Files
OpenMaidEngine/engine/Age.Engine/Persistence/NativeNumberedSaveCodec.cs
2026-07-24 18:43:21 -04:00

296 lines
13 KiB
C#

using System.Buffers.Binary;
using System.Text;
namespace Age.Engine.Persistence;
public sealed record NativeSavedScriptFrame(
int ParentContext,
uint ScriptId,
IReadOnlyList<int> ReturnIndices,
int ResumeIndex,
int CallTargetIndex);
public sealed record NativeSavedGfxObject(long Handle, byte[] Record);
public sealed record NativeNumberedSaveState(
int SavedFrameOwner,
int BgmTrackId,
IReadOnlyList<int> SoundEffectResourceIds,
byte[] ResourceRecords,
byte[] SurfaceRecords,
IReadOnlyList<NativeSavedScriptFrame> Frames,
IReadOnlyList<int> IntegerGlobals,
IReadOnlyList<int> FloatGlobals,
IReadOnlyList<string> StringGlobals,
IReadOnlyList<int> PointerGlobals,
IReadOnlyList<int> PointerStrings,
IReadOnlyList<int> LocalPointerScratch,
IReadOnlyList<NativeSavedGfxObject> GfxObjects,
long RangeTransformFirst,
int RangeTransformCount,
byte[] RangeTransformRecord)
{
public const int SoundEffectChannelCount = 10;
public const int ResourceRecordsSize = 300 * 4;
public const int SurfaceRecordsSize = 20_000;
public const int GfxRecordSize = 0x2d4;
}
/// <summary>AGE SaveVersion1=3 numbered-save logical payload.</summary>
public static class NativeNumberedSaveCodec
{
private const int FixedPrefixSize = 0x5304;
private const int FrameSize = 0x414;
private const int FixedSuffixSize = 0x414;
private const int FrameReturnCapacity = 256;
private const int GfxAllocationDwords = 0x2d8;
private const int GfxConstantDwords = 0x2e1;
private static readonly Encoding NativeEncoding = CreateNativeEncoding();
public static byte[] Encode(NativeNumberedSaveState state)
{
ArgumentNullException.ThrowIfNull(state);
ValidateState(state);
int cutoff = state.Frames.Count - 1;
byte[] strings = EncodeStrings(state.StringGlobals);
int stringDwords = strings.Length / 4;
int bankDwords = checked(
state.IntegerGlobals.Count + state.FloatGlobals.Count + state.StringGlobals.Count
+ state.PointerGlobals.Count + state.PointerStrings.Count + state.LocalPointerScratch.Count);
int totalDwords = checked(
cutoff * 0x105 + 0x53ea + bankDwords + stringDwords
+ GfxConstantDwords + state.GfxObjects.Count * GfxAllocationDwords);
byte[] payload = new byte[checked((totalDwords - 2) * 4)];
WriteInt(payload, 0, cutoff);
WriteInt(payload, 4, state.SavedFrameOwner);
WriteInt(payload, 8, state.BgmTrackId);
WriteIntList(payload, 0x0c, state.SoundEffectResourceIds);
state.ResourceRecords.CopyTo(payload, 0x34);
state.SurfaceRecords.CopyTo(payload, 0x4e4);
for (int i = 0; i < state.Frames.Count; i++)
WriteFrame(payload, FixedPrefixSize + i * FrameSize, state.Frames[i], i == cutoff);
int at = checked(0x5718 + cutoff * FrameSize);
int[] counts =
[
state.IntegerGlobals.Count, state.FloatGlobals.Count, state.StringGlobals.Count,
state.PointerGlobals.Count, state.PointerStrings.Count, state.LocalPointerScratch.Count,
];
WriteIntList(payload, at, counts);
at += 24;
WriteIntList(payload, at, state.IntegerGlobals);
at += state.IntegerGlobals.Count * 4;
WriteIntList(payload, at, state.FloatGlobals);
at += state.FloatGlobals.Count * 4;
WriteInt(payload, at, stringDwords);
at += 4;
strings.CopyTo(payload, at);
at += strings.Length;
WriteIntList(payload, at, state.PointerGlobals);
at += state.PointerGlobals.Count * 4;
WriteIntList(payload, at, state.PointerStrings);
at += state.PointerStrings.Count * 4;
WriteIntList(payload, at, state.LocalPointerScratch);
at += state.LocalPointerScratch.Count * 4;
WriteInt(payload, at, NativeNumberedSaveState.GfxRecordSize);
WriteInt(payload, at + 4, state.GfxObjects.Count);
at += 8;
foreach (NativeSavedGfxObject gfx in state.GfxObjects)
{
WriteInt(payload, at, unchecked((int)gfx.Handle));
gfx.Record.CopyTo(payload, at + 4);
at += 4 + NativeNumberedSaveState.GfxRecordSize;
}
WriteInt(payload, at, unchecked((int)state.RangeTransformFirst));
