FindBoost.cmake (DONT'T DELETE THIS! It's linked in a Stack Overflow answer)

FindBoost.cmake

# - Find Boost
# 
# Copyright (c) 2016 Thiago Barroso Perrotta
# 
# Permission is hereby granted, free of charge, to any person obtaining a copy of
# this software and associated documentation files (the "Software"), to deal in
# the Software without restriction, including without limitation the rights to
# use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
# the Software, and to permit persons to whom the Software is furnished to do so,
# subject to the following conditions:
# 
# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.
# 
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
# FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
# COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
# IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
# CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
#
# This module finds if Boost is installed and determines where the
# executables are. It sets the following variables:
#
#  BOOST_FOUND : boolean            - system has Boost
#  BOOST_LIBRARIES : list(filepath) - the libraries needed to use Boost
#  BOOST_INCLUDE_DIRS : list(path)  - the Boost include directories
#
# If Boost is not found, this module downloads it according to the
# following variables:
#
#  BOOST_ROOT_DIR : path                - the Path where Boost will be installed on
#  BOOST_REQUESTED_VERSION : string     - the Boost version to be downloaded
#
# You can also specify its components:
#
#  find_package(Boost COMPONENTS program_options system)
#
# which are stored in Boost_FIND_COMPONENTS : list(string)
#
# You can also specify its behavior:
#
#  BOOST_USE_STATIC_LIBS : boolean (default: OFF)

if(NOT Boost_FIND_COMPONENTS)
	message(FATAL_ERROR "No COMPONENTS specified for Boost")
endif()

set(BOOST_USE_STATIC_LIBS false)

# Set the library prefix and library suffix properly.
if(BOOST_USE_STATIC_LIBS)
	set(CMAKE_FIND_LIBRARY_PREFIXES ${CMAKE_STATIC_LIBRARY_PREFIX})
	set(CMAKE_FIND_LIBRARY_SUFFIXES ${CMAKE_STATIC_LIBRARY_SUFFIX})
	set(LIBRARY_PREFIX ${CMAKE_STATIC_LIBRARY_PREFIX})
	set(LIBRARY_SUFFIX ${CMAKE_STATIC_LIBRARY_SUFFIX})
else()
	set(CMAKE_FIND_LIBRARY_PREFIXES ${CMAKE_SHARED_LIBRARY_PREFIX})
	set(CMAKE_FIND_LIBRARY_SUFFIXES ${CMAKE_SHARED_LIBRARY_SUFFIX})
	set(LIBRARY_PREFIX ${CMAKE_SHARED_LIBRARY_PREFIX})
	set(LIBRARY_SUFFIX ${CMAKE_SHARED_LIBRARY_SUFFIX})
endif()

# Create a list(string) for the build command (e.g. --with-program_options;--with-system)
# and assigns it to BOOST_COMPONENTS_FOR_BUILD
foreach(component ${Boost_FIND_COMPONENTS})
	list(APPEND BOOST_COMPONENTS_FOR_BUILD --with-${component})
endforeach()

# Create a string for the first component (e.g. boost_program_options)
# and assigns it to Boost_FIND_COMPONENTS
list(GET Boost_FIND_COMPONENTS 0 BOOST_FIRST_COMPONENT)
set(BOOST_FIRST_COMPONENT "boost_${BOOST_FIRST_COMPONENT}")

include(FindPackageHandleStandardArgs)

macro(DO_FIND_BOOST_SYSTEM)
	find_path(BOOST_INCLUDE_DIR boost/config.hpp
		PATHS /usr/local/include /usr/include
		)
	find_library(BOOST_LIBRARY
		NAMES ${BOOST_FIRST_COMPONENT}
		PATHS /usr/local/lib /usr/lib
		)
	FIND_PACKAGE_HANDLE_STANDARD_ARGS(Boost DEFAULT_MSG
		BOOST_INCLUDE_DIR BOOST_LIBRARY
		)
	set(BOOST_LIBRARIES ${BOOST_LIBRARY})
	set(BOOST_INCLUDE_DIRS ${BOOST_INCLUDE_DIR})
	mark_as_advanced(BOOST_LIBRARIES BOOST_INCLUDE_DIRS)
endmacro()

