Files
OpenMaidEngine/engine/Age.Engine/Sys4/Sys4AssetCatalog.cs
2026-07-21 20:23:32 -04:00

231 lines
11 KiB
C#

using System.Buffers.Binary;
using System.Text;
namespace Age.Engine.Sys4;
/// <summary>One raw SYS4INI file record. Placeholder records remain addressable by
/// <see cref="RawIndex"/> but are excluded from scene and name views.</summary>
public sealed record AssetEntry(
string Name,
string Archive,
long Offset,
long Size,
int RawIndex = -1,
int ArchiveId = -1,
int FileNumber = -1,
bool IsPlaceholder = false,
int PackId = 0)
{
/// <summary>The exact packed SYS4INI/AAI id AGE uses to address this record.</summary>
public int PackedId => checked((PackId << 24) | RawIndex);
}
/// <summary>A real catalog entry paired with the packed resource id AGE uses at runtime.</summary>
public sealed record PackedAssetEntry(long PackedId, AssetEntry Asset);
/// <summary>Runtime parser and lookup views for a base S4IC SYS4INI catalog and its S4AC append mounts.</summary>
public sealed class Sys4AssetCatalog
{
private const int ArchiveNameSize = 256;
private const int RecordSize = 80;
private readonly Dictionary<string, AssetEntry> _byName;
private readonly Dictionary<string, (int Start, int End)> _sceneRanges;
private readonly Dictionary<int, Sys4AssetCatalog> _appendPacks = new();
public string Magic { get; }
public string Title { get; }
public int PackId { get; }
public IReadOnlyList<string> Archives { get; }
public IReadOnlyList<AssetEntry> RawSlots { get; }
public IReadOnlyList<AssetEntry> Files { get; }
public IReadOnlyDictionary<int, Sys4AssetCatalog> AppendPacks => _appendPacks;
private Sys4AssetCatalog(string magic, string title, int packId,
List<string> archives, List<AssetEntry> rawSlots)
{
Magic = magic;
Title = title;
PackId = packId;
Archives = archives;
RawSlots = rawSlots;
Files = rawSlots.Where(r => !r.IsPlaceholder).ToArray();
_byName = Files.ToDictionary(r => r.Name, StringComparer.OrdinalIgnoreCase);
_sceneRanges = BuildSceneRanges(Files);
}
public static Sys4AssetCatalog Load(string path)
{
var catalog = Parse(File.ReadAllBytes(path), Path.GetFileName(path));
if (!catalog.Magic.StartsWith("S4IC", StringComparison.Ordinal)) return catalog;
string? root = Path.GetDirectoryName(Path.GetFullPath(path));
if (root == null) return catalog;
foreach (string appendPath in Directory.EnumerateFiles(root, "*.AAI"))
catalog.MountAppend(Parse(File.ReadAllBytes(appendPath), Path.GetFileName(appendPath)));
return catalog;
}
public static Sys4AssetCatalog Parse(byte[] data, string name = "SYS4INI.BIN")
{
bool isBase = data.Length >= 4 && data.AsSpan(0, 4).SequenceEqual("S4IC"u8);
bool isAppend = data.Length >= 4 && data.AsSpan(0, 4).SequenceEqual("S4AC"u8);
if (!isBase && !isAppend)
throw new InvalidDataException($"{name}: expected an S4IC or S4AC catalog");
int expandedSizeOffset = isAppend ? 0x110 : 0x12c;
int packedSizeOffset = isAppend ? 0x114 : 0x134;
if (data.Length < packedSizeOffset + 4)
throw new InvalidDataException($"{name}: catalog header is truncated");
uint expandedSize = BinaryPrimitives.ReadUInt32LittleEndian(data.AsSpan(expandedSizeOffset, 4));
uint packedSize = BinaryPrimitives.ReadUInt32LittleEndian(data.AsSpan(packedSizeOffset, 4));
if (packedSize > data.Length - (packedSizeOffset + 4))
throw new InvalidDataException($"{name}: packed directory is truncated");
if (expandedSize == 0 || expandedSize > int.MaxValue)
throw new InvalidDataException($"{name}: invalid expanded size {expandedSize}");
var blob = LzssDecoder.Decode(data.AsSpan(packedSizeOffset + 4, checked((int)packedSize)),
checked((int)expandedSize), name);
int p = 0;
uint ReadU32()
{
if (p > blob.Length - 4) throw new InvalidDataException($"{name}: directory is truncated");
uint value = BinaryPrimitives.ReadUInt32LittleEndian(blob.AsSpan(p, 4));
p += 4;
return value;
}
uint archiveCount = ReadU32();
if (archiveCount is 0 or >= 0x1000 || archiveCount > (blob.Length - p) / ArchiveNameSize)
throw new InvalidDataException($"{name}: invalid archive count {archiveCount}");
var archives = new List<string>(checked((int)archiveCount));
for (int i = 0; i < archiveCount; i++, p += ArchiveNameSize)
archives.Add(ReadCString(blob.AsSpan(p, ArchiveNameSize)));
uint fileCount = ReadU32();
if (fileCount is 0 or >= 0x400000 || fileCount > (blob.Length - p) / RecordSize)
throw new InvalidDataException($"{name}: invalid file count {fileCount}");
int packId = isAppend
? checked((int)BinaryPrimitives.ReadUInt32LittleEndian(data.AsSpan(0x108, 4))) : 0;
// AGE uses SAR 24 before indexing its mount table, so selectors with the sign bit set do
// not address slots 0x80..0xff. Reject them instead of inventing unsigned behavior.
