# - Try to find the OpenSSL encryption library
    # Once done this will define
    #
    #  OPENSSL_ROOT_DIR - Set this variable to the root installation of OpenSSL
    #
    # Read-Only variables:
    #  OPENSSL_FOUND - system has the OpenSSL library
    #  OPENSSL_INCLUDE_DIR - the OpenSSL include directory
    #  OPENSSL_LIBRARIES - The libraries needed to use OpenSSL
    #  OPENSSL_VERSION - This is set to $major.$minor.$revision (eg. 0.9.8)
     
    #=============================================================================
    # Copyright 2006-2009 Kitware, Inc.
    # Copyright 2006 Alexander Neundorf <neundorf@kde.org>
    # Copyright 2009-2011 Mathieu Malaterre <mathieu.malaterre@gmail.com>
    #
    # Distributed under the OSI-approved BSD License (the "License");
    # see accompanying file Copyright.txt for details.
    #
    # This software is distributed WITHOUT ANY WARRANTY; without even the
    # implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
    # See the License for more information.
    #=============================================================================
    # (To distribute this file outside of CMake, substitute the full
    #  License text for the above reference.)
     
    if (UNIX)
      find_package(PkgConfig)
      if (PKG_CONFIG_FOUND)
        pkg_check_modules(_OPENSSL openssl)
      endif (PKG_CONFIG_FOUND)
    endif (UNIX)
     
    # http://www.slproweb.com/products/Win32OpenSSL.html
    SET(_OPENSSL_ROOT_HINTS
      $ENV{OPENSSL_ROOT_DIR}
      ${OPENSSL_ROOT_DIR}
      "[HKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Uninstall\\OpenSSL (32-bit)_is1;Inno Setup: App Path]"
      "[HKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\Uninstall\\OpenSSL (64-bit)_is1;Inno Setup: App Path]"
      )
    SET(_OPENSSL_ROOT_PATHS
      "$ENV{PROGRAMFILES}/OpenSSL"
      "$ENV{PROGRAMFILES}/OpenSSL-Win32"
      "$ENV{PROGRAMFILES}/OpenSSL-Win64"
      "C:/OpenSSL/"
      "C:/OpenSSL-Win32/"
      "C:/OpenSSL-Win64/"
      )
    SET(_OPENSSL_ROOT_HINTS_AND_PATHS
      HINTS ${_OPENSSL_ROOT_HINTS}
      PATHS ${_OPENSSL_ROOT_PATHS}
      )
     
    FIND_PATH(OPENSSL_INCLUDE_DIR
      NAMES
        openssl/ssl.h
      HINTS
        ${_OPENSSL_INCLUDEDIR}
      ${_OPENSSL_ROOT_HINTS_AND_PATHS}
      PATH_SUFFIXES
        include
    )
     
    IF(WIN32 AND NOT CYGWIN)
      # MINGW should go here too
      IF(MSVC)
        # /MD and /MDd are the standard values - if someone wants to use
        # others, the libnames have to change here too
        # use also ssl and ssleay32 in debug as fallback for openssl < 0.9.8b
        # TODO: handle /MT and static lib
        # In Visual C++ naming convention each of these four kinds of Windows libraries has it's standard suffix:
        #   * MD for dynamic-release
        #   * MDd for dynamic-debug
        #   * MT for static-release
        #   * MTd for static-debug
     
        # Implementation details:
        # We are using the libraries located in the VC subdir instead of the parent directory eventhough :
        # libeay32MD.lib is identical to ../libeay32.lib, and
        # ssleay32MD.lib is identical to ../ssleay32.lib
        FIND_LIBRARY(LIB_EAY_DEBUG
          NAMES
            libeay32MDd
            libeay32
          ${_OPENSSL_ROOT_HINTS_AND_PATHS}
          PATH_SUFFIXES
            "lib"
            "VC"
            "lib/VC"
        )
     
        FIND_LIBRARY(LIB_EAY_RELEASE
          NAMES
            libeay32MD
            libeay32
          ${_OPENSSL_ROOT_HINTS_AND_PATHS}
          PATH_SUFFIXES
            "lib"
            "VC"
            "lib/VC"
        )
     
        FIND_LIBRARY(SSL_EAY_DEBUG
          NAMES
            ssleay32MDd
            ssleay32
            ssl
          ${_OPENSSL_ROOT_HINTS_AND_PATHS}
          PATH_SUFFIXES
            "lib"
            "VC"
            "lib/VC"
        )
     
        FIND_LIBRARY(SSL_EAY_RELEASE
          NAMES
            ssleay32MD
            ssleay32
            ssl
          ${_OPENSSL_ROOT_HINTS_AND_PATHS}
          PATH_SUFFIXES
            "lib"
            "VC"
            "lib/VC"
        )
     
        if( CMAKE_CONFIGURATION_TYPES OR CMAKE_BUILD_TYPE )
          set( OPENSSL_LIBRARIES
            optimized ${SSL_EAY_RELEASE} debug ${SSL_EAY_DEBUG}
            optimized ${LIB_EAY_RELEASE} debug ${LIB_EAY_DEBUG}
            )
        else()
          set( OPENSSL_LIBRARIES ${SSL_EAY_RELEASE} ${LIB_EAY_RELEASE} )
        endif()
        MARK_AS_ADVANCED(SSL_EAY_DEBUG SSL_EAY_RELEASE)
        MARK_AS_ADVANCED(LIB_EAY_DEBUG LIB_EAY_RELEASE)
      ELSEIF(MINGW)
        # same player, for MingW
        FIND_LIBRARY(LIB_EAY
          NAMES
            libeay32
          ${_OPENSSL_ROOT_HINTS_AND_PATHS}
          PATH_SUFFIXES
            "lib"
            "lib/MinGW"
        )
     
