Binary Saves

This replaces the Base64 encoded save format with a new binary one.
It's tiny. It's hard to modify. It shouldn't get in the way much -
you can break binary compatibility before release if you want, but
to preserve it, all you need to do is:

* Not remove properties from the save format
* Add new properties AFTER all existing ones
* Give every property the [Order] decorator/attribute

You don't need to touch the save/load code unless you're adding a
type it doesn't recognise.

Also, the SaveSystem provides the ReadSave() and WriteSave()
functions now, so other components of TimeHACK don't need to care
about the actual save format.

1 files changed, 327 insertions, 43 deletions

diff --git a/TimeHACK.Engine/SaveSystem.cs b/TimeHACK.Engine/SaveSystem.cs
index 81aa322..cda4464 100644
--- a/TimeHACK.Engine/SaveSystem.cs
+++ b/TimeHACK.Engine/SaveSystem.cs
@@ -1,4 +1,10 @@
-using System;
+// Define BINARY_SAVE before release so the player has
+// to put some effort into cheating ;)
+// During development, leave it undefined to use the
+// easily modifiable JSON serialised format
+//#define BINARY_SAVE
+
+using System;
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
@@ -7,6 +13,7 @@ using System.Threading.Tasks;
 using Newtonsoft.Json;
 using System.Diagnostics;
 using System.Windows.Forms;
+using System.Runtime.CompilerServices;
 
 namespace TimeHACK.Engine
 {
@@ -19,6 +26,11 @@ namespace TimeHACK.Engine
 
         public static Theme currentTheme { get; set; }
 
+#if BINARY_SAVE
+        private static readonly byte[] magic = Encoding.UTF8.GetBytes("THSv");
+        private static readonly IOrderedEnumerable<System.Reflection.PropertyInfo> properties = typeof(Save).GetProperties().OrderBy(p => (p.GetCustomAttributes(typeof(OrderAttribute), false).SingleOrDefault() as OrderAttribute).Order);
+#endif
+
         public static string GameDirectory
         {
             get
@@ -102,36 +114,6 @@ namespace TimeHACK.Engine
             }
         }
 
-        public static bool LoadSave()
-        {
-            try
-            {
-                // ON A FINAL RELEASE USE THE "FINAL RELEASE THINGS"
-                #region Final Release Things
-                //Read base64 string from file
-                //string b64 = File.ReadAllText(Path.Combine(ProfileDirectory, ProfileFile));
-                //Get Unicode byte array
-                //byte[] bytes = Convert.FromBase64String(b64);
-                //Decode the Unicode
-                //string json = Encoding.UTF8.GetString(bytes);
-                //Deserialize save object.
-                #endregion
-                // USE THE THINGS IN THE "DEVELOPER THINGS" FOR A DEVELOPMENT RELEASE
-                #region Developer Things
-                string json = File.ReadAllText(Path.Combine(ProfileDirectory, ProfileFile));
-                #endregion
-                CurrentSave = JsonConvert.DeserializeObject<Save>(json);
-                
-            } catch
-            {
-                MessageBox.Show("WARNING! It looks like this save is corrupt!");
-                MessageBox.Show("We will now open the Save troubleshooter");
-
-                troubleshooter.ShowDialog();
-            }
-            return true;
-        }
-
         public static void NewGame()
         {        
             var save = new Save();
@@ -247,21 +229,297 @@ namespace TimeHACK.Engine
             File.WriteAllText(Path.Combine(directory, "_data.info"), toWrite);
         }
 
