#.rst:
# FindOpenCL
# ----------
#
# Try to find OpenCL
#
# Once done this will define::
#
#   OpenCL_FOUND          - True if OpenCL was found
#   OpenCL_INCLUDE_DIRS   - include directories for OpenCL
#   OpenCL_LIBRARIES      - link against this library to use OpenCL
#   OpenCL_VERSION_STRING - Highest supported OpenCL version (eg. 1.2)
#   OpenCL_VERSION_MAJOR  - The major version of the OpenCL implementation
#   OpenCL_VERSION_MINOR  - The minor version of the OpenCL implementation
#
# The module will also define two cache variables::
#
#   OpenCL_INCLUDE_DIR    - the OpenCL include directory
#   OpenCL_LIBRARY        - the path to the OpenCL library
#

#=============================================================================
# Copyright 2014 Matthaeus G. Chajdas
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# 
# * Redistributions of source code must retain the above copyright
#   notice, this list of conditions and the following disclaimer.
# 
# * Redistributions in binary form must reproduce the above copyright
#   notice, this list of conditions and the following disclaimer in the
#   documentation and/or other materials provided with the distribution.
# 
# * Neither the names of Kitware, Inc., the Insight Software Consortium,
#   nor the names of their contributors may be used to endorse or promote
#   products derived from this software without specific prior written
#   permission.
# 
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
# HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#=============================================================================

function(_FIND_OPENCL_VERSION)
  include(CheckSymbolExists)
  include(CMakePushCheckState)
  set(CMAKE_REQUIRED_QUIET ${OpenCL_FIND_QUIETLY})

  CMAKE_PUSH_CHECK_STATE()
  foreach(VERSION "2_0" "1_2" "1_1" "1_0")
    set(CMAKE_REQUIRED_INCLUDES "${OpenCL_INCLUDE_DIR}")

    if(APPLE)
      CHECK_SYMBOL_EXISTS(
        CL_VERSION_${VERSION}
        "${OpenCL_INCLUDE_DIR}/OpenCL/cl.h"
        OPENCL_VERSION_${VERSION})
    else()
      CHECK_SYMBOL_EXISTS(
        CL_VERSION_${VERSION}
        "${OpenCL_INCLUDE_DIR}/CL/cl.h"
        OPENCL_VERSION_${VERSION})
    endif()

    if(OPENCL_VERSION_${VERSION})
      string(REPLACE "_" "." VERSION "${VERSION}")
      set(OpenCL_VERSION_STRING ${VERSION} PARENT_SCOPE)
      string(REGEX MATCHALL "[0-9]+" version_components "${VERSION}")
      list(GET version_components 0 major_version)
      list(GET version_components 1 minor_version)
      set(OpenCL_VERSION_MAJOR ${major_version} PARENT_SCOPE)
      set(OpenCL_VERSION_MINOR ${minor_version} PARENT_SCOPE)
      break()
    endif()
  endforeach()
  CMAKE_POP_CHECK_STATE()
endfunction()

find_path(OpenCL_INCLUDE_DIR
  NAMES
    CL/cl.h OpenCL/cl.h
  PATHS
    ENV "PROGRAMFILES(X86)"
    ENV AMDAPPSDKROOT
    ENV INTELOCLSDKROOT
    ENV NVSDKCOMPUTE_ROOT
    ENV CUDA_PATH
    ENV ATISTREAMSDKROOT
  PATH_SUFFIXES
    include
    OpenCL/common/inc
    "AMD APP/include")

_FIND_OPENCL_VERSION()

if(WIN32)
  if(CMAKE_SIZEOF_VOID_P EQUAL 4)
    find_library(OpenCL_LIBRARY
      NAMES OpenCL
      PATHS
        ENV "PROGRAMFILES(X86)"
        ENV AMDAPPSDKROOT
        ENV INTELOCLSDKROOT
        ENV CUDA_PATH
        ENV NVSDKCOMPUTE_ROOT
        ENV ATISTREAMSDKROOT
      PATH_SUFFIXES
        "AMD APP/lib/x86"
        lib/x86
        lib/Win32
        OpenCL/common/lib/Win32)
  elseif(CMAKE_SIZEOF_VOID_P EQUAL 8)
    find_library(OpenCL_LIBRARY
      NAMES OpenCL
      PATHS
        ENV "PROGRAMFILES(X86)"
        ENV AMDAPPSDKROOT
        ENV INTELOCLSDKROOT
        ENV CUDA_PATH
        ENV NVSDKCOMPUTE_ROOT
        ENV ATISTREAMSDKROOT
      PATH_SUFFIXES
        "AMD APP/lib/x86_64"
        lib/x86_64
        lib/x64
        OpenCL/common/lib/x64)
  endif()
else()
  find_library(OpenCL_LIBRARY
    NAMES OpenCL)
endif()

set(OpenCL_LIBRARIES ${OpenCL_LIBRARY})
set(OpenCL_INCLUDE_DIRS ${OpenCL_INCLUDE_DIR})

include(FindPackageHandleStandardArgs)
find_package_handle_standard_args(
  OpenCL
  FOUND_VAR OpenCL_FOUND
  REQUIRED_VARS OpenCL_LIBRARY OpenCL_INCLUDE_DIR
  VERSION_VAR OpenCL_VERSION_STRING)

mark_as_advanced(
  OpenCL_INCLUDE_DIR
  OpenCL_LIBRARY)
