X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ian/git?p=chiark-utils.git;a=blobdiff_plain;f=scripts%2Fexpire-iso8601;h=530c48c170bf4adb8d1ab1cab5d8a01526a53a8f;hp=7cb274e607991354cf88b890b108054c5c9ed9c7;hb=a7cf1cb556e8f28457464f4729f56dad1e6536a9;hpb=21db76d0effbbe0e0b84cdcf230d46fd8dc36017

diff --git a/scripts/expire-iso8601 b/scripts/expire-iso8601
index 7cb274e..530c48c 100755
--- a/scripts/expire-iso8601
+++ b/scripts/expire-iso8601
@@ -28,6 +28,23 @@ exit status:
 END
 			}
 
+# Copyright 2006 Ian Jackson <ian@chiark.greenend.org.uk>
+#
+# This script and its documentation (if any) are free software; you
+# can redistribute it and/or modify them under the terms of the GNU
+# General Public License as published by the Free Software Foundation;
+# either version 3, or (at your option) any later version.
+# 
+# chiark-named-conf and its manpage are distributed in the hope that
+# it will be useful, but WITHOUT ANY WARRANTY; without even the
+# implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
+# PURPOSE.  See the GNU General Public License for more details.
+# 
+# You should have received a copy of the GNU General Public License along
+# with this program; if not, consult the Free Software Foundation's
+# website at www.fsf.org, or the GNU Project website at www.gnu.org.
+
+
 trap 'exit 16' 0
 badusage () { echo >&2 "bad usage: $*"; usage >&2; trap '' 0; exit 8; }
 
@@ -106,7 +123,8 @@ done
 
 # We process each minimum/extent pair, to have it select a bunch of
 # versions to keep.  We annotate entries in $l: if we are keeping
-# an entry we prepend a colon.
+# an entry we prepend a colon; temporarily, if we are keeping an entry
+# because of this particular minimum/extent, we prepend a comma.
 
 # For each minimum/extent pair we look at the list from most recent
 # to least recent,
@@ -123,27 +141,49 @@ END
 )
 
 for ni in "$@"; do
-	min=$(( ${ni#*x} * $unit - $slop ))
 	wantcount=${ni%x*}
 
-	ls=''
+	div=1
+
+	while true; do
+		min=$(( (${ni#*x} * $unit) / $div - $slop ))
+
+		ls=''
+		lnew=''
+		skipped=0
+		for ce in $l; do
+			cn=${ce#*/}; cl=${ce%%/*}
+			cs=${cl#,}; cs=${cs#:}
+			case $cl in ,*)	ls=$cs; continue;; esac
+			if [ $wantcount != 0 ]; then
+				if ! [ "$ls" ] || \
+				   [ $(( $ls - $cs )) -ge $min ]; then
+					echo "keep (for $ni) $cn"
+					ce=,$ce
+					ls=$cs
+					wantcount=$(( $wantcount - 1 ))
+				else
+					skipped=$(( $skipped+1 ))
+				fi
+			fi
+			lnew="$lnew $ce"
+		done
+		l=$lnew
+
+		if [ $wantcount = 0 ]; then break; fi
+		printf "%s" "insufficient (for $ni) by $wantcount"
+		if [ $skipped = 0 ]; then echo; break; fi
+		div=$(( $div * 2 ))
+		echo " shortening interval ${div}x"
+	done
+
+	# s/([,:]+).*/:\1/g
 	lnew=''
 	for ce in $l; do
-		cn=${ce#*/}; cl=${ce%%/*}; cs=${cl#:}
-		if [ $wantcount != 0 ]; then
-			if ! [ "$ls" ] || \
-			   [ $(( $ls - $cs )) -ge $min ]; then
-				echo "keep (for $ni) $cn"
-				ls=$cs
-				ce=:$cs/$cn
-				wantcount=$(( $wantcount - 1 ))
-			fi
-		fi
+		case $ce in ,*) ce=:${ce#,};; esac
+		case $ce in ::*) ce=${ce#:};; esac
 		lnew="$lnew $ce"
 	done
-	if [ $wantcount != 0 ];then
-		echo "insufficient (for $ni) by $wantcount"
-	fi
 	l=$lnew
 done