# - Try to find Eigen3 lib

#

# This module supports requiring a minimum version, e.g. you can do

#   find_package(Eigen3 3.1.2)

# to require version 3.1.2 or newer of Eigen3.

#

# Once done this will define

#

#  EIGEN3_FOUND - system has eigen lib with correct version

#  EIGEN3_INCLUDE_DIR - the eigen include directory

#  EIGEN3_VERSION - eigen version

# Copyright (c) 2006, 2007 Montel Laurent, <montel@kde.org>

# Copyright (c) 2008, 2009 Gael Guennebaud, <g.gael@free.fr>

# Copyright (c) 2009 Benoit Jacob <jacob.benoit.1@gmail.com>

# Redistribution and use is allowed according to the terms of the 2-clause BSD license.

if(NOT Eigen3_FIND_VERSION)

  if(NOT Eigen3_FIND_VERSION_MAJOR)

    set(Eigen3_FIND_VERSION_MAJOR 2)

  endif(NOT Eigen3_FIND_VERSION_MAJOR)

  if(NOT Eigen3_FIND_VERSION_MINOR)

    set(Eigen3_FIND_VERSION_MINOR 91)

  endif(NOT Eigen3_FIND_VERSION_MINOR)

  if(NOT Eigen3_FIND_VERSION_PATCH)

    set(Eigen3_FIND_VERSION_PATCH 0)

  endif(NOT Eigen3_FIND_VERSION_PATCH)

  set(Eigen3_FIND_VERSION "${Eigen3_FIND_VERSION_MAJOR}.${Eigen3_FIND_VERSION_MINOR}.${Eigen3_FIND_VERSION_PATCH}")

endif(NOT Eigen3_FIND_VERSION)

macro(_eigen3_check_version)

  file(READ "${EIGEN3_INCLUDE_DIR}/Eigen/src/Core/util/Macros.h" _eigen3_version_header)

  string(REGEX MATCH "define[ \t]+EIGEN_WORLD_VERSION[ \t]+([0-9]+)" _eigen3_world_version_match "${_eigen3_version_header}")

  set(EIGEN3_WORLD_VERSION "${CMAKE_MATCH_1}")

  string(REGEX MATCH "define[ \t]+EIGEN_MAJOR_VERSION[ \t]+([0-9]+)" _eigen3_major_version_match "${_eigen3_version_header}")

  set(EIGEN3_MAJOR_VERSION "${CMAKE_MATCH_1}")

  string(REGEX MATCH "define[ \t]+EIGEN_MINOR_VERSION[ \t]+([0-9]+)" _eigen3_minor_version_match "${_eigen3_version_header}")

  set(EIGEN3_MINOR_VERSION "${CMAKE_MATCH_1}")

  set(EIGEN3_VERSION ${EIGEN3_WORLD_VERSION}.${EIGEN3_MAJOR_VERSION}.${EIGEN3_MINOR_VERSION})

  if(${EIGEN3_VERSION} VERSION_LESS ${Eigen3_FIND_VERSION})

    set(EIGEN3_VERSION_OK FALSE)

  else(${EIGEN3_VERSION} VERSION_LESS ${Eigen3_FIND_VERSION})

    set(EIGEN3_VERSION_OK TRUE)

  endif(${EIGEN3_VERSION} VERSION_LESS ${Eigen3_FIND_VERSION})

  if(NOT EIGEN3_VERSION_OK)

    message(STATUS "Eigen3 version ${EIGEN3_VERSION} found in ${EIGEN3_INCLUDE_DIR}, "

                   "but at least version ${Eigen3_FIND_VERSION} is required")

  endif(NOT EIGEN3_VERSION_OK)

endmacro(_eigen3_check_version)

if (EIGEN3_INCLUDE_DIR)

  # in cache already

  _eigen3_check_version()

  set(EIGEN3_FOUND ${EIGEN3_VERSION_OK})

else (EIGEN3_INCLUDE_DIR)

  find_path(EIGEN3_INCLUDE_DIR NAMES signature_of_eigen3_matrix_library

      PATHS

      ${CMAKE_INSTALL_PREFIX}/include

      ${KDE4_INCLUDE_DIR}

      PATH_SUFFIXES eigen3 eigen

    )

  if(EIGEN3_INCLUDE_DIR)

    _eigen3_check_version()

  endif(EIGEN3_INCLUDE_DIR)

  include(FindPackageHandleStandardArgs)

  find_package_handle_standard_args(Eigen3 DEFAULT_MSG EIGEN3_INCLUDE_DIR EIGEN3_VERSION_OK)

  mark_as_advanced(EIGEN3_INCLUDE_DIR)

endif(EIGEN3_INCLUDE_DIR)