ability to specify field list (for Ogg/Flac), as well as specify field contents (Debian: #655078)

It allows to call `cuetag` like so:

    cuetag Björk-Volta.cue *.ogg ARTIST ALBUM TITLE YEAR=2007 GENRE=electronic TRACKNUMBER

 which accomplishes two things:

  1. it pre-selects the fields and specifies their order;

  2. it hardcodes two fields to specific values for all tracks.

 Since the field list is hardcoded for MP3, any fields specified on
 the command line are effectively ignored. This could probably be
 implemented better, but I do not care about MP3 at all.

Bug-Debian: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=655078
From: martin f krafft <madduck@debian.org>
Author: Dmitry Smirnov <onlyjob@member.fsf.org>

src/tools/cuetag.sh

@@ -27,6 +27,10 @@ usage()
 # for FLAC and Ogg Vorbis files
 vorbis()
 {
+	trackno=$1; shift
+	file="$1"; shift
+	fields="$@"
+
 	# FLAC tagging
 	# --remove-vc-all overwrites existing comments
 	METAFLAC="metaflac --remove-all-tags --import-tags-from=-"
@@ -40,7 +44,7 @@ vorbis()
 	# TODO: this also outputs to stdout
 	TXTFILE="tee"
 
-	case "$2" in
+	case "$file" in
 	*.[Ff][Ll][Aa][Cc])
 		VORBISTAG=$METAFLAC
 		;;
@@ -55,8 +59,9 @@ vorbis()
 	# space seperated list of recomended stardard field names
 	# see http://www.xiph.org/ogg/vorbis/doc/v-comment.html
 	# TRACKTOTAL is not in the Xiph recomendation, but is in common use
-	
-	fields='TITLE VERSION ALBUM TRACKNUMBER TRACKTOTAL ARTIST PERFORMER COPYRIGHT LICENSE ORGANIZATION DESCRIPTION GENRE DATE LOCATION CONTACT ISRC'
+
+	[ -n "$fields" ] ||
+		fields='TITLE VERSION ALBUM TRACKNUMBER TRACKTOTAL ARTIST PERFORMER COPYRIGHT LICENSE ORGANIZATION DESCRIPTION GENRE DATE LOCATION CONTACT ISRC'
 
 	# fields' corresponding cueprint conversion characters
 	# seperate alternates with a space
@@ -79,16 +84,21 @@ vorbis()
 	ISRC='%i %u'
 
 	(for field in $fields; do
-		value=""
-		for conv in $(eval echo \$$field); do
-			value=$($CUEPRINT -n $1 -t "$conv\n" "$cue_file")
+		case "$field" in
+			(*=*) echo "$field";;
+			(*)
+				value=""
+				for conv in $(eval echo \$$field); do
+					value=$($CUEPRINT -n $trackno -t "$conv\n" "$cue_file")
 
-			if [ -n "$value" ]; then
-				echo "$field=$value"
-				break
-			fi
-		done
-	done) | $VORBISTAG "$2"
+					if [ -n "$value" ]; then
+						echo "$field=$value"
+						break
+					fi
+				done
+				;;
+		esac
+	done) | $VORBISTAG "$file"
 }
 
 id3()
@@ -117,14 +127,19 @@ id3()
 	TRACKNUMBER='%n'
 
 	for field in $fields; do
-		value=""
-		for conv in $(eval echo \$$field); do
-			value=$($CUEPRINT -n $1 -t "$conv\n" "$cue_file")
+		case "$field" in
+			*=*) value="${field#*=}";;
+			*)
+				value=""
+				for conv in $(eval echo \$$field); do
+					value=$($CUEPRINT -n $1 -t "$conv\n" "$cue_file")
 
-			if [ -n "$value" ]; then
-				break
-			fi
-		done
+					if [ -n "$value" ]; then
+						break
+					fi
+				done
+				;;
+		esac
 
 		if [ -n "$value" ]; then
 			case $field in
@@ -167,6 +182,15 @@ main()
 	ntrack=$(cueprint -d '%N' "$cue_file")
 	trackno=1
 
+	FILES= FIELDS=
+	for arg in "$@"; do
+		case "$arg" in
+			*.*) FILES="$FILES $arg";;
+			*) FIELDS="$FIELDS $arg";;
+		esac
+	done
+
+	set -- $FILES
 	if [ $# -ne $ntrack ]; then
 		echo "warning: number of files does not match number of tracks"
 	fi
@@ -174,13 +198,13 @@ main()
 	for file in "$@"; do
 		case $file in
 		*.[Ff][Ll][Aa][Cc])
-			vorbis $trackno "$file"
+			vorbis $trackno "$file" $FIELDS
 			;;
 		*.[Oo][Gg][Gg])
-			vorbis $trackno "$file"
+			vorbis $trackno "$file" $FIELDS
 			;;
 		*.[Mm][Pp]3)
-			id3 $trackno "$file"
+			id3 $trackno "$file" $FIELDS
 			;;
 		*.[Tt][Xx][Tt])
 			vorbis $trackno "$file"