CMake/Modules/FindSDL_sound.cmake

# Distributed under the OSI-approved BSD 3-Clause License.  See accompanying
# file LICENSE.rst or https://cmake.org/licensing for details.

#[=======================================================================[.rst:
FindSDL_sound
-------------

Finds the SDL_sound library, an abstract soundfile decoder for use in SDL
(Simple DirectMedia Layer) applications.

.. note::

  This module is specifically intended for SDL_sound version 1.  Starting with
  version 2.0.2, SDL_sound provides a CMake package configuration file when
  built with CMake and should be found using ``find_package(SDL2_sound)``.
  These newer versions provide :ref:`Imported Targets` that encapsulate usage
  requirements.  Refer to the upstream SDL_sound documentation for more
  information.

.. note::
  This module depends on SDL being found and must be called after the
  :module:`find_package(SDL) <FindSDL>`.

  Depending on how the SDL_sound library is built, it may require additional
  dependent libraries to be found for this module to succeed.  These
  dependencies may include MikMod, ModPlug, Ogg, Vorbis, SMPEG, FLAC, and Speex.

Result Variables
^^^^^^^^^^^^^^^^

This module defines the following variables:

``SDL_sound_FOUND``
  Boolean indicating whether the (requested version of) SDL_sound library is
  found.  For backward compatibility, the ``SDL_SOUND_FOUND`` variable is also
  set to the same value.

``SDL_SOUND_VERSION_STRING``
  The human-readable string containing the version of SDL_sound found.

``SDL_SOUND_LIBRARIES``
  Libraries needed to link against to use the SDL_sound library.

Cache Variables
^^^^^^^^^^^^^^^

The following cache variables may also be set:

``SDL_SOUND_INCLUDE_DIR``
  The directory containing the ``SDL_sound.h`` and other headers needed to use
  the SDL_sound library.

``SDL_SOUND_LIBRARY``
  The name of just the SDL_sound library you would link against.  Use
  ``SDL_SOUND_LIBRARIES`` for the link instructions and not this one.

``MIKMOD_LIBRARY``
  The path to the dependent MikMod library.

``MODPLUG_LIBRARY``
  The path to the dependent ModPlug library (libmodplug).

``OGG_LIBRARY``
  The path to the dependent Ogg library.

``VORBIS_LIBRARY``
  The path to the dependent Vorbis library.

``SMPEG_LIBRARY``
  The path to the dependent SMPEG library.

``FLAC_LIBRARY``
  The path to the dependent FLAC library.

``SPEEX_LIBRARY``
  The path to the dependent Speex library.

Hints
^^^^^

This module accepts the following variables:

``SDLDIR``
  Environment variable that can be set to help locate an SDL library installed
  in a custom location.  It should point to the installation destination that
  was used when configuring, building, and installing SDL library:
  ``./configure --prefix=$SDLDIR``.

  On macOS, setting this variable will prefer the Framework version (if found)
  over others.  In this case, the cache value of ``SDL_LIBRARY`` would need to
  be manually changed to override this selection or set the
  :variable:`CMAKE_INCLUDE_PATH` variable to modify the search paths.

``SDLSOUNDDIR``
  Environment variable that works the same as ``SDLDIR``.

``SDL_SOUND_EXTRAS``
  This is an optional cache variable that can be used to add additional flags
  that are prepended to the ``SDL_SOUND_LIBRARIES`` result variable.  This is
  available mostly for cases this module failed to anticipate for and additional
  flags must be added.

Examples
^^^^^^^^

Finding SDL_sound library and creating an imported interface target for linking
it to a project target:

.. code-block:: cmake

  find_package(SDL)
  find_package(SDL_sound)

  if(SDL_sound_FOUND AND NOT TARGET SDL::SDL_sound)
    add_library(SDL::SDL_sound INTERFACE IMPORTED)
    set_target_properties(
      SDL::SDL_sound
      PROPERTIES
        INTERFACE_INCLUDE_DIRECTORIES "${SDL_SOUND_INCLUDE_DIR}"
        INTERFACE_LINK_LIBRARIES "${SDL_SOUND_LIBRARIES}"
    )

    # Append the SDL dependency as imported target to be transitively linked:
    set_property(
      TARGET SDL::SDL_sound
      APPEND
      PROPERTY INTERFACE_LINK_LIBRARIES SDL::SDL
    )
  endif()

  target_link_libraries(project_target PRIVATE SDL::SDL_sound)

When working with SDL_sound version 2, the upstream package provides the
``SDL2_sound::SDL2_sound`` imported target directly.  It can be used in a
project without using this module:

.. code-block:: cmake

  find_package(SDL2_sound)
  target_link_libraries(project_target PRIVATE SDL2_sound::SDL2_sound)