+#if BINARY_SAVE
+        // Be careful with this... it trusts that the calling code has already checked
+        // that T can be written by BinaryWriter.
+        // No generics, because that'd be near-impossible to read back.
+        private static void WriteList<T>(BinaryWriter write, List<T> list)
+        {
+            if (list == null)
+                write.Write(0);
+            else
+            {
+                write.Write(list.Count);
+                foreach (T obj in list)
+                    ((dynamic)write).Write(obj);
+            }
+        }
+
+        private static List<T> ReadList<T>(BinaryReader read, string reader)
+        {
+            int count = read.ReadInt32();
+            var ret = new List<T>(count);
+            var function = typeof(BinaryReader).GetMethod(reader);
+            for (int i = 0; i < count; i++)
+                ret.Add((T) function.Invoke(read, new object[] { }));
+            return ret;
+        }
+
+        private static void WriteBitfield(Stream fobj, IEnumerable<bool> bools)
+        {
+            sbyte bit = 7;
+            int cur = 0;
+            var bitfields = new byte[bools.Count() / 8 + 1];
+            foreach (bool mybool in bools)
+            {
+                if (mybool)
+                    bitfields[cur] |= (byte) (1 << bit);
+                bit--;
+                if (bit < 0)
+                {
+                    bit = 7;
+                    cur++;
+                }
+            }
+            fobj.Write(bitfields, 0, bitfields.Length);
+        }
+
+        private static List<bool> ReadBitfield(Stream fobj, int count)
+        {
+            sbyte bit = 7;
+            int cur = 0;
+            var bitfields = new byte[count / 8 + 1];
+            var bools = new List<bool>(count);
+            byte val = (byte) fobj.ReadByte();
+            fobj.Read(bitfields, 0, bitfields.Length);
+            for (int i = 0; i < count; i++)
+            {
+                bools.Add(((val >> bit) & 1) == 1);
+                bit--;
+                if (bit < 0)
+                {
+                    bit = 7;
+                    cur++;
+                }
+            }
+            return bools;
+        }
+#endif
+
+        public static Save ReadSave(string fname)
+        {
+#if BINARY_SAVE
+            using (var fobj = File.OpenRead(fname))
+            {
+                var save = new Save();
+                var header = new byte[magic.Length];
+                var read = new BinaryReader(fobj);
+                fobj.Read(header, 0, magic.Length);
+                if (!magic.SequenceEqual(header))
+                    throw new InvalidDataException("This is not a TimeHACK binary save");
+                int numprops = read.ReadInt32();
+                var bools = new List<System.Reflection.PropertyInfo>();
+                // Holy code duplication, Batman.
+                // If you know a better way to get C# to do this, I'm all ears.
+                foreach (var property in properties.Take(numprops))
+                {
+                    if (property.PropertyType == typeof(string))
+                        property.SetValue(save, read.ReadString());
+                    else if (property.PropertyType == typeof(int))
+                        property.SetValue(save, read.ReadInt32());
+                    else if (property.PropertyType == typeof(uint))
+                        property.SetValue(save, read.ReadUInt32());
+                    else if (property.PropertyType == typeof(long))
+                        property.SetValue(save, read.ReadInt64());
+                    else if (property.PropertyType == typeof(ulong))
+                        property.SetValue(save, read.ReadUInt64());
+                    else if (property.PropertyType == typeof(short))
+                        property.SetValue(save, read.ReadInt16());
+                    else if (property.PropertyType == typeof(ushort))
+                        property.SetValue(save, read.ReadUInt16());
+                    else if (property.PropertyType == typeof(byte))
+                        property.SetValue(save, read.ReadByte());
+                    else if (property.PropertyType == typeof(sbyte))
+                        property.SetValue(save, read.ReadSByte());
+                    else if (property.PropertyType == typeof(char))
+                        property.SetValue(save, read.ReadChar());
+                    else if (property.PropertyType == typeof(float))
+                        property.SetValue(save, read.ReadSingle());
+                    else if (property.PropertyType == typeof(double))
+                        property.SetValue(save, read.ReadDouble());
+                    else if (property.PropertyType == typeof(decimal))
+                        property.SetValue(save, read.ReadDecimal());
+
+                    else if (property.PropertyType == typeof(List<string>))
+                        property.SetValue(save, ReadList<string>(read, "ReadString"));
+                    else if (property.PropertyType == typeof(List<int>))
+                        property.SetValue(save, ReadList<string>(read, "ReadInt32"));
+                    else if (property.PropertyType == typeof(List<uint>))
+                        property.SetValue(save, ReadList<string>(read, "ReadUInt32"));
+                    else if (property.PropertyType == typeof(List<long>))
+                        property.SetValue(save, ReadList<string>(read, "ReadInt64"));
+                    else if (property.PropertyType == typeof(List<ulong>))
+                        property.SetValue(save, ReadList<string>(read, "ReadUInt64"));
+                    else if (property.PropertyType == typeof(List<short>))
+                        property.SetValue(save, ReadList<string>(read, "ReadInt16"));
+                    else if (property.PropertyType == typeof(List<ushort>))
+                        property.SetValue(save, ReadList<string>(read, "ReadUInt16"));
+                    else if (property.PropertyType == typeof(List<byte>))
+                        property.SetValue(save, ReadList<string>(read, "ReadByte"));
+                    else if (property.PropertyType == typeof(List<sbyte>))
+                        property.SetValue(save, ReadList<string>(read, "ReadSByte"));
+                    else if (property.PropertyType == typeof(List<char>))
+                        property.SetValue(save, ReadList<string>(read, "ReadChar"));
+                    else if (property.PropertyType == typeof(List<float>))
+                        property.SetValue(save, ReadList<string>(read, "ReadSingle"));
+                    else if (property.PropertyType == typeof(List<double>))
+                        property.SetValue(save, ReadList<string>(read, "ReadDouble"));
+                    else if (property.PropertyType == typeof(List<decimal>))
+                        property.SetValue(save, ReadList<string>(read, "ReadDecimal"));
+
+                    // Remember to read this boolean from the bitfield at the end.
+                    else if (property.PropertyType == typeof(bool))