macro(DO_FIND_BOOST_ROOT)
	if(NOT BOOST_ROOT_DIR)
		message(STATUS "BOOST_ROOT_DIR is not defined, using binary directory.")
		set(BOOST_ROOT_DIR ${CURRENT_CMAKE_BINARY_DIR} CACHE PATH "")
	endif()

	find_path(BOOST_INCLUDE_DIR boost/config.hpp ${BOOST_ROOT_DIR}/include)
	find_library(BOOST_LIBRARY ${BOOST_FIRST_COMPONENT} HINTS ${BOOST_ROOT_DIR}/lib)
	FIND_PACKAGE_HANDLE_STANDARD_ARGS(Boost DEFAULT_MSG
		BOOST_INCLUDE_DIR BOOST_LIBRARY
		)
	set(BOOST_LIBRARIES ${BOOST_LIBRARY})
	set(BOOST_INCLUDE_DIRS ${BOOST_INCLUDE_DIR})
	mark_as_advanced(BOOST_LIBRARIES BOOST_INCLUDE_DIRS)
endmacro()

macro(DO_FIND_BOOST_DOWNLOAD)
	if(NOT BOOST_REQUESTED_VERSION)
		message(FATAL_ERROR "BOOST_REQUESTED_VERSION is not defined.")
	endif()

	string(REPLACE "." "_" BOOST_REQUESTED_VERSION_UNDERSCORE ${BOOST_REQUESTED_VERSION})

	set(BOOST_MAYBE_STATIC)
	if(BOOST_USE_STATIC_LIBS)
		set(BOOST_MAYBE_STATIC "link=static")
	endif()

	include(ExternalProject)
	ExternalProject_Add(
		Boost
		URL https://downloads.sourceforge.net/project/boost/boost/${BOOST_REQUESTED_VERSION}/boost_${BOOST_REQUESTED_VERSION_UNDERSCORE}.zip
		UPDATE_COMMAND ""
		CONFIGURE_COMMAND ./bootstrap.sh --prefix=${BOOST_ROOT_DIR}
		BUILD_COMMAND ./b2 ${BOOST_MAYBE_STATIC} --prefix=${BOOST_ROOT_DIR} ${BOOST_COMPONENTS_FOR_BUILD} install
		BUILD_IN_SOURCE true
		INSTALL_COMMAND ""
		INSTALL_DIR ${BOOST_ROOT_DIR}
		)

	ExternalProject_Get_Property(Boost install_dir)
	set(BOOST_INCLUDE_DIRS ${install_dir}/include)

	macro(libraries_to_fullpath varname)
		set(${varname})
		foreach(component ${Boost_FIND_COMPONENTS})
			list(APPEND ${varname} ${BOOST_ROOT_DIR}/lib/${LIBRARY_PREFIX}boost_${component}${LIBRARY_SUFFIX})
		endforeach()
	endmacro()
	libraries_to_fullpath(BOOST_LIBRARIES)

	FIND_PACKAGE_HANDLE_STANDARD_ARGS(Boost DEFAULT_MSG
		BOOST_INCLUDE_DIRS BOOST_LIBRARIES
		)
	mark_as_advanced(BOOST_LIBRARIES BOOST_INCLUDE_DIRS)
endmacro()

if(NOT BOOST_FOUND)
	DO_FIND_BOOST_ROOT()
endif()

if(NOT BOOST_FOUND)
	DO_FIND_BOOST_SYSTEM()
endif()

if(NOT BOOST_FOUND)
	DO_FIND_BOOST_DOWNLOAD()
endif()