FCB.AFCB_Ptr) return FCB.File_Mode;
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-- Returns the mode as supplied by create, open or reset
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function Name (File : FCB.AFCB_Ptr) return String;
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-- Returns the file name as supplied by Open or Create. Raises Use_Error
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-- if used with temporary files or standard files.
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function Form (File : FCB.AFCB_Ptr) return String;
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-- Returns the form as supplied by create, open or reset The string is
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-- normalized to all lower case letters.
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function Is_Open (File : FCB.AFCB_Ptr) return Boolean;
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-- Determines if file is open or not
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----------------------
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-- Utility Routines --
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----------------------
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-- Some internal routines not defined in A.8.2. These are routines which
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-- provide required common functionality shared by separate packages.
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procedure Chain_File (File : FCB.AFCB_Ptr);
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-- Used to chain the given file into the list of open files. Normally this
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-- is done implicitly by Open. Chain_File is used for the special cases of
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-- the system files defined by Text_IO (stdin, stdout, stderr) which are
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-- not opened in the normal manner. Note that the caller is responsible
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-- for task lock out to protect the global data structures if this is
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-- necessary (it is needed for the calls from within this unit itself,
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-- but not required for the calls from Text_IO and [Wide_]Wide_Text_IO
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-- that are made during elaboration of the environment task).
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procedure Check_File_Open (File : FCB.AFCB_Ptr);
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-- If the current file is not open, then Status_Error is raised. Otherwise
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-- control returns normally (with File pointing to the control block for
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-- the open file.
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procedure Check_Read_Status (File : FCB.AFCB_Ptr);
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-- If the current file is not open, then Status_Error is raised. If the
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-- file is open, then the mode is checked to make sure that reading is
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-- permitted, and if not Mode_Error is raised, otherwise control returns
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-- normally.
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procedure Check_Write_Status (File : FCB.AFCB_Ptr);
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-- If the current file is not open, then Status_Error is raised. If the
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-- file is open, then the mode is checked to ensure that writing is
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-- permitted, and if not Mode_Error is raised, otherwise control returns
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-- normally.
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function End_Of_File (File : FCB.AFCB_Ptr) return Boolean;
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-- File must be opened in read mode. True is returned if the stream is
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-- currently positioned at the end of file, otherwise False is returned.
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-- The position of the stream is not affected.
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procedure Flush (File : FCB.AFCB_Ptr);
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-- Flushes the stream associated with the given file. The file must be open
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-- and in write mode (if not, an appropriate exception is raised)
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function Form_Boolean
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(Form : String;
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Keyword : String;
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Default : Boolean) return Boolean;
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-- Searches form string for an entry of the form keyword=xx where xx is
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-- either yes/no or y/n. Returns True if yes or y is found, False if no or
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-- n is found. If the keyword parameter is not found, returns the value
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-- given as Default. May raise Use_Error if a form string syntax error is
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-- detected. Keyword and Form must be in lower case.
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function Form_Integer
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(Form : String;
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Keyword : String;
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Default : Integer) return Integer;
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-- Searches form string for an entry of the form Keyword=xx where xx is an
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-- unsigned decimal integer in the range 0 to 999_999. Returns this integer
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-- value if it is found. If the keyword parameter is not found, returns the
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-- value given as Default. Raise Use_Error if a form string syntax error is
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-- detected. Keyword and Form must be in lower case.
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procedure Form_Parameter
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(Form : String;
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Keyword : String;
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Start : out Natural;
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Stop : out Natural);
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-- Searches form string for an entry of the form Keyword=xx and if found
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-- Sets Start and Stop to the first and last characters of xx. Keyword
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-- and Form must be in lower case. If no entry matches, then Start and
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-- Stop are set to zero on return. Use_Error is raised if a malformed
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-- string is detected, but there is no guarantee of full syntax checking.
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procedure Read_Buf
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(File : FCB.AFCB_Ptr;
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Buf : Address;
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Siz : Interfaces.C_Streams.size_t);
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-- Reads Siz bytes from File.Stream into Buf. The caller has checked
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-- that the file is open in read mode. Raises an exception if Siz bytes
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-- cannot be read (End_Error if no data was read, Data_Error if a partial
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-- buffer was read, Device_Error if an error occurs).
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procedure Read_Buf
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(File : FCB.AFCB_Ptr;
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Buf : Address;
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Siz : Interfaces.C_Streams.size_t;
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Count : out Interfaces.C_Streams.size_t);
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-- Reads Siz bytes from File.Stream into Buf. The caller has checked that
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-- the file is open in read mode. Device Error is raised if an error
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-- occurs. Count is the actual number of bytes read, which may be less
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-- than Siz if the end of file is encountered.
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procedure Append_Set (File : FCB.AFCB_Ptr);
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-- If the mode of the file is Append_File, then the file is positioned at
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-- the end of file using fseek, otherwise this call has no effect.
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procedure Write_Buf
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(File : FCB.AFCB_Ptr;
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Buf : Address;
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Siz : Interfaces.C_Streams.size_t);
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-- Writes size_t bytes to File.Stream from Buf. The caller has checked that
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-- the file is open in write mode. Raises Device_Error if the complete
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-- buffer cannot be written.
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procedure Make_Unbuffered (File : FCB.AFCB_Ptr);
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procedure Make_Line_Buffered
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(File : FCB.AFCB_Ptr;
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Line_Siz : Interfaces.C_Streams.size_t);
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procedure Make_Buffered
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(File : FCB.AFCB_Ptr;
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Buf_Siz : Interfaces.C_Streams.size_t);
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private
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pragma Inline (Check_Read_Status);
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pragma Inline (Check_Write_Status);
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pragma Inline (Mode);
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end System.File_IO;
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