+                        bools.Add(property);
+
+                    else if (property.PropertyType == typeof(List<bool>))
+                        property.SetValue(save, ReadBitfield(fobj, read.ReadInt32()));
+
+                    // RIP
+                    else
+                        throw new InvalidDataException("There is no deserialisation method specified for " + property.PropertyType.ToString());
+                }
+
+                // Let's read the ultra tiny bitfield.
+                var loaded = ReadBitfield(fobj, bools.Count);
+                foreach (var item in bools.Zip(loaded, (p, b) => new { Property = p, Value = b }))
+                    item.Property.SetValue(save, item.Value);
+
+                return save;
+            }
+#else
+            return JsonConvert.DeserializeObject<Save>(File.ReadAllText(fname));
+#endif
+        }
+
+        public static void WriteSave(string fname, Save save)
+        {
+#if BINARY_SAVE
+            using (var fobj = File.OpenWrite(fname))
+            {
+                var write = new BinaryWriter(fobj);
+                var bools = new List<bool>();
+                fobj.Write(magic, 0, magic.Length);
+                write.Write(properties.Count()); // The number of properties basically acts as the version number.
+
+                foreach (var property in properties)
+                {
+                    if (property == null)
+                        continue;
+
+                    // Types that can be written by BinaryWriter, except booleans.
+                    if (property.PropertyType == typeof(string))
+                    {
+                        var val = property.GetValue(save) as string;
+                        if (val == null)
+                            write.Write("");
+                        else
+                            write.Write(val);
+                    }
+                    else if (property.PropertyType == typeof(int))
+                        write.Write((int) property.GetValue(save));
+                    else if (property.PropertyType == typeof(uint))
+                        write.Write((uint) property.GetValue(save));
+                    else if (property.PropertyType == typeof(long))
+                        write.Write((long) property.GetValue(save));
+                    else if (property.PropertyType == typeof(ulong))
+                        write.Write((ulong) property.GetValue(save));
+                    else if (property.PropertyType == typeof(short))
+                        write.Write((short) property.GetValue(save));
+                    else if (property.PropertyType == typeof(ushort))
+                        write.Write((ushort) property.GetValue(save));
+                    else if (property.PropertyType == typeof(byte))
+                        write.Write((byte) property.GetValue(save));
+                    else if (property.PropertyType == typeof(sbyte))
+                        write.Write((sbyte) property.GetValue(save));
+                    else if (property.PropertyType == typeof(char))
+                        write.Write((char) property.GetValue(save));
+                    else if (property.PropertyType == typeof(float))
+                        write.Write((float) property.GetValue(save));
+                    else if (property.PropertyType == typeof(double))
+                        write.Write((double) property.GetValue(save));
+                    else if (property.PropertyType == typeof(decimal))
+                        write.Write((double) property.GetValue(save));
+
+                    // ... and their lists.
+                    else if (property.PropertyType == typeof(List<string>))
+                        WriteList(write, property.GetValue(save) as List<string>);
+                    else if (property.PropertyType == typeof(List<int>))
+                        WriteList(write, property.GetValue(save) as List<int>);
+                    else if (property.PropertyType == typeof(List<uint>))
+                        WriteList(write, property.GetValue(save) as List<uint>);
+                    else if (property.PropertyType == typeof(List<long>))
+                        WriteList(write, property.GetValue(save) as List<long>);
+                    else if (property.PropertyType == typeof(List<ulong>))
+                        WriteList(write, property.GetValue(save) as List<ulong>);
+                    else if (property.PropertyType == typeof(List<short>))
+                        WriteList(write, property.GetValue(save) as List<short>);
+                    else if (property.PropertyType == typeof(List<ushort>))
+                        WriteList(write, property.GetValue(save) as List<ushort>);
+                    else if (property.PropertyType == typeof(List<byte>))
+                        WriteList(write, property.GetValue(save) as List<byte>);
+                    else if (property.PropertyType == typeof(List<sbyte>))
+                        WriteList(write, property.GetValue(save) as List<sbyte>);
+                    else if (property.PropertyType == typeof(List<char>))
+                        WriteList(write, property.GetValue(save) as List<char>);
+                    else if (property.PropertyType == typeof(List<float>))
+                        WriteList(write, property.GetValue(save) as List<float>);
+                    else if (property.PropertyType == typeof(List<double>))
+                        WriteList(write, property.GetValue(save) as List<double>);
+                    else if (property.PropertyType == typeof(List<decimal>))
+                        WriteList(write, property.GetValue(save) as List<decimal>);
+
+                    // Booleans - they go in the bitfield at the end.
+                    else if (property.PropertyType == typeof(bool))
+                        bools.Add((bool) property.GetValue(save));
+
+                    // List of booleans - it gets its own bitfield.
+                    else if (property.PropertyType == typeof(List<bool>))
+                    {
+                        var val = property.GetValue(save) as List<bool>;
+                        if (val == null)
+                            write.Write(0);
+                        else
+                        {
+                            write.Write(val.Count());
+                            WriteBitfield(fobj, val);
+                        }
+                    }
+
+                    // Now what?
+                    else
+                        throw new InvalidDataException("There is no serialisation method specified for " + property.PropertyType.ToString());
+                }
+
+                // In order to save space, we store bools in a bitfield at the end.
+                // One byte can store 8 bools, saving a whopping 7 bytes which can then be used for
+                // extremely short text documents or something.
+                WriteBitfield(fobj, bools);
+            }
+#else
+            // Serialize the save to JSON.
+            File.WriteAllText(fname, JsonConvert.SerializeObject(save, Formatting.Indented));
+#endif
+        }
 
