ENH: GeoTIFF version parsing

CMake/FindGeoTIFF.cmake

@@ -4,11 +4,32 @@
 #   GEOTIFF_FOUND        - True if GEOTIFF found.
 #   GEOTIFF_INCLUDE_DIRS - where to find geotiff.h
 #   GEOTIFF_LIBRARIES    - List of libraries to link when using GEOTIFF.
+#   GEOTIFF_VERSION        - version string
+#   GEOTIFF_VERSION_MAJOR  - version major number
+#   GEOTIFF_VERSION_MINOR  - version minor number
+#   GEOTIFF_VERSION_PATCH  - version patch number
+#   GEOTIFF_VERSION_NUMBER - version number ((major*100)+minor)*100+patch
+
 #
 
 find_path( GEOTIFF_INCLUDE_DIR geotiff.h
            PATH_SUFFIXES geotiff libgeotiff )
 
+if(EXISTS "${GEOTIFF_INCLUDE_DIR}/geotiff.h")
+  file(READ "${GEOTIFF_INCLUDE_DIR}/geotiff.h" _geotiff_h_CONTENTS)
+  string(REGEX REPLACE ".*# *define +LIBGEOTIFF_VERSION +([0-9])([0-9])([0-9])([0-9]).*" "\\1" GEOTIFF_VERSION_MAJOR "${_geotiff_h_CONTENTS}")
+  string(REGEX REPLACE ".*# *define +LIBGEOTIFF_VERSION +([0-9])([0-9])([0-9])([0-9]).*" "\\2" GEOTIFF_VERSION_MINOR "${_geotiff_h_CONTENTS}")
+  string(REGEX REPLACE ".*# *define +LIBGEOTIFF_VERSION +([0-9])([0-9])([0-9])([0-9]).*" "\\3" GEOTIFF_VERSION_PATCH "${_geotiff_h_CONTENTS}")
+  set(GEOTIFF_VERSION "${GEOTIFF_VERSION_MAJOR}.${GEOTIFF_VERSION_MINOR}.${GEOTIFF_VERSION_PATCH}")
+  math(EXPR GEOTIFF_VERSION_NUMBER
+    "((${GEOTIFF_VERSION_MAJOR})*100+${GEOTIFF_VERSION_MINOR})*100+${GEOTIFF_VERSION_PATCH}")
+else()
+  if(NOT GEOTIFF_FIND_QUIETLY)
+  message(WARNING "geotiff.h not found !")
+  endif()
+endif()
+
+
 set( GEOTIFF_NAMES ${GEOTIFF_NAMES} geotiff_i geotiff libgeotiff_i libgeotiff )
 find_library( GEOTIFF_LIBRARY NAMES ${GEOTIFF_NAMES} )