From 656fb6602f722290b3a4a935468d5a3662563b3c Mon Sep 17 00:00:00 2001
From: Mikhail Komarov <nemo@nil.foundation>
Date: Sat, 10 Aug 2019 09:29:18 +0300
Subject: [PATCH] Missing Eigen3 lookup CMake module implemented [ci skip]

---
 cmake/packages/FindEigen3.cmake | 91 +++++++++++++++++++++++++++++++++
 1 file changed, 91 insertions(+)
 create mode 100644 cmake/packages/FindEigen3.cmake

diff --git a/cmake/packages/FindEigen3.cmake b/cmake/packages/FindEigen3.cmake
new file mode 100644
index 000000000..08fcb9daa
--- /dev/null
+++ b/cmake/packages/FindEigen3.cmake
@@ -0,0 +1,91 @@
+#---------------------------------------------------------------------------#
+# Copyright (c) 2018-2019 Nil Foundation AG
+# Copyright (c) 2018-2019 Mikhail Komarov <nemo@nil.foundation>
+#
+# Distributed under the Boost Software License, Version 1.0
+# See accompanying file LICENSE_1_0.txt or copy at
+# http://www.boost.org/LICENSE_1_0.txt
+#---------------------------------------------------------------------------#
+
+# Try to find Eigen3 library
+# http://eigen.tuxfamily.org
+#
+# 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
+
+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)
+
+    # specific additional paths for some OS
+    if(WIN32)
+        set(EIGEN_ADDITIONAL_SEARCH_PATHS ${EIGEN_ADDITIONAL_SEARCH_PATHS} "C:/Program Files/Eigen/include" "C:/Program Files (x86)/Eigen/include")
+    endif(WIN32)
+
+    find_path(EIGEN3_INCLUDE_DIR NAMES signature_of_eigen3_matrix_library
+              PATHS
+              include
+              ${EIGEN_ADDITIONAL_SEARCH_PATHS}
+              ${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)
\ No newline at end of file