         public static void SaveGame()
         {
-            //Serialize the save to JSON.
-            string json = JsonConvert.SerializeObject(CurrentSave, Formatting.Indented);
-
-            // ADD THE TWO LINES OF CODE BELOW ON A FINAL RELEASE
-            //Get JSON bytes (Unicode format).
-            //var bytes = Encoding.UTF8.GetBytes(json);
-            //Encode the array into Base64.
-            //string b64 = Convert.ToBase64String(bytes);
-            //Write to disk.
-
-            // CHANGE THE "JSON" TO "B64" ON A FINAL RELEASE!
-            File.WriteAllText(Path.Combine(ProfileDirectory, ProfileFile), json);
+            WriteSave(Path.Combine(ProfileDirectory, ProfileFile), CurrentSave);
+        }
+
+        public static bool LoadSave()
+        {
+            string savefile = Path.Combine(ProfileDirectory, ProfileFile);
+            try
+            {
+                CurrentSave = ReadSave(savefile);
+            }
+            catch
+            {
+                MessageBox.Show("WARNING! It looks like this save is corrupt! We will now open the Save troubleshooter");
+
+                troubleshooter.ShowDialog();
+            }
+            return true;
         }
 
         public static byte[] GetAchievements()
@@ -295,14 +553,40 @@ namespace TimeHACK.Engine
         }
     }
 
+
+    // This lets us preserve the order of properties.
+    // Thanks to "ghord" from StackOverflow.
+    public sealed class OrderAttribute : Attribute
+    {
+        private readonly int order_;
+        public OrderAttribute([CallerLineNumber]int order = 0)
+        {
+            order_ = order;
+        }
+        public int Order { get { return order_; } }
+    }
+
     public class Save
     {
+        // To maintain binary save compatibility,
+        // add all new properties to the end and don't remove any.
+        // Also, every property needs an "Order" attribute.
+
+        [Order]
         public string Username { get; set; }
 
+        [Order]
         public string CurrentOS { get; set; }
+
         // public Dictionary<string, bool> InstalledPrograms { get; set; } InstallProgram is no longer needed... we have that data in the FileSystem
+
+        [Order]
         public List<string> ExperiencedStories { get; set; }
+
+        [Order]
         public bool FTime95 { get; set; }
+
+        [Order]
         public string ThemeName { get; set; }
     }