        FIND_LIBRARY(SSL_EAY
          NAMES
            ssleay32
          ${_OPENSSL_ROOT_HINTS_AND_PATHS}
          PATH_SUFFIXES
            "lib"
            "lib/MinGW"
        )
     
        MARK_AS_ADVANCED(SSL_EAY LIB_EAY)
        set( OPENSSL_LIBRARIES ${SSL_EAY} ${LIB_EAY} )
      ELSE(MSVC)
        # Not sure what to pick for -say- intel, let's use the toplevel ones and hope someone report issues:
        FIND_LIBRARY(LIB_EAY
          NAMES
            libeay32
          HINTS
            ${_OPENSSL_LIBDIR}
          ${_OPENSSL_ROOT_HINTS_AND_PATHS}
          PATH_SUFFIXES
            lib
        )
     
        FIND_LIBRARY(SSL_EAY
          NAMES
            ssleay32
          HINTS
            ${_OPENSSL_LIBDIR}
          ${_OPENSSL_ROOT_HINTS_AND_PATHS}
          PATH_SUFFIXES
            lib
        )
     
        MARK_AS_ADVANCED(SSL_EAY LIB_EAY)
        set( OPENSSL_LIBRARIES ${SSL_EAY} ${LIB_EAY} )
      ENDIF(MSVC)
    ELSE(WIN32 AND NOT CYGWIN)
     
      FIND_LIBRARY(OPENSSL_SSL_LIBRARY
        NAMES
          ssl
          ssleay32
          ssleay32MD
        HINTS
          ${_OPENSSL_LIBDIR}
        ${_OPENSSL_ROOT_HINTS_AND_PATHS}
        PATH_SUFFIXES
          lib
      )
     
      FIND_LIBRARY(OPENSSL_CRYPTO_LIBRARY
        NAMES
          crypto
        HINTS
          ${_OPENSSL_LIBDIR}
        ${_OPENSSL_ROOT_HINTS_AND_PATHS}
        PATH_SUFFIXES
          lib
      )
     
      MARK_AS_ADVANCED(OPENSSL_CRYPTO_LIBRARY OPENSSL_SSL_LIBRARY)
     
      # compat defines
      SET(OPENSSL_SSL_LIBRARIES ${OPENSSL_SSL_LIBRARY})
      SET(OPENSSL_CRYPTO_LIBRARIES ${OPENSSL_CRYPTO_LIBRARY})
     
      SET(OPENSSL_LIBRARIES ${OPENSSL_SSL_LIBRARY} ${OPENSSL_CRYPTO_LIBRARY})
     
    ENDIF(WIN32 AND NOT CYGWIN)
     
    if (OPENSSL_INCLUDE_DIR)
      file(STRINGS "${OPENSSL_INCLUDE_DIR}/openssl/opensslv.h" openssl_version_str REGEX "^#define[\t ]+OPENSSL_VERSION_NUMBER[\t ]+0x[0-9][0-9][0-9][0-9][0-9][0-9].*")
     
      string(REGEX REPLACE "^.*OPENSSL_VERSION_NUMBER[\t ]+0x([0-9]).*$" "\\1" OPENSSL_VERSION_MAJOR "${openssl_version_str}")
      string(REGEX REPLACE "^.*OPENSSL_VERSION_NUMBER[\t ]+0x[0-9]([0-9][0-9]).*$" "\\1" OPENSSL_VERSION_MINOR  "${openssl_version_str}")
      string(REGEX REPLACE "^.*OPENSSL_VERSION_NUMBER[\t ]+0x[0-9][0-9][0-9]([0-9][0-9]).*$" "\\1" OPENSSL_VERSION_PATCH "${openssl_version_str}")
     
      string(REGEX REPLACE "^0" "" OPENSSL_VERSION_MINOR "${OPENSSL_VERSION_MINOR}")
      string(REGEX REPLACE "^0" "" OPENSSL_VERSION_PATCH "${OPENSSL_VERSION_PATCH}")
     
      set(OPENSSL_VERSION "${OPENSSL_VERSION_MAJOR}.${OPENSSL_VERSION_MINOR}.${OPENSSL_VERSION_PATCH}")
    endif (OPENSSL_INCLUDE_DIR)
     
    include(FindPackageHandleStandardArgs)
     
    if (OPENSSL_VERSION)
      find_package_handle_standard_args(OpenSSL
        REQUIRED_VARS
          OPENSSL_LIBRARIES
          OPENSSL_INCLUDE_DIR
        VERSION_VAR
          OPENSSL_VERSION
        FAIL_MESSAGE
          "Could NOT find OpenSSL, try to set the path to OpenSSL root folder in the system variable OPENSSL_ROOT_DIR"
      )
    else (OPENSSL_VERSION)
      find_package_handle_standard_args(OpenSSL "Could NOT find OpenSSL, try to set the path to OpenSSL root folder in the system variable OPENSSL_ROOT_DIR"
        OPENSSL_LIBRARIES
        OPENSSL_INCLUDE_DIR
      )
    endif (OPENSSL_VERSION)
     
    MARK_AS_ADVANCED(OPENSSL_INCLUDE_DIR OPENSSL_LIBRARIES)