Add version compare function to setup/index.txt

Okay Ivan, you can "I told you so" now.  I didn't see any major gotchas
to changing the version and was SURE there'd be no reason to write the
convoluted comparison function until after everything was nicely redone
and restructured and whatnot.  Fortunately I only need it in the main
script for now, and will hopefully very soon be able to just load it
from a common function file and use it where needed.

I still don't regret doing it, but all the work I had to do in order to
make sure I didn't screw it up (or rather that I fixed it after screwing
it up) are totally on me.

scripts/a2server-3-sharing.txt

@@ -49,7 +49,7 @@ debianName=$(lsb_release -cs)
 if [[ -f /usr/local/etc/A2SERVER-version ]]; then
 	read a2sVersion </usr/local/etc/A2SERVER-version
 fi
-if [[ "$a2sVersion" != *.*.* || "$a2sVersion" -lt 101 ]]; then
+if [[ "$a2sVersion" != *.*.* && "$a2sVersion" -lt 101 ]]; then
 	echo "A2SERVER: Installing Netatalk (this will take a while)..."
 	# stop Netatalk and samba if running (during upgrade)
 	if [[ $(ps --no-headers -C afpd) ]]; then

setup/index.txt

@@ -53,6 +53,66 @@ fi
 echo "A2SERVER version available: $a2serverVersion"
 echo "A2SERVER version installed: ${installedVersion:=None}"
 
+function a2sCmpInstalled() {
+	local iMajor iMinor iRev
+	local cMajor cMinor cRev
+
+	[[ -z "$installedVersion" ]] && return 0 # No, not installed
+	[[ -z "$1" ]] && return 1
+	iMajor=${installedVersion%%.*}
+	iMinor=${installedVersion#*.}
+	iMinor=${iMinor%%.*}
+	iRev=${installedVersion##*.}
+	cMajor=${2%%.*}
+	cMinor=${2#*.}
+	cMinor=${cMinor%%.*}
+	cRev=${2##*.}
+
+	case "$1" in
+		lt|le)
+			if [[ "$iMajor" -lt "$cMajor" ]]; then
+				return 0
+			elif [[ "$iMajor" -eq "$cMajor" ]]; then
+				if [[ "$iMinor" -lt "$cMinor" ]]; then
+					return 0
+				elif [[ "$iMinor" -eq "$cMinor" ]]; then
+					if [[ "$iRev" -le "$cRev" ]]; then
+						if [[ "$1" == "le" || "$iRev" -lt "$cRev" ]]; then
+							return 0
+						fi
+					fi
+				fi
+			fi
+			;;
+		gt|ge)
+			if [[ "$iMajor" -gt "$cMajor" ]]; then
+				return 0
+			elif [[ "$iMajor" -eq "$cMajor" ]]; then
+				if [[ "$iMinor" -gt "$cMinor" ]]; then
+					return 0
+				elif [[ "$iMinor" -eq "$cMinor" ]]; then
+					if [[ "$iRev" -ge "$cRev" ]]; then
+						if [[ "$1" == "ge" || "$iRev" -gt "$cRev" ]]; then
+							return 0
+						fi
+					fi
+				fi
+			fi
+			;;
+		eq)
+			if [[ "$iMajor" -eq "$cMajor" ]]; then
+				if [[ "$iMinor" -eq "$cMinor" ]]; then
+					if [[ "$iRev" -eq "$cRev" ]]; then
+						return 0
+					fi
+				fi
+			fi
+			;;
+	esac
+
+	return 1
+}
+
 echo
 [[ $scriptURL != *"ivanx.com"* && $scriptURL != *"raw.githubusercontent.com/RasppleII/a2server"* ]] && echo "Using script URL: $scriptURL"
 [[ $binaryURL != *"ivanx.com"* ]] && echo "Using binary URL: $binaryURL"
@@ -132,7 +192,7 @@ if [[ $updateRasppleII ]]; then
 	fi
 fi
 
-if [[ -f /usr/local/etc/A2SERVER-version && $(head -c 3 /usr/local/etc/A2SERVER-version) -lt 110 ]]; then
+if a2sCmpInstalled lt 1.1.0; then
 	echo
 	echo "WARNING: The current A2SERVER installer scripts haven't been tested for"
 	echo "updating the earlier version of A2SERVER that you have. A fresh install"
@@ -143,7 +203,7 @@ fi
 a2server_update=0
 doSetup=1
 
-if [[ -f /usr/local/etc/A2SERVER-version && $(head -c 3 /usr/local/etc/A2SERVER-version) -lt 150 ]]; then
+if a2sCmpInstalled lt 1.5.0; then
 	a2server_update=1
 fi