# This module defines two macros:
# CMAKE_PUSH_CHECK_STATE()
# and
# CMAKE_POP_CHECK_STATE()
# These two macros can be used to save and restore the state of the variables
# CMAKE_REQUIRED_FLAGS, CMAKE_REQUIRED_DEFINITIONS, CMAKE_REQUIRED_LIBRARIES
# and CMAKE_REQUIRED_INCLUDES used by the various Check-files coming with CMake,
# like e.g. check_function_exists() etc.
# The variable contents are pushed on a stack, pushing multiple times is supported.
# This is useful e.g. when executing such tests in a Find-module, where they have to be set,
# but after the Find-module has been executed they should have the same value
# as they had before.
#
# Usage:
#   cmake_push_check_state()
#   set(CMAKE_REQUIRED_DEFINITIONS ${CMAKE_REQUIRED_DEFINITIONS} -DSOME_MORE_DEF)
#   check_function_exists(...)
#   cmake_pop_check_state()

#=============================================================================
# Copyright 2006-2011 Alexander Neundorf, <neundorf@kde.org>
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# 
# * Redistributions of source code must retain the above copyright
#   notice, this list of conditions and the following disclaimer.
# 
# * Redistributions in binary form must reproduce the above copyright
#   notice, this list of conditions and the following disclaimer in the
#   documentation and/or other materials provided with the distribution.
# 
# * Neither the names of Kitware, Inc., the Insight Software Consortium,
#   nor the names of their contributors may be used to endorse or promote
#   products derived from this software without specific prior written
#   permission.
# 
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
# HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
# 
# ------------------------------------------------------------------------------
# 
# The above copyright and license notice applies to distributions of
# CMake in source and binary form.  Some source files contain additional
# notices of original copyright by their contributors; see each source
# for details.  Third-party software packages supplied with CMake under
# compatible licenses provide their own copyright notices documented in
# corresponding subdirectories.
# 
# ------------------------------------------------------------------------------
# 
# CMake was initially developed by Kitware with the following sponsorship:
# 
#  * National Library of Medicine at the National Institutes of Health
#    as part of the Insight Segmentation and Registration Toolkit (ITK).
# 
#  * US National Labs (Los Alamos, Livermore, Sandia) ASC Parallel
#    Visualization Initiative.
# 
#  * National Alliance for Medical Image Computing (NAMIC) is funded by the
#    National Institutes of Health through the NIH Roadmap for Medical Research,
#    Grant U54 EB005149.
# 
#  * Kitware, Inc.

macro(CMAKE_PUSH_CHECK_STATE)

   if(NOT DEFINED _CMAKE_PUSH_CHECK_STATE_COUNTER)
      set(_CMAKE_PUSH_CHECK_STATE_COUNTER 0)
   endif()

   math(EXPR _CMAKE_PUSH_CHECK_STATE_COUNTER "${_CMAKE_PUSH_CHECK_STATE_COUNTER}+1")

   set(_CMAKE_REQUIRED_INCLUDES_SAVE_${_CMAKE_PUSH_CHECK_STATE_COUNTER}    ${CMAKE_REQUIRED_INCLUDES})
   set(_CMAKE_REQUIRED_DEFINITIONS_SAVE_${_CMAKE_PUSH_CHECK_STATE_COUNTER} ${CMAKE_REQUIRED_DEFINITIONS})
   set(_CMAKE_REQUIRED_LIBRARIES_SAVE_${_CMAKE_PUSH_CHECK_STATE_COUNTER}   ${CMAKE_REQUIRED_LIBRARIES})
   set(_CMAKE_REQUIRED_FLAGS_SAVE_${_CMAKE_PUSH_CHECK_STATE_COUNTER}       ${CMAKE_REQUIRED_FLAGS})
endmacro()

macro(CMAKE_POP_CHECK_STATE)

# don't pop more than we pushed
   if("${_CMAKE_PUSH_CHECK_STATE_COUNTER}" GREATER "0")

      set(CMAKE_REQUIRED_INCLUDES    ${_CMAKE_REQUIRED_INCLUDES_SAVE_${_CMAKE_PUSH_CHECK_STATE_COUNTER}})
      set(CMAKE_REQUIRED_DEFINITIONS ${_CMAKE_REQUIRED_DEFINITIONS_SAVE_${_CMAKE_PUSH_CHECK_STATE_COUNTER}})
      set(CMAKE_REQUIRED_LIBRARIES   ${_CMAKE_REQUIRED_LIBRARIES_SAVE_${_CMAKE_PUSH_CHECK_STATE_COUNTER}})
      set(CMAKE_REQUIRED_FLAGS       ${_CMAKE_REQUIRED_FLAGS_SAVE_${_CMAKE_PUSH_CHECK_STATE_COUNTER}})

      math(EXPR _CMAKE_PUSH_CHECK_STATE_COUNTER "${_CMAKE_PUSH_CHECK_STATE_COUNTER}-1")
   endif()

endmacro()