See Also
^^^^^^^^

* The :module:`FindSDL` module to find the main SDL library.
#]=======================================================================]


#[[
This module is a bit more complicated than the
other FindSDL* family modules.  The reason is that SDL_sound can be
compiled in a large variety of different ways which are independent of
platform.  SDL_sound may dynamically link against other 3rd party
libraries to get additional codec support, such as Ogg Vorbis, SMPEG,
ModPlug, MikMod, FLAC, Speex, and potentially others.  Under some
circumstances which I don't fully understand, there seems to be a
requirement that dependent libraries of libraries you use must also be
explicitly linked against in order to successfully compile.  SDL_sound
does not currently have any system in place to know how it was
compiled.  So this CMake module does the hard work in trying to
discover which 3rd party libraries are required for building (if any).
This module uses a brute force approach to create a test program that
uses SDL_sound, and then tries to build it.  If the build fails, it
parses the error output for known symbol names to figure out which
libraries are needed.
#]]

cmake_policy(PUSH)
cmake_policy(SET CMP0159 NEW) # file(STRINGS) with REGEX updates CMAKE_MATCH_<n>

set(SDL_SOUND_EXTRAS "" CACHE STRING "SDL_sound extra flags")
mark_as_advanced(SDL_SOUND_EXTRAS)

# Find SDL_sound.h
find_path(SDL_SOUND_INCLUDE_DIR SDL_sound.h
  HINTS
    ENV SDLSOUNDDIR
    ENV SDLDIR
  PATH_SUFFIXES SDL
                # path suffixes to search inside ENV{SDLDIR}
                include/SDL include/SDL12 include/SDL11 include
  )

find_library(SDL_SOUND_LIBRARY
  NAMES SDL_sound
  HINTS
    ENV SDLSOUNDDIR
    ENV SDLDIR
  PATH_SUFFIXES lib VisualC/win32lib
  )

if(SDL_FOUND AND SDL_SOUND_INCLUDE_DIR AND SDL_SOUND_LIBRARY)

  # CMake is giving me problems using TRY_COMPILE with the CMAKE_FLAGS
  # for the :STRING syntax if I have multiple values contained in a
  # single variable. This is a problem for the SDL_LIBRARY variable
  # because it does just that. When I feed this variable to the command,
  # only the first value gets the appropriate modifier (e.g. -I) and
  # the rest get dropped.
  # To get multiple single variables to work, I must separate them with a "\;"
  # I could go back and modify the FindSDL.cmake module, but that's kind of painful.
  # The solution would be to try something like:
  # string(APPEND SDL_TRY_COMPILE_LIBRARY_LIST "\;${CMAKE_THREAD_LIBS_INIT}")
  # Instead, it was suggested on the mailing list to write a temporary CMakeLists.txt
  # with a temporary test project and invoke that with TRY_COMPILE.
  # See message thread "Figuring out dependencies for a library in order to build"
  # 2005-07-16
  #     try_compile(
  #             MY_RESULT
  #             ${CMAKE_BINARY_DIR}
  #             ${PROJECT_SOURCE_DIR}/DetermineSoundLibs.c
  #             CMAKE_FLAGS
  #                     -DINCLUDE_DIRECTORIES:STRING=${SDL_INCLUDE_DIR}\;${SDL_SOUND_INCLUDE_DIR}
  #                     -DLINK_LIBRARIES:STRING=${SDL_SOUND_LIBRARY}\;${SDL_LIBRARY}
  #             OUTPUT_VARIABLE MY_OUTPUT
  #     )

  # To minimize external dependencies, create a sdlsound test program
  # which will be used to figure out if additional link dependencies are
  # required for the link phase.
  file(WRITE ${PROJECT_BINARY_DIR}/CMakeTmp/DetermineSoundLibs.c
    "#include \"SDL_sound.h\"
    #include \"SDL.h\"
    int main(int argc, char* argv[])
    {
        Sound_AudioInfo desired;
        Sound_Sample* sample;

        SDL_Init(0);
        Sound_Init();

        /* This doesn't actually have to work, but Init() is a no-op
         * for some of the decoders, so this should force more symbols
         * to be pulled in.
         */
        sample = Sound_NewSampleFromFile(argv[1], &desired, 4096);

        Sound_Quit();
        SDL_Quit();
        return 0;
     }"
  )

  # Calling
  # target_link_libraries(DetermineSoundLibs "${SDL_SOUND_LIBRARY} ${SDL_LIBRARY})
  # causes problems when SDL_LIBRARY looks like
  # /Library/Frameworks/SDL.framework;-framework Cocoa
  # The ;-framework Cocoa seems to be confusing CMake once the OS X
  # framework support was added. I was told that breaking up the list
  # would fix the problem.
  set(TMP_TRY_LIBS)
  foreach(lib ${SDL_SOUND_LIBRARY} ${SDL_LIBRARY})
    string(APPEND TMP_TRY_LIBS " \"${lib}\"")
  endforeach()