WriteInt(payload, at + 4, state.RangeTransformCount);
state.RangeTransformRecord.CopyTo(payload, at + 8);
return payload;
}
public static NativeNumberedSaveState Decode(ReadOnlySpan<byte> payload)
{
if (payload.Length < 0x5718)
throw new InvalidDataException("Numbered-save layout 3 payload is truncated.");
int cutoff = ReadNonNegative(payload, 0, "saved frame cutoff");
int fixedBytes = checked(0x5718 + cutoff * FrameSize);
Require(payload, 0, fixedBytes, "numbered-save fixed state");
int[] soundEffects = ReadInts(
payload, 0x0c, NativeNumberedSaveState.SoundEffectChannelCount);
byte[] resources = payload.Slice(0x34, NativeNumberedSaveState.ResourceRecordsSize).ToArray();
byte[] surfaces = payload.Slice(0x4e4, NativeNumberedSaveState.SurfaceRecordsSize).ToArray();
var frames = new NativeSavedScriptFrame[cutoff + 1];
for (int i = 0; i < frames.Length; i++)
frames[i] = ReadFrame(payload, FixedPrefixSize + i * FrameSize);
int at = fixedBytes;
int[] counts = ReadInts(payload, at, 6);
if (counts.Any(count => count < 0))
throw new InvalidDataException("Numbered-save layout 3 contains a negative bank count.");
at += 24;
int[] integers = ReadInts(payload, at, counts[0]);
at = checked(at + counts[0] * 4);
int[] floats = ReadInts(payload, at, counts[1]);
at = checked(at + counts[1] * 4);
int stringDwords = ReadNonNegative(payload, at, "string blob length");
at += 4;
int stringBytes = checked(stringDwords * 4);
Require(payload, at, stringBytes, "numbered-save string blob");
string[] strings = DecodeStrings(payload.Slice(at, stringBytes), counts[2]);
at += stringBytes;
int[] pointers = ReadInts(payload, at, counts[3]);
at = checked(at + counts[3] * 4);
int[] pointerStrings = ReadInts(payload, at, counts[4]);
at = checked(at + counts[4] * 4);
int[] localPointerScratch = ReadInts(payload, at, counts[5]);
at = checked(at + counts[5] * 4);
int gfxRecordSize = ReadNonNegative(payload, at, "gfx record size");
int gfxCount = ReadNonNegative(payload, at + 4, "gfx object count");
if (gfxRecordSize != NativeNumberedSaveState.GfxRecordSize)
throw new InvalidDataException($"Unsupported native gfx record size 0x{gfxRecordSize:x}.");
at += 8;
var objects = new NativeSavedGfxObject[gfxCount];
for (int i = 0; i < objects.Length; i++)
{
Require(payload, at, 4 + gfxRecordSize, "numbered-save gfx object");
long handle = ReadInt(payload, at);
objects[i] = new NativeSavedGfxObject(handle, payload.Slice(at + 4, gfxRecordSize).ToArray());
at += 4 + gfxRecordSize;
}
Require(payload, at, 8 + gfxRecordSize, "numbered-save range transform");
long rangeFirst = ReadInt(payload, at);
int rangeCount = ReadInt(payload, at + 4);
byte[] rangeRecord = payload.Slice(at + 8, gfxRecordSize).ToArray();
return new NativeNumberedSaveState(
ReadInt(payload, 4), ReadInt(payload, 8), soundEffects, resources, surfaces, frames,
integers, floats, strings, pointers, pointerStrings, localPointerScratch, objects,
rangeFirst, rangeCount, rangeRecord);
}
public static NativeNumberedSaveState Empty(IReadOnlyList<NativeSavedScriptFrame> frames)
=> new(
0, 0, new int[NativeNumberedSaveState.SoundEffectChannelCount],
new byte[NativeNumberedSaveState.ResourceRecordsSize],
new byte[NativeNumberedSaveState.SurfaceRecordsSize],
frames, Array.Empty<int>(), Array.Empty<int>(), Array.Empty<string>(),
Array.Empty<int>(), Array.Empty<int>(), Array.Empty<int>(),
Array.Empty<NativeSavedGfxObject>(), 0, 0,
new byte[NativeNumberedSaveState.GfxRecordSize]);
private static void WriteFrame(Span<byte> payload, int offset, NativeSavedScriptFrame frame, bool terminal)
{
if (frame.ReturnIndices.Count > FrameReturnCapacity)
throw new InvalidDataException("A native saved frame cannot hold more than 256 return entries.");
WriteInt(payload, offset, frame.ParentContext);
WriteInt(payload, offset + 4, unchecked((int)frame.ScriptId));
WriteInt(payload, offset + 8, frame.ReturnIndices.Count);
for (int i = 0; i < frame.ReturnIndices.Count; i++)
