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------------------------------------------------------------------------------
-- --
-- GNAT COMPILER COMPONENTS --
-- --
-- K R U N C H --
-- --
-- S p e c --
-- --
-- Copyright (C) 1992-2009, Free Software Foundation, Inc. --
-- --
-- GNAT is free software; you can redistribute it and/or modify it under --
-- terms of the GNU General Public License as published by the Free Soft- --
-- ware Foundation; either version 3, or (at your option) any later ver- --
-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
-- or FITNESS FOR A PARTICULAR PURPOSE. --
-- --
-- As a special exception under Section 7 of GPL version 3, you are granted --
-- additional permissions described in the GCC Runtime Library Exception, --
-- version 3.1, as published by the Free Software Foundation. --
-- --
-- You should have received a copy of the GNU General Public License and --
-- a copy of the GCC Runtime Library Exception along with this program; --
-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
-- <http://www.gnu.org/licenses/>. --
-- --
-- GNAT was originally developed by the GNAT team at New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc. --
-- --
------------------------------------------------------------------------------
-- This procedure implements file name crunching
-- First, the name is divided into segments separated by minus signs and
-- underscores, then all minus signs and underscores are eliminated. If
-- this leaves the name short enough, we are done.
-- If not, then the longest segment is located (left-most if there are
-- two of equal length), and shortened by dropping its last character.
-- This is repeated until the name is short enough.
-- As an example, consider the krunch of our-strings-wide_fixed.adb
-- to fit the name into 8 characters as required by DOS:
-- our-strings-wide_fixed 22
-- our strings wide fixed 19
-- our string wide fixed 18
-- our strin wide fixed 17
-- our stri wide fixed 16
-- our stri wide fixe 15
-- our str wide fixe 14
-- our str wid fixe 13
-- our str wid fix 12
-- ou str wid fix 11
-- ou st wid fix 10
-- ou st wi fix 9
-- ou st wi fi 8
-- Final file name: OUSTWIFX.ADB
-- A special rule applies for children of System, Ada, Gnat, and Interfaces.
-- In these cases, the following special prefix replacements occur:
-- ada- replaced by a-
-- gnat- replaced by g-
-- interfaces- replaced by i-
-- system- replaced by s-
-- The rest of the name is krunched in the usual manner described above.
-- In addition, these names, as well as the names of the renamed packages
-- from the obsolescent features annex, are always krunched to 8 characters
-- regardless of the setting of Maxlen.
-- As an example of this special rule, consider ada-strings-wide_fixed.adb
-- which gets krunched as follows:
-- ada-strings-wide_fixed 22
-- a- strings wide fixed 18
-- a- string wide fixed 17
-- a- strin wide fixed 16
-- a- stri wide fixed 15
-- a- stri wide fixe 14
-- a- str wide fixe 13
-- a- str wid fixe 12
-- a- str wid fix 11
-- a- st wid fix 10
-- a- st wi fix 9
-- a- st wi fi 8
-- Final file name: A-STWIFX.ADB
-- Since children of units named A, G, I or S might conflict with the names
-- of predefined units, the naming rule in that case is that the first hyphen
-- is replaced by a tilde sign.
-- Note: as described below, this special treatment of predefined library
-- unit file names can be inhibited by setting the No_Predef flag.
-- Of course there is no guarantee that this algorithm results in uniquely
-- crunched names (nor, obviously, is there any algorithm which would do so)
-- In fact we run into such a case in the standard library routines with
-- children of Wide_Text_IO, so a special rule is applied to deal with this
-- clash, namely the prefix ada-wide_text_io- is replaced by a-wt- and then
-- the normal crunching rules are applied, so that for example, the unit:
-- Ada.Wide_Text_IO.Float_IO
-- has the file name
-- a-wtflio
-- More problems arise with Wide_Wide, so we replace this sequence by
-- a z (which is not used much) and also (as in the Wide_Text_IO case),
-- we replace the prefix ada.wide_wide_text_io- by a-zt- and then
-- the normal crunching rules are applied.
-- These are the only irregularity required (so far!) to keep the file names
-- unique in the standard predefined libraries.
procedure Krunch
(Buffer : in out String;
Len : in out Natural;
Maxlen : Natural;
No_Predef : Boolean;
VMS_On_Target : Boolean := False);
pragma Elaborate_Body (Krunch);
-- The full file name is stored in Buffer (1 .. Len) on entry. The file
-- name is crunched in place and on return Len is updated, so that the
-- resulting krunched name is in Buffer (1 .. Len) where Len <= Maxlen.
-- Note that Len may be less than or equal to Maxlen on entry, in which
-- case it may be possible that Krunch does not modify Buffer. The fourth
-- parameter, No_Predef, is a switch which, if set to True, disables the
-- normal special treatment of predefined library unit file names.
-- VMS_On_Target, when True, indicates to Krunch to apply the VMS treatment
-- to the children of package A, G,I or S.
--
-- Note: the string Buffer must have a lower bound of 1, and may not
-- contain any blanks (in particular, it must not have leading blanks).