pkNX/pkNX.Containers/SARC/SFAT.cs

using System;
using System.Collections.Generic;
using System.IO;

namespace pkNX.Containers
{
    /// <summary>
    /// <see cref="SARC"/> File Access Table
    /// </summary>
    public class SFAT
    {
        public const string Identifier = nameof(SFAT);

        /// <summary>
        /// The required <see cref="Magic"/> matches the first 4 bytes of the file data.
        /// </summary>
        public bool SigMatches => Magic == Identifier;

        private readonly string Magic = Identifier;
        private readonly ushort HeaderSize = 0xC;
        private readonly ushort EntryCount;
        private readonly uint HashMult = 0x65;
        public readonly List<SFATEntry> Entries;

        public SFATEntry this[int index]
        {
            get => Entries[index];
            set => Entries[index] = value;
        }

        public SFAT(string baseFolder, IReadOnlyList<string> files)
        {
            EntryCount = (ushort)files.Count;
            Entries = new List<SFATEntry>(EntryCount);
            for (int i = 0; i < EntryCount; i++)
            {
                Entries[i] = new SFATEntry {File = files[i]};

                var fn = files[i].Remove(baseFolder.Length);
                Entries[i].SetFileName(fn, HashMult);
            }
        }

        public SFAT(BinaryReader br, int DataOffset)
        {
            Magic = new string(br.ReadChars(4));
            if (!SigMatches)
                throw new FormatException(nameof(SFAT));

            HeaderSize = br.ReadUInt16();
            EntryCount = br.ReadUInt16();
            HashMult = br.ReadUInt32();
            Entries = new List<SFATEntry>(EntryCount);

            for (int i = 0; i < EntryCount; i++)
                Entries.Add(new SFATEntry(br, DataOffset));
        }

        public string GetFileName(int index, Stream parent, int StringOffset) => this[index].GetFileName(parent, StringOffset);
        public void SetFileName(int index, string value) => this[index].SetFileName(value, HashMult);

        public void Write(BinaryWriter bw)
        {
            foreach (var c in Magic)
                bw.Write((byte)c);
            bw.Write(HeaderSize);
            bw.Write(EntryCount);
            bw.Write(HashMult);
            WriteEntries(bw);
        }

        public void WriteEntries(BinaryWriter bw)
        {
            foreach (var entry in Entries)
                entry.Write(bw);
        }
    }
}