  # Write the CMakeLists.txt and test project
  # Weird, this is still sketchy. If I don't quote the variables
  # in the TARGET_LINK_LIBRARIES, I seem to loose everything
  # in the SDL_LIBRARY string after the "-framework".
  # But if I quote the stuff in INCLUDE_DIRECTORIES, it doesn't work.
  file(WRITE ${PROJECT_BINARY_DIR}/CMakeTmp/CMakeLists.txt
    "cmake_minimum_required(VERSION ${CMAKE_VERSION})
     project(DetermineSoundLibs)
     include_directories(${SDL_INCLUDE_DIR} ${SDL_SOUND_INCLUDE_DIR})
     add_executable(DetermineSoundLibs DetermineSoundLibs.c)
     target_link_libraries(DetermineSoundLibs ${TMP_TRY_LIBS})"
    )

  try_compile(
    MY_RESULT
    PROJECT DetermineSoundLibs
    SOURCE_DIR ${PROJECT_BINARY_DIR}/CMakeTmp
    BINARY_DIR ${PROJECT_BINARY_DIR}/CMakeTmp
    OUTPUT_VARIABLE MY_OUTPUT
    )


  if(NOT MY_RESULT)

    # I expect that MPGLIB, VOC, WAV, AIFF, and SHN are compiled in statically.
    # I think Timidity is also compiled in statically.
    # I've never had to explicitly link against Quicktime, so I'll skip that for now.

    set(SDL_SOUND_LIBRARIES_TMP ${SDL_SOUND_LIBRARY})

    # Find MikMod
    if("${MY_OUTPUT}" MATCHES "MikMod_")
      find_library(MIKMOD_LIBRARY
        NAMES libmikmod-coreaudio mikmod
        PATHS
          ENV MIKMODDIR
          ENV SDLSOUNDDIR
          ENV SDLDIR
          /opt
        PATH_SUFFIXES
          lib
      )
      if(MIKMOD_LIBRARY)
        set(SDL_SOUND_LIBRARIES_TMP ${SDL_SOUND_LIBRARIES_TMP} ${MIKMOD_LIBRARY})
      endif()
    endif()

    # Find ModPlug
    if("${MY_OUTPUT}" MATCHES "MODPLUG_")
      find_library(MODPLUG_LIBRARY
        NAMES modplug
        PATHS
          ENV MODPLUGDIR
          ENV SDLSOUNDDIR
          ENV SDLDIR
          /opt
        PATH_SUFFIXES
          lib
      )
      if(MODPLUG_LIBRARY)
        set(SDL_SOUND_LIBRARIES_TMP ${SDL_SOUND_LIBRARIES_TMP} ${MODPLUG_LIBRARY})
      endif()
    endif()


    # Find Ogg and Vorbis
    if("${MY_OUTPUT}" MATCHES "ov_")
      find_library(VORBIS_LIBRARY
        NAMES vorbis Vorbis VORBIS
        PATHS
          ENV VORBISDIR
          ENV OGGDIR
          ENV SDLSOUNDDIR
          ENV SDLDIR
          /opt
        PATH_SUFFIXES
          lib
        )
      if(VORBIS_LIBRARY)
        set(SDL_SOUND_LIBRARIES_TMP ${SDL_SOUND_LIBRARIES_TMP} ${VORBIS_LIBRARY})
      endif()

      find_library(OGG_LIBRARY
        NAMES ogg Ogg OGG
        PATHS
          ENV OGGDIR
          ENV VORBISDIR
          ENV SDLSOUNDDIR
          ENV SDLDIR
          /opt
        PATH_SUFFIXES
          lib
         )
      if(OGG_LIBRARY)
        set(SDL_SOUND_LIBRARIES_TMP ${SDL_SOUND_LIBRARIES_TMP} ${OGG_LIBRARY})
      endif()
    endif()


    # Find SMPEG
    if("${MY_OUTPUT}" MATCHES "SMPEG_")
      find_library(SMPEG_LIBRARY
        NAMES smpeg SMPEG Smpeg SMpeg
        PATHS
          ENV SMPEGDIR
          ENV SDLSOUNDDIR
          ENV SDLDIR
          /opt
        PATH_SUFFIXES
          lib
        )
      if(SMPEG_LIBRARY)
        set(SDL_SOUND_LIBRARIES_TMP ${SDL_SOUND_LIBRARIES_TMP} ${SMPEG_LIBRARY})
      endif()
    endif()


