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# ===========================================================================
# https://www.gnu.org/software/autoconf-archive/ax_normalize_path.html
# ===========================================================================
#
# SYNOPSIS
#
# AX_NORMALIZE_PATH(VARNAME, [REFERENCE_STRING])
#
# DESCRIPTION
#
# Perform some cleanups on the value of $VARNAME (interpreted as a path):
#
# - empty paths are changed to '.'
# - trailing slashes are removed
# - repeated slashes are squeezed except a leading doubled slash '//'
# (which might indicate a networked disk on some OS).
#
# REFERENCE_STRING is used to turn '/' into '\' and vice-versa: if
# REFERENCE_STRING contains some backslashes, all slashes and backslashes
# are turned into backslashes, otherwise they are all turned into slashes.
#
# This makes processing of DOS filenames quite easier, because you can
# turn a filename to the Unix notation, make your processing, and turn it
# back to original notation.
#
# filename='A:\FOO\\BAR\'
# old_filename="$filename"
# # Switch to the unix notation
# AX_NORMALIZE_PATH([filename], ["/"])
# # now we have $filename = 'A:/FOO/BAR' and we can process it as if
# # it was a Unix path. For instance let's say that you want
# # to append '/subpath':
# filename="$filename/subpath"
# # finally switch back to the original notation
# AX_NORMALIZE_PATH([filename], ["$old_filename"])
# # now $filename equals to 'A:\FOO\BAR\subpath'
#
# One good reason to make all path processing with the unix convention is
# that backslashes have a special meaning in many cases. For instance
#
# expr 'A:\FOO' : 'A:\Foo'
#
# will return 0 because the second argument is a regex in which
# backslashes have to be backslashed. In other words, to have the two
# strings to match you should write this instead:
#
# expr 'A:\Foo' : 'A:\\Foo'
#
# Such behavior makes DOS filenames extremely unpleasant to work with. So
# temporary turn your paths to the Unix notation, and revert them to the
# original notation after the processing. See the macro
# AX_COMPUTE_RELATIVE_PATHS for a concrete example of this.
#
# REFERENCE_STRING defaults to $VARIABLE, this means that slashes will be
# converted to backslashes if $VARIABLE already contains some backslashes
# (see $thirddir below).
#
# firstdir='/usr/local//share'
# seconddir='C:\Program Files\\'
# thirddir='C:\home/usr/'
# AX_NORMALIZE_PATH([firstdir])
# AX_NORMALIZE_PATH([seconddir])
# AX_NORMALIZE_PATH([thirddir])
# # $firstdir = '/usr/local/share'
# # $seconddir = 'C:\Program Files'
# # $thirddir = 'C:\home\usr'
#
# LICENSE
#
# Copyright (c) 2008 Alexandre Duret-Lutz <adl@gnu.org>
#
# This program is free software; you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by the
# Free Software Foundation; either version 2 of the License, or (at your
# option) any later version.
#
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
# Public License for more details.
#
# You should have received a copy of the GNU General Public License along
# with this program. If not, see <https://www.gnu.org/licenses/>.
#
# As a special exception, the respective Autoconf Macro's copyright owner
# gives unlimited permission to copy, distribute and modify the configure
# scripts that are the output of Autoconf when processing the Macro. You
# need not follow the terms of the GNU General Public License when using
# or distributing such scripts, even though portions of the text of the
# Macro appear in them. The GNU General Public License (GPL) does govern
# all other use of the material that constitutes the Autoconf Macro.
#
# This special exception to the GPL applies to versions of the Autoconf
# Macro released by the Autoconf Archive. When you make and distribute a
# modified version of the Autoconf Macro, you may extend this special
# exception to the GPL to apply to your modified version as well.
#serial 8
AU_ALIAS([ADL_NORMALIZE_PATH], [AX_NORMALIZE_PATH])
AC_DEFUN([AX_NORMALIZE_PATH],
[case ":[$]$1:" in
# change empty paths to '.'
::) $1='.' ;;
# strip trailing slashes
:*[[\\/]]:) $1=`echo "[$]$1" | sed 's,[[\\/]]*[$],,'` ;;
:*:) ;;
esac
# squeeze repeated slashes
case ifelse($2,,"[$]$1",$2) in
# if the path contains any backslashes, turn slashes into backslashes
*\\*) $1=`echo "[$]$1" | sed 's,\(.\)[[\\/]][[\\/]]*,\1\\\\,g'` ;;
# if the path contains slashes, also turn backslashes into slashes
*) $1=`echo "[$]$1" | sed 's,\(.\)[[\\/]][[\\/]]*,\1/,g'` ;;
esac])