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

# Copyright 2015 Google Inc. All rights reserved.

# http://ceres-solver.org/

#

# Redistribution and use in source and binary forms, with or without

# modification, are permitted provided that the following conditions are met:

#

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#   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.

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#   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

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#

# Author: sergey.vfx@gmail.com (Sergey Sharybin)

#

# FindSharedPtr.cmake - Find shared pointer header and namespace.

#

# This module defines the following variables:

#

# SHARED_PTR_FOUND: TRUE if shared_ptr found.

# SHARED_PTR_TR1_MEMORY_HEADER: True if <tr1/memory> header is to be used

# for the shared_ptr object, otherwise use <memory>.

# SHARED_PTR_TR1_NAMESPACE: TRUE if shared_ptr is defined in std::tr1 namespace,

# otherwise it's assumed to be defined in std namespace.

macro(FIND_SHARED_PTR)

  # 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_MEMORY_HEADER CACHE)

  unset(HAVE_SHARED_PTR_IN_STD_NAMESPACE CACHE)

  unset(HAVE_SHARED_PTR_IN_TR1_NAMESPACE CACHE)

  unset(HAVE_TR1_MEMORY_HEADER CACHE)

  unset(HAVE_SHARED_PTR_IN_TR1_NAMESPACE_FROM_TR1_MEMORY_HEADER CACHE)

  set(SHARED_PTR_FOUND FALSE)

  check_include_file_cxx(memory HAVE_STD_MEMORY_HEADER)

  if (HAVE_STD_MEMORY_HEADER)

    # Finding the memory header doesn't mean that shared_ptr is in std

    # namespace.

    #

    # In particular, MSVC 2008 has shared_ptr 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 <memory>

                               int main() {

                                 std::shared_ptr<int> int_ptr;

                                 return 0;

                               }"

                              HAVE_SHARED_PTR_IN_STD_NAMESPACE)

    if (HAVE_SHARED_PTR_IN_STD_NAMESPACE)

      message("-- Found shared_ptr in std namespace using <memory> header.")

      set(SHARED_PTR_FOUND TRUE)

    else (HAVE_SHARED_PTR_IN_STD_NAMESPACE)

      check_cxx_source_compiles("#include <memory>

                                 int main() {

                                   std::tr1::shared_ptr<int> int_ptr;

                                   return 0;

                                 }"

                                HAVE_SHARED_PTR_IN_TR1_NAMESPACE)

      if (HAVE_SHARED_PTR_IN_TR1_NAMESPACE)

        message("-- Found shared_ptr in std::tr1 namespace using <memory> header.")

        set(SHARED_PTR_TR1_NAMESPACE TRUE)

        set(SHARED_PTR_FOUND TRUE)

      endif (HAVE_SHARED_PTR_IN_TR1_NAMESPACE)

    endif (HAVE_SHARED_PTR_IN_STD_NAMESPACE)

  endif (HAVE_STD_MEMORY_HEADER)

  if (NOT SHARED_PTR_FOUND)

    # Further, gcc defines shared_ptr in std::tr1 namespace and

    # <tr1/memory> is to be included for this. And what makes things

    # even more tricky is that gcc does have <memory> header, so

    # all the checks above wouldn't find shared_ptr.

    check_include_file_cxx("tr1/memory" HAVE_TR1_MEMORY_HEADER)

    if (HAVE_TR1_MEMORY_HEADER)

      check_cxx_source_compiles("#include <tr1/memory>

                                 int main() {

                                   std::tr1::shared_ptr<int> int_ptr;

                                   return 0;

                                 }"

                                HAVE_SHARED_PTR_IN_TR1_NAMESPACE_FROM_TR1_MEMORY_HEADER)

      if (HAVE_SHARED_PTR_IN_TR1_NAMESPACE_FROM_TR1_MEMORY_HEADER)

        message("-- Found shared_ptr in std::tr1 namespace using <tr1/memory> header.")

          set(SHARED_PTR_TR1_MEMORY_HEADER TRUE)

          set(SHARED_PTR_TR1_NAMESPACE TRUE)

        set(SHARED_PTR_FOUND TRUE)

      endif (HAVE_SHARED_PTR_IN_TR1_NAMESPACE_FROM_TR1_MEMORY_HEADER)

    endif (HAVE_TR1_MEMORY_HEADER)

  endif (NOT SHARED_PTR_FOUND)

endmacro(FIND_SHARED_PTR)