altoslib: Add preferences for saving/restoring multiple flight states

Signed-off-by: Keith Packard <keithp@keithp.com>

diff --git a/altoslib/AltosPreferences.java b/altoslib/AltosPreferences.java
index 2fad96fd81e1000343582492ac3c0f69691f725b..cdff93f6ed80bf2286d5b570bf300e25c058c4a1 100644 (file)
--- a/altoslib/AltosPreferences.java
+++ b/altoslib/AltosPreferences.java
@@ -19,6 +19,7 @@ package org.altusmetrum.altoslib_7;
 
 import java.io.*;
 import java.util.*;
+import java.text.*;
 
 public class AltosPreferences {
        public static AltosPreferencesBackend backend = null;
@@ -42,7 +43,9 @@ public class AltosPreferences {
        public final static String logfilePreferenceFormat = "LOGFILE-%d";
 
        /* state preference name */
+       public final static String statePreferenceHead = "STATE-";
        public final static String statePreferenceFormat = "STATE-%d";
+       public final static String statePreferenceLatest = "STATE-LATEST";
 
        /* voice preference name */
        public final static String voicePreference = "VOICE";
@@ -360,12 +363,43 @@ public class AltosPreferences {
 
                        synchronized(backend) {
                                backend.putBytes(String.format(statePreferenceFormat, serial), bytes);
+                               backend.putInt(statePreferenceLatest, serial);
                                flush_preferences();
                        }
                } catch (IOException ie) {
                }
        }
 
+       public static ArrayList<Integer> list_states() {
+               String[]                keys = backend.keys();
+               ArrayList<Integer>      states = new ArrayList<Integer>();
+
+               for (String key : keys) {
+                       if (key.startsWith(statePreferenceHead)) {
+                               try {
+                                       int serial = AltosParse.parse_int(key.substring(statePreferenceHead.length()));
+                                       states.add(serial);
+                               } catch (ParseException pe) {
+                               }
+                       }
+               }
+               return states;
+       }
+
+       public static void remove_state(int serial) {
+               synchronized(backend) {
+                       backend.remove(String.format(statePreferenceFormat, serial));
+               }
+       }
+
+       public static int latest_state() {
+               int     latest = 0;
+               synchronized (backend) {
+                       latest = backend.getInt(statePreferenceLatest, 0);
+               }
+               return latest;
+       }
+
        public static AltosSavedState state(int serial) {
                byte[] bytes = null;