if (isAppend && packId is not (> 0 and < 0x80))
throw new InvalidDataException($"{name}: invalid append pack selector {packId}");
var slots = new List<AssetEntry>(checked((int)fileCount));
for (int i = 0; i < fileCount; i++, p += RecordSize)
{
var row = blob.AsSpan(p, RecordSize);
string fileName = ReadCString(row[..64]);
int archiveId = checked((int)BinaryPrimitives.ReadUInt32LittleEndian(row.Slice(64, 4)));
int fileNumber = checked((int)BinaryPrimitives.ReadUInt32LittleEndian(row.Slice(68, 4)));
long offset = BinaryPrimitives.ReadUInt32LittleEndian(row.Slice(72, 4));
long size = BinaryPrimitives.ReadUInt32LittleEndian(row.Slice(76, 4));
string archive = archiveId >= 0 && archiveId < archives.Count ? archives[archiveId] : "";
bool placeholder = fileName is "" or "@";
slots.Add(new AssetEntry(fileName, archive, offset, size, i, archiveId, fileNumber,
placeholder, packId));
}
string magic = ReadCString(data.AsSpan(0, Math.Min(8, data.Length)));
string title = ReadCString(data.AsSpan(8, Math.Min(256, data.Length - 8)));
return new Sys4AssetCatalog(magic, title, packId, archives, slots);
}
/// <summary>Mount an append catalog by its native header selector. A later mount of the same
/// selector replaces the earlier one, matching AGE's FindNextFile/store loop.</summary>
public void MountAppend(Sys4AssetCatalog append)
{
if (PackId != 0) throw new InvalidOperationException("append catalogs cannot own append mounts");
if (!append.Magic.StartsWith("S4AC", StringComparison.Ordinal) || append.PackId == 0)
throw new InvalidDataException("mounted catalog is not an S4AC append pack");
if (!string.Equals(Title, append.Title, StringComparison.Ordinal))
throw new InvalidDataException($"append title mismatch: {append.Title}");
_appendPacks[append.PackId] = append;
}
/// <summary>Universal raw-id lookup. Placeholder slots are returned, not collapsed.</summary>
public AssetEntry? ResolveRaw(long rawId)
=> rawId >= 0 && rawId < RawSlots.Count ? RawSlots[(int)rawId] : null;
/// <summary>Native packed-id lookup: zero high byte selects SYS4INI; otherwise the high byte
/// selects an S4AC mount and the low 24 bits index that pack.</summary>
public AssetEntry? ResolvePacked(long id)
{
if (id < 0 || id > uint.MaxValue) return null;
int pack = (int)((id >> 24) & 0xff);
if (pack >= 0x80) return null;
long index = id & 0xffffff;
return pack == 0 ? ResolveRaw(index)
: _appendPacks.TryGetValue(pack, out var append) ? append.ResolveRaw(index) : null;
}
/// <summary>Case-insensitive exact-name lookup over real records.</summary>
public AssetEntry? ResolveName(string name)
=> _byName.TryGetValue(Path.GetFileName(name), out var entry) && Path.GetFileName(name) == name
? entry : null;
/// <summary>Resolve within the owning scene section; ids cannot spill into the next section.</summary>
public AssetEntry? ResolveScene(string scene, long localId)
{
string key = Path.GetFileNameWithoutExtension(scene);
if (!_sceneRanges.TryGetValue(key, out var range)) return null;
long pos = range.Start + localId;
return localId >= 0 && pos <= range.End ? Files[(int)pos] : null;
}
public IReadOnlyList<string> ScriptNames => Files
.Where(f => f.Name.EndsWith(".BIN", StringComparison.OrdinalIgnoreCase))
.Select(f => f.Name.ToUpperInvariant()).ToArray();
/// <summary>Enumerate every script in native packed-id order, including mounted append packs.
/// Placeholder slots and non-script assets are excluded without collapsing raw indices.</summary>
public IReadOnlyList<PackedAssetEntry> EnumerateScripts()
{
var scripts = new List<PackedAssetEntry>();
AddScripts(this, scripts);
foreach (var append in _appendPacks.OrderBy(pair => pair.Key).Select(pair => pair.Value))
AddScripts(append, scripts);
return scripts;
}
private static void AddScripts(Sys4AssetCatalog catalog, List<PackedAssetEntry> scripts)
{
long selector = (long)catalog.PackId << 24;
foreach (var entry in catalog.Files)
if (entry.Name.EndsWith(".BIN", StringComparison.OrdinalIgnoreCase))
scripts.Add(new PackedAssetEntry(selector | (uint)entry.RawIndex, entry));
}
private static Dictionary<string, (int Start, int End)> BuildSceneRanges(IReadOnlyList<AssetEntry> files)
{
var ranges = new Dictionary<string, (int Start, int End)>(StringComparer.OrdinalIgnoreCase);
int start = 0;
for (int i = 1; i <= files.Count; i++)
{
bool end = i == files.Count || files[i].FileNumber <= files[i - 1].FileNumber;
if (!end) continue;
for (int k = start; k < i; k++)
if (files[k].Name.Length == 10 && files[k].Name.StartsWith("SC", StringComparison.OrdinalIgnoreCase)
&& files[k].Name.EndsWith(".BIN", StringComparison.OrdinalIgnoreCase)
&& files[k].Name.AsSpan(2, 4).ToString().All(char.IsDigit))
{
ranges[Path.GetFileNameWithoutExtension(files[k].Name)] = (start, i - 1);
break;
}
start = i;
}
return ranges;
}
private static string ReadCString(ReadOnlySpan<byte> bytes)
{
int zero = bytes.IndexOf((byte)0);
if (zero >= 0) bytes = bytes[..zero];
Encoding.RegisterProvider(CodePagesEncodingProvider.Instance);
return Encoding.GetEncoding(932).GetString(bytes);
}
}