# __________________________________________________________________________ __ _
# get_git_version:
# Obtain version string from git tags via git_describe and parse result into
# convenient version variables.
#
# Tags have to be in the format .*([0-9]+)\.([0-9]+)\.([0-9]+)-(.*), as in
# v1.2.3-rc5, where the expressions in parentheses are interpreted as major,
# minor, patch and extra (package release) version numbers.
#
# Usage:
# include(GetGitVersion)
# get_git_version(VERSION_VARIABLE_PREFIX [<additional args for git_describe>])
#
# Following variables are set by get_git_version:
# VERSION_VARIABLE_PREFIX_MAJOR, VERSION_VARIABLE_PREFIX_MINOR,
# VERSION_VARIABLE_PREFIX_PATCH, VERSION_VARIABLE_PREFIX_EXTRA,
# VERSION_VARIABLE_PREFIX
#
# "THE BEER-WARE LICENSE" (Revision 42):
# <cptiglo@treefish.org> wrote this file.  As long as you retain this notice
# you can do whatever you want with this stuff. If we meet some day, and you
# think this stuff is worth it, you can buy me a beer in return.
# __________________________________________________________________________ __ _

function(get_git_version _gitversionprefix)
    include(GetGitRevisionDescription)
    git_describe(GIT_DESCRIPTION ${ARGN})

    string(REGEX REPLACE "^[^0-9]*([0-9]+)\\..*" "\\1" VERSION_MAJOR "${GIT_DESCRIPTION}")
    string(REGEX REPLACE "^[^0-9]*[0-9]+\\.([0-9]+).*" "\\1" VERSION_MINOR "${GIT_DESCRIPTION}")
    string(REGEX REPLACE "^[^0-9]*[0-9]+\\.[0-9]+\\.([0-9]+).*" "\\1" VERSION_PATCH "${GIT_DESCRIPTION}")
    string(REGEX REPLACE "^[^0-9]*[0-9]+\\.[0-9]+\\.[0-9]+-(.*)" "\\1" VERSION_EXTRA "${GIT_DESCRIPTION}")
    string(REGEX REPLACE "([^-]*-g)" "r\\1" VERSION_EXTRA "${VERSION_EXTRA}")
    string(REGEX REPLACE "-" "." VERSION_EXTRA "${VERSION_EXTRA}")

    set(${_gitversionprefix}_MAJOR "${VERSION_MAJOR}" PARENT_SCOPE)
    set(${_gitversionprefix}_MINOR "${VERSION_MINOR}" PARENT_SCOPE)
    set(${_gitversionprefix}_PATCH "${VERSION_PATCH}" PARENT_SCOPE)
    set(${_gitversionprefix}_EXTRA "${VERSION_EXTRA}" PARENT_SCOPE)

    set(${_gitversionprefix}
	"${VERSION_MAJOR}.${VERSION_MINOR}.${VERSION_PATCH}-${VERSION_EXTRA}" PARENT_SCOPE)
endfunction()