    # Find FLAC
    if("${MY_OUTPUT}" MATCHES "FLAC_")
      find_library(FLAC_LIBRARY
        NAMES flac FLAC
        PATHS
          ENV FLACDIR
          ENV SDLSOUNDDIR
          ENV SDLDIR
          /opt
        PATH_SUFFIXES
          lib
        )
      if(FLAC_LIBRARY)
        set(SDL_SOUND_LIBRARIES_TMP ${SDL_SOUND_LIBRARIES_TMP} ${FLAC_LIBRARY})
      endif()
    endif()


    # Hmmm...Speex seems to depend on Ogg. This might be a problem if
    # the TRY_COMPILE attempt gets blocked at SPEEX before it can pull
    # in the Ogg symbols. I'm not sure if I should duplicate the ogg stuff
    # above for here or if two ogg entries will screw up things.
    if("${MY_OUTPUT}" MATCHES "speex_")
      find_library(SPEEX_LIBRARY
        NAMES speex SPEEX
        PATHS
          ENV SPEEXDIR
          ENV SDLSOUNDDIR
          ENV SDLDIR
          /opt
        PATH_SUFFIXES
          lib
        )
      if(SPEEX_LIBRARY)
        set(SDL_SOUND_LIBRARIES_TMP ${SDL_SOUND_LIBRARIES_TMP} ${SPEEX_LIBRARY})
      endif()

      # Find OGG (needed for Speex)
      # We might have already found Ogg for Vorbis, so skip it if so.
      if(NOT OGG_LIBRARY)
        find_library(OGG_LIBRARY
          NAMES ogg Ogg OGG
          PATHS
            ENV OGGDIR
            ENV VORBISDIR
            ENV SPEEXDIR
            ENV SDLSOUNDDIR
            ENV SDLDIR
            /opt
          PATH_SUFFIXES lib
          )
        if(OGG_LIBRARY)
          set(SDL_SOUND_LIBRARIES_TMP ${SDL_SOUND_LIBRARIES_TMP} ${OGG_LIBRARY})
        endif()
      endif()
    endif()

    set(SDL_SOUND_LIBRARIES ${SDL_SOUND_EXTRAS} ${SDL_SOUND_LIBRARIES_TMP})
  else()
    set(SDL_SOUND_LIBRARIES ${SDL_SOUND_EXTRAS} ${SDL_SOUND_LIBRARY})
  endif()
 endif()

if(SDL_SOUND_INCLUDE_DIR AND EXISTS "${SDL_SOUND_INCLUDE_DIR}/SDL_sound.h")
  file(STRINGS "${SDL_SOUND_INCLUDE_DIR}/SDL_sound.h" SDL_SOUND_VERSION_MAJOR_LINE REGEX "^#define[ \t]+SOUND_VER_MAJOR[ \t]+[0-9]+$")
  file(STRINGS "${SDL_SOUND_INCLUDE_DIR}/SDL_sound.h" SDL_SOUND_VERSION_MINOR_LINE REGEX "^#define[ \t]+SOUND_VER_MINOR[ \t]+[0-9]+$")
  file(STRINGS "${SDL_SOUND_INCLUDE_DIR}/SDL_sound.h" SDL_SOUND_VERSION_PATCH_LINE REGEX "^#define[ \t]+SOUND_VER_PATCH[ \t]+[0-9]+$")
  string(REGEX REPLACE "^#define[ \t]+SOUND_VER_MAJOR[ \t]+([0-9]+)$" "\\1" SDL_SOUND_VERSION_MAJOR "${SDL_SOUND_VERSION_MAJOR_LINE}")
  string(REGEX REPLACE "^#define[ \t]+SOUND_VER_MINOR[ \t]+([0-9]+)$" "\\1" SDL_SOUND_VERSION_MINOR "${SDL_SOUND_VERSION_MINOR_LINE}")
  string(REGEX REPLACE "^#define[ \t]+SOUND_VER_PATCH[ \t]+([0-9]+)$" "\\1" SDL_SOUND_VERSION_PATCH "${SDL_SOUND_VERSION_PATCH_LINE}")
  set(SDL_SOUND_VERSION_STRING ${SDL_SOUND_VERSION_MAJOR}.${SDL_SOUND_VERSION_MINOR}.${SDL_SOUND_VERSION_PATCH})
  unset(SDL_SOUND_VERSION_MAJOR_LINE)
  unset(SDL_SOUND_VERSION_MINOR_LINE)
  unset(SDL_SOUND_VERSION_PATCH_LINE)
  unset(SDL_SOUND_VERSION_MAJOR)
  unset(SDL_SOUND_VERSION_MINOR)
  unset(SDL_SOUND_VERSION_PATCH)
endif()

include(FindPackageHandleStandardArgs)

find_package_handle_standard_args(SDL_sound
                                  REQUIRED_VARS SDL_SOUND_LIBRARY SDL_SOUND_INCLUDE_DIR
                                  VERSION_VAR SDL_SOUND_VERSION_STRING)

cmake_policy(POP)