Add dependency on google-sparsehash

CMakeLists.txt

@@ -240,6 +240,12 @@ check_taglib_filename( COMPLEX_TAGLIB_FILENAME )
 find_package(Boost REQUIRED)
 macro_log_feature(Boost_FOUND "Boost" "Provides free peer-reviewed portable C++ source libraries" "http://www.boost.org" TRUE "" "") #FIXME: give useful explanation
 
+macro_optional_find_package(Sparsehash)
+macro_log_feature(SPARSEHASH_FOUND "Sparsehash"
+    "https://code.google.com/p/sparsehash/" "" TRUE ""
+    "Sparsehash is needed for reading metadata of mediastreams and fast
+    forward/backward seeking in HTTP streams")
+
 macro_optional_find_package(QCA2)
 macro_log_feature(QCA2_FOUND "QCA2" "Provides encryption and signing functions necessary for some resolvers and accounts" "http://delta.affinix.com/qca/" TRUE "" "")
 

CMakeModules/FindSparsehash.cmake

@@ -0,0 +1,25 @@
+# - Find google-sparsehash
+# Find the google-sparsehash includes
+# This module defines
+# SPARSEHASH_INCLUDE_DIR, root jreen include dir.
+# SPARSEHASH_FOUND, whether libjreen was found
+
+FIND_PACKAGE(PkgConfig QUIET)
+PKG_CHECK_MODULES(PC_SPARSEHASH QUIET libsparsehash)
+
+FIND_PATH(SPARSEHASH_INCLUDE_DIR NAMES google/sparsetable
+    HINTS
+        ${PC_SPARSEHASH_INCLUDEDIR}
+        ${PC_SPARSEHASH_INCLUDE_DIRS}
+        ${CMAKE_INSTALL_INCLUDEDIR}
+)
+
+IF(SPARSEHASH_INCLUDE_DIR AND NOT PC_SPARSEHASH_VERSION)
+    MESSAGE(WARNING "You don't have pkg-config and so the google-sparsehash version check does not work!")
+ENDIF()
+
+INCLUDE(FindPackageHandleStandardArgs)
+FIND_PACKAGE_HANDLE_STANDARD_ARGS(Sparsehash
+    REQUIRED_VARS SPARSEHASH_INCLUDE_DIR)
+
+MARK_AS_ADVANCED(SPARSEHASH_INCLUDE_DIR)