cmake: Add a finder for SIMD Everywhere

cmake/finders/FindSIMDE.cmake

@@ -0,0 +1,105 @@
+#[=======================================================================[.rst
+FindSIMDE
+---------
+
+FindModule for SIMD Everywhere
+
+Imported Targets
+^^^^^^^^^^^^^^^^
+
+.. versionadded:: 3.0
+
+This module defines the :prop_tgt:`IMPORTED` target ``SIMDE::SIMDE``.
+
+Result Variables
+^^^^^^^^^^^^^^^^
+
+This module sets the following variables:
+
+``SIMDE_FOUND``
+  True, if headers were found.
+``SIMDE_VERSION``
+  Detected version of found SIMDE Everywhere.
+
+Cache variables
+^^^^^^^^^^^^^^^
+
+The following cache variables may also be set:
+
+``SIMDE_INCLUDE_DIR``
+  Directory containing ``simde/simde-common.h``.
+
+#]=======================================================================]
+
+# cmake-format: off
+# cmake-lint: disable=C0103
+# cmake-lint: disable=C0301
+# cmake-format: on
+
+include(FindPackageHandleStandardArgs)
+
+find_package(PkgConfig QUIET)
+if(PKG_CONFIG_FOUND)
+  pkg_search_module(PC_SIMDE QUIET simde)
+endif()
+
+find_path(
+  SIMDE_INCLUDE_DIR
+  NAMES simde/simde-common.h
+  HINTS ${PC_SIMDE_INCLUDE_DIRS}
+  PATHS /usr/include /usr/local/include
+  DOC "SIMD Everywhere include directory"
+)
+
+if(EXISTS "${SIMDE_INCLUDE_DIR}/simde/simde-common.h")
+  file(
+    STRINGS
+    "${SIMDE_INCLUDE_DIR}/simde/simde-common.h"
+    _version_string
+    REGEX "^.*VERSION_(MAJOR|MINOR|MICRO)[ \t]+[0-9]+[ \t]*$"
+  )
+
+  string(REGEX REPLACE ".*VERSION_MAJOR[ \t]+([0-9]+).*" "\\1" _version_major "${_version_string}")
+  string(REGEX REPLACE ".*VERSION_MINOR[ \t]+([0-9]+).*" "\\1" _version_minor "${_version_string}")
+  string(REGEX REPLACE ".*VERSION_MICRO[ \t]+([0-9]+).*" "\\1" _version_release "${_version_string}")
+
+  set(SIMDE_VERSION "${_version_major}.${_version_minor}.${_version_release}")
+  unset(_version_major)
+  unset(_version_minor)
+  unset(_version_release)
+else()
+  if(NOT SIMDE_FIND_QUIETLY)
+    message(AUTHOR_WARNING "Failed to find SIMD Everywhere version.")
+  endif()
+  set(SIMDE_VERSION 0.0.0)
+endif()
+
+if(CMAKE_HOST_SYSTEM_NAME MATCHES "Darwin|Windows")
+  set(SIMDE_ERROR_REASON "Ensure that obs-deps is provided as part of CMAKE_PREFIX_PATH.")
+elseif(CMAKE_HOST_SYSTEM_NAME MATCHES "Linux|FreeBSD")
+  set(SIMDE_ERROR_REASON "Ensure SIMD Everywhere is available in local library paths.")
+endif()
+
+find_package_handle_standard_args(
+  SIMDE
+  REQUIRED_VARS SIMDE_INCLUDE_DIR
+  VERSION_VAR SIMDE_VERSION
+  REASON_FAILURE_MESSAGE "${SIMDE_ERROR_REASON}"
+)
+mark_as_advanced(SIMDE_INCLUDE_DIR)
+unset(SIMDE_ERROR_REASON)
+
+if(SIMDE_FOUND)
+  if(NOT TARGET SIMDE::SIMDE)
+    add_library(SIMDE::SIMDE INTERFACE IMPORTED)
+    set_target_properties(SIMDE::SIMDE PROPERTIES INTERFACE_INCLUDE_DIRECTORIES "${SIMDE_INCLUDE_DIR}")
+  endif()
+endif()
+
+include(FeatureSummary)
+set_package_properties(
+  SIMDE
+  PROPERTIES
+    URL "https://github.com/simd-everywhere/simde"
+    DESCRIPTION "Implementations of SIMD instruction sets for systems which don't natively support them. "
+)