WriteInt(payload, offset + 12 + i * 4, frame.ReturnIndices[i]);
WriteInt(payload, offset + 0x40c, frame.ResumeIndex);
WriteInt(payload, offset + 0x410, terminal ? -1 : frame.CallTargetIndex);
}
private static NativeSavedScriptFrame ReadFrame(ReadOnlySpan<byte> payload, int offset)
{
int count = ReadNonNegative(payload, offset + 8, "frame return count");
if (count > FrameReturnCapacity)
throw new InvalidDataException("Numbered-save frame return count exceeds 256.");
return new NativeSavedScriptFrame(
ReadInt(payload, offset), unchecked((uint)ReadInt(payload, offset + 4)),
ReadInts(payload, offset + 12, count),
ReadInt(payload, offset + 0x40c), ReadInt(payload, offset + 0x410));
}
private static byte[] EncodeStrings(IReadOnlyList<string> strings)
{
using var stream = new MemoryStream();
foreach (string text in strings)
{
byte[] encoded = NativeEncoding.GetBytes(text ?? "");
stream.Write(encoded);
stream.WriteByte(0);
}
while ((stream.Length & 3) != 0) stream.WriteByte(0);
return stream.ToArray();
}
private static string[] DecodeStrings(ReadOnlySpan<byte> blob, int count)
{
var result = new string[count];
int at = 0;
for (int i = 0; i < count; i++)
{
if (at >= blob.Length)
throw new InvalidDataException("Numbered-save string blob ended before its declared string count.");
int end = blob[at..].IndexOf((byte)0);
if (end < 0)
throw new InvalidDataException("Numbered-save string blob ended before its declared string count.");
result[i] = NativeEncoding.GetString(blob.Slice(at, end));
at += end + 1;
}
return result;
}
private static void ValidateState(NativeNumberedSaveState state)
{
if (state.Frames.Count == 0) throw new InvalidDataException("A numbered save requires at least one frame.");
if (state.SoundEffectResourceIds.Count != NativeNumberedSaveState.SoundEffectChannelCount)
throw new InvalidDataException("Numbered-save sound-effect channel count must be 10.");
if (state.ResourceRecords.Length != NativeNumberedSaveState.ResourceRecordsSize)
throw new InvalidDataException("Numbered-save resource table must be 1,200 bytes.");
if (state.SurfaceRecords.Length != NativeNumberedSaveState.SurfaceRecordsSize)
throw new InvalidDataException("Numbered-save surface table must be 20,000 bytes.");
if (state.RangeTransformRecord.Length != NativeNumberedSaveState.GfxRecordSize
|| state.GfxObjects.Any(item => item.Record.Length != NativeNumberedSaveState.GfxRecordSize))
throw new InvalidDataException("Numbered-save gfx records must be 0x2d4 bytes.");
}
private static int[] ReadInts(ReadOnlySpan<byte> source, int offset, int count)
{
int bytes = checked(count * 4);
Require(source, offset, bytes, "numbered-save integer array");
var values = new int[count];
for (int i = 0; i < count; i++) values[i] = ReadInt(source, offset + i * 4);
return values;
}
private static void WriteIntList(Span<byte> destination, int offset, IReadOnlyList<int> values)
{
for (int i = 0; i < values.Count; i++) WriteInt(destination, offset + i * 4, values[i]);
}
private static int ReadNonNegative(ReadOnlySpan<byte> source, int offset, string name)
{
int value = ReadInt(source, offset);
if (value < 0) throw new InvalidDataException($"Numbered-save {name} is negative.");
return value;
}
private static int ReadInt(ReadOnlySpan<byte> source, int offset)
{
Require(source, offset, 4, "numbered-save dword");
return BinaryPrimitives.ReadInt32LittleEndian(source.Slice(offset, 4));
}
private static void WriteInt(Span<byte> destination, int offset, int value)
=> BinaryPrimitives.WriteInt32LittleEndian(destination.Slice(offset, 4), value);
private static void Require(ReadOnlySpan<byte> source, int offset, int count, string name)
{
if (offset < 0 || count < 0 || offset > source.Length - count)
throw new InvalidDataException($"{name} is truncated.");
}
private static Encoding CreateNativeEncoding()
{
Encoding.RegisterProvider(CodePagesEncodingProvider.Instance);
return Encoding.GetEncoding(932);
}
}