#!/bin/sh
 

 # check for git short hash

 if ! test "$revision"; then

     if (cd "$1" && grep git RELEASE 2> /dev/null >/dev/null) ; then
         revision=$(cd "$1" && git describe --tags --match N 2> /dev/null)
     else
         revision=$(cd "$1" && git describe --tags --always 2> /dev/null)
     fi

 fi
 

 # Shallow Git clones (--depth) do not have the N tag:
 # use 'git-YYYY-MM-DD-hhhhhhh'.
 test "$revision" || revision=$(cd "$1" &&
   git log -1 --pretty=format:"git-%cd-%h" --date=short 2> /dev/null)
 
 # Snapshots from gitweb are in a directory called ffmpeg-hhhhhhh or
 # ffmpeg-HEAD-hhhhhhh.
 if [ -z "$revision" ]; then
   srcdir=$(cd "$1" && pwd)
   case "$srcdir" in
     */ffmpeg-[0-9a-f][0-9a-f][0-9a-f][0-9a-f][0-9a-f][0-9a-f][0-9a-f])
       git_hash="${srcdir##*-}";;
     */ffmpeg-HEAD-[0-9a-f][0-9a-f][0-9a-f][0-9a-f][0-9a-f][0-9a-f][0-9a-f])
       git_hash="${srcdir##*-}";;
   esac
 fi
 

 # no revision number found

 test "$revision" || revision=$(cd "$1" && cat RELEASE 2> /dev/null)

 # Append the Git hash if we have one
 test "$revision" && test "$git_hash" && revision="$revision-$git_hash"
 

 # releases extract the version number from the VERSION file

 version=$(cd "$1" && cat VERSION 2> /dev/null)

 test "$version" || version=$revision

 test -n "$3" && version=$version-$3
 

 if [ -z "$2" ]; then
     echo "$version"
     exit
 fi
 

 NEW_REVISION="#define FFMPEG_VERSION \"$version\""

 OLD_REVISION=$(cat version.h 2> /dev/null)

 
 # Update version.h only on revision changes to avoid spurious rebuilds
 if test "$NEW_REVISION" != "$OLD_REVISION"; then

     echo "$NEW_REVISION" > "$2"

 fi