# ===========================================================================
#          http://www.nongnu.org/autoconf-archive/ax_check_zlib.html
# ===========================================================================
#
# SYNOPSIS
#
#   AX_CHECK_ZLIB()
#
# DESCRIPTION
#
#   This macro searches for an installed zlib library. If nothing was
#   specified when calling configure, it searches first in /usr/local and
#   then in /usr. If the --with-zlib=DIR is specified, it will try to find
#   it in DIR/include/zlib.h and DIR/lib/libz.a. If --without-zlib is
#   specified, the library is not searched at all.
#
#   If either the header file (zlib.h) or the library (libz) is not found,
#   the configuration exits on error, asking for a valid zlib installation
#   directory or --without-zlib.
#
#   The macro defines the symbol HAVE_LIBZ if the library is found. You
#   should use autoheader to include a definition for this symbol in a
#   config.h file. Sample usage in a C/C++ source is as follows:
#
#     #ifdef HAVE_LIBZ
#     #include <zlib.h>
#     #endif /* HAVE_LIBZ */
#
# LICENSE
#
#   Copyright (c) 2008 Loic Dachary <loic@senga.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 <http://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.

AU_ALIAS([CHECK_ZLIB], [AX_CHECK_ZLIB])
AC_DEFUN([AX_CHECK_ZLIB],
#
# Handle user hints
#
[AC_MSG_CHECKING(if zlib is wanted)
AC_ARG_WITH(zlib,
[  --with-zlib=DIR root directory path of zlib installation [defaults to
                    /usr/local or /usr if not found in /usr/local]
  --without-zlib to disable zlib usage completely],
[if test "$withval" != no ; then
  AC_MSG_RESULT(yes)
  if test -d "$withval"
  then
    ZLIB_HOME="$withval"
  else
    AC_MSG_WARN([Sorry, $withval does not exist, checking usual places])
  fi
else
  AC_MSG_RESULT(no)
fi])

ZLIB_HOME=/usr/local
if test ! -f "${ZLIB_HOME}/include/zlib.h"
then
        ZLIB_HOME=/usr
fi

#
# Locate zlib, if wanted
#
if test -n "${ZLIB_HOME}"
then
        ZLIB_OLD_LDFLAGS=$LDFLAGS
        ZLIB_OLD_CPPFLAGS=$LDFLAGS
        LDFLAGS="$LDFLAGS -L${ZLIB_HOME}/lib"
        CPPFLAGS="$CPPFLAGS -I${ZLIB_HOME}/include"
        AC_LANG_SAVE
        AC_LANG_C
        AC_CHECK_LIB(z, inflateEnd, [zlib_cv_libz=yes], [zlib_cv_libz=no])
        AC_CHECK_HEADER(zlib.h, [zlib_cv_zlib_h=yes], [zlib_cv_zlib_h=no])
        AC_LANG_RESTORE
        if test "$zlib_cv_libz" = "yes" -a "$zlib_cv_zlib_h" = "yes"
        then
                #
                # If both library and header were found, use them
                #
                AC_CHECK_LIB(z, inflateEnd)
                AC_MSG_CHECKING(zlib in ${ZLIB_HOME})
                AC_MSG_RESULT(ok)
        else
                #
                # If either header or library was not found, revert and bomb
                #
                AC_MSG_CHECKING(zlib in ${ZLIB_HOME})
                LDFLAGS="$ZLIB_OLD_LDFLAGS"
                CPPFLAGS="$ZLIB_OLD_CPPFLAGS"
                AC_MSG_RESULT(failed)
                AC_MSG_ERROR(either specify a valid zlib installation with --with-zlib=DIR or disable zlib usage with --without-zlib)
        fi
fi

])