# Ceres Solver - A fast non-linear least squares minimizer

# Copyright 2015 Google Inc. All rights reserved.

# http://ceres-solver.org/

#

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#

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# Author: alexs.mac@gmail.com (Alex Stewart)

#

# FindUnorderedMap.cmake - Find unordered_map header and namespace.

#

# This module defines the following variables:

#

# UNORDERED_MAP_FOUND: TRUE if unordered_map is found.

# HAVE_UNORDERED_MAP_IN_STD_NAMESPACE: Use <unordered_map> & std.

# HAVE_UNORDERED_MAP_IN_TR1_NAMESPACE: Use <unordered_map> & std::tr1.

# HAVE_TR1_UNORDERED_MAP_IN_TR1_NAMESPACE: <tr1/unordered_map> & std::tr1.

macro(FIND_UNORDERED_MAP)

  # To support CXX11 option, clear the results of all check_xxx() functions

  # s/t we always perform the checks each time, otherwise CMake fails to

  # detect that the tests should be performed again after CXX11 is toggled.

  unset(HAVE_STD_UNORDERED_MAP_HEADER CACHE)

  unset(HAVE_UNORDERED_MAP_IN_STD_NAMESPACE CACHE)

  unset(HAVE_UNORDERED_MAP_IN_TR1_NAMESPACE CACHE)

  unset(HAVE_TR1_UNORDERED_MAP_IN_TR1_NAMESPACE CACHE)

  set(UNORDERED_MAP_FOUND FALSE)

  include(CheckIncludeFileCXX)

  check_include_file_cxx(unordered_map HAVE_STD_UNORDERED_MAP_HEADER)

  if (HAVE_STD_UNORDERED_MAP_HEADER)

    # Finding the unordered_map header doesn't mean that unordered_map

    # is in std namespace.

    #

    # In particular, MSVC 2008 has unordered_map declared in std::tr1.

    # In order to support this, we do an extra check to see which

    # namespace should be used.

    include(CheckCXXSourceCompiles)

    check_cxx_source_compiles("#include <unordered_map>

                               int main() {

                                 std::unordered_map<int, int> map;

                                 return 0;

                               }"

                               HAVE_UNORDERED_MAP_IN_STD_NAMESPACE)

    if (HAVE_UNORDERED_MAP_IN_STD_NAMESPACE)

      set(UNORDERED_MAP_FOUND TRUE)

      message("-- Found unordered_map/set in std namespace.")

    else (HAVE_UNORDERED_MAP_IN_STD_NAMESPACE)

      check_cxx_source_compiles("#include <unordered_map>

                                 int main() {

                                   std::tr1::unordered_map<int, int> map;

                                   return 0;

                                 }"

                                 HAVE_UNORDERED_MAP_IN_TR1_NAMESPACE)

      if (HAVE_UNORDERED_MAP_IN_TR1_NAMESPACE)

        set(UNORDERED_MAP_FOUND TRUE)

        message("-- Found unordered_map/set in std::tr1 namespace.")

      else (HAVE_UNORDERED_MAP_IN_TR1_NAMESPACE)

        message("-- Found <unordered_map> but cannot find either "

          "std::unordered_map or std::tr1::unordered_map.")

      endif (HAVE_UNORDERED_MAP_IN_TR1_NAMESPACE)

    endif (HAVE_UNORDERED_MAP_IN_STD_NAMESPACE)

  else (HAVE_STD_UNORDERED_MAP_HEADER)

    check_include_file_cxx("tr1/unordered_map"

      HAVE_TR1_UNORDERED_MAP_IN_TR1_NAMESPACE)

    if (HAVE_TR1_UNORDERED_MAP_IN_TR1_NAMESPACE)

      set(UNORDERED_MAP_FOUND TRUE)

      message("-- Found tr1/unordered_map/set in std::tr1 namespace.")

    else (HAVE_TR1_UNORDERED_MAP_IN_TR1_NAMESPACE)

      message("-- Unable to find <unordered_map> or <tr1/unordered_map>.")

    endif (HAVE_TR1_UNORDERED_MAP_IN_TR1_NAMESPACE)

  endif (HAVE_STD_UNORDERED_MAP_HEADER)

endmacro(FIND_UNORDERED_MAP)