From e8b1b90920af27542638f14d3bfe4dc5bb64c847 Mon Sep 17 00:00:00 2001
From: Reinhold Gschweicher <rgschweicher@riegl.com>
Date: Tue, 15 Jan 2019 10:14:48 +0100
Subject: [PATCH] hunter: prefer CXSparse from SuiteSparse

Change-Id: I1cfd837d45e1c7edf4c8eaa4feea2c631517efcf
---
 CMakeLists.txt | 51 +++++++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 44 insertions(+), 7 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 48cb10b948..efde031cee 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -310,7 +310,48 @@ else (SUITESPARSE)
 endif (SUITESPARSE)
 
 # CXSparse.
-if (CXSPARSE)
+if (CXSPARSE AND TARGET SuiteSparse::cxsparse)
+  # use suitesparse provided cxsparse target
+  # Extract CXSparse version from cs.h
+  set(CXSPARSE_INCLUDE_DIR "${SuiteSparse_INCLUDE_DIRS}/suitesparse")
+  if (CXSPARSE_INCLUDE_DIR)
+    set(CXSPARSE_VERSION_FILE ${CXSPARSE_INCLUDE_DIR}/cs.h)
+    if (NOT EXISTS ${CXSPARSE_VERSION_FILE})
+      message(
+        "Could not find file: ${CXSPARSE_VERSION_FILE} "
+        "containing version information in CXSparse install located at: "
+        "${CXSPARSE_INCLUDE_DIR}.")
+    else (NOT EXISTS ${CXSPARSE_VERSION_FILE})
+      file(READ ${CXSPARSE_INCLUDE_DIR}/cs.h CXSPARSE_VERSION_FILE_CONTENTS)
+
+      string(REGEX MATCH "#define CS_VER [0-9]+"
+        CXSPARSE_MAIN_VERSION "${CXSPARSE_VERSION_FILE_CONTENTS}")
+      string(REGEX REPLACE "#define CS_VER ([0-9]+)" "\\1"
+        CXSPARSE_MAIN_VERSION "${CXSPARSE_MAIN_VERSION}")
+
+      string(REGEX MATCH "#define CS_SUBVER [0-9]+"
+        CXSPARSE_SUB_VERSION "${CXSPARSE_VERSION_FILE_CONTENTS}")
+      string(REGEX REPLACE "#define CS_SUBVER ([0-9]+)" "\\1"
+        CXSPARSE_SUB_VERSION "${CXSPARSE_SUB_VERSION}")
+
+      string(REGEX MATCH "#define CS_SUBSUB [0-9]+"
+        CXSPARSE_SUBSUB_VERSION "${CXSPARSE_VERSION_FILE_CONTENTS}")
+      string(REGEX REPLACE "#define CS_SUBSUB ([0-9]+)" "\\1"
+        CXSPARSE_SUBSUB_VERSION "${CXSPARSE_SUBSUB_VERSION}")
+
+      # This is on a single line s/t CMake does not interpret it as a list of
+      # elements and insert ';' separators which would result in 3.;1.;2 nonsense.
+      set(CXSPARSE_VERSION "${CXSPARSE_MAIN_VERSION}.${CXSPARSE_SUB_VERSION}.${CXSPARSE_SUBSUB_VERSION}")
+    endif (NOT EXISTS ${CXSPARSE_VERSION_FILE})
+  endif (CXSPARSE_INCLUDE_DIR)
+  if (NOT CXSPARSE_VERSION)
+    set(CXSPARSE_VERSION ${SuiteSparse_VERSION})
+  endif()
+  set(CXSPARSE_LIBRARIES SuiteSparse::cxsparse)
+  set(CXSPARSE_FOUND TRUE)
+  message("-- Using target SuiteSparse::cxsparse with version: ${CXSPARSE_VERSION}, "
+    "building with CXSparse.")
+elseif (CXSPARSE)
   # Don't search with REQUIRED as we can continue without CXSparse.
   find_package(CXSparse)
   if (CXSPARSE_FOUND)
@@ -324,7 +365,7 @@ if (CXSPARSE)
     update_cache_variable(CXSPARSE OFF)
     list(APPEND CERES_COMPILE_OPTIONS CERES_NO_CXSPARSE)
   endif (CXSPARSE_FOUND)
-else (CXSPARSE)
+else ()
   message("-- Building without CXSparse.")
   list(APPEND CERES_COMPILE_OPTIONS CERES_NO_CXSPARSE)
   # Mark as advanced (remove from default GUI view) the CXSparse search
@@ -333,7 +374,7 @@ else (CXSPARSE)
   # CXSPARSE instead of setting them.
   mark_as_advanced(FORCE CXSPARSE_INCLUDE_DIR
                          CXSPARSE_LIBRARY)
-endif (CXSPARSE)
+endif ()
 
 # Ensure that the user understands they have disabled all sparse libraries.
 if (NOT SUITESPARSE AND NOT CXSPARSE AND NOT EIGENSPARSE)
@@ -597,10 +638,6 @@ include_directories(
 # as system headers.
 include_directories(SYSTEM ${EIGEN_INCLUDE_DIRS})
 
-if (CXSPARSE)
-  include_directories(${CXSPARSE_INCLUDE_DIRS})
-endif (CXSPARSE)
-
 if (GFLAGS)
   include_directories(${GFLAGS_INCLUDE_DIRS})
 endif (GFLAGS)