More documentation I don't want to lose and some code cleanup as I understand LZH better...er?

2024-09-22 16:22:04 -06:00
parent 3425a28bf7
commit d39e73a6fa
16 changed files with 5852 additions and 0 deletions
@@ -0,0 +1,58 @@
+using System.Buffers.Binary;
+
+namespace fxl.codes.kisekae.data.Archives;
+
+internal static class EndianUtility
+{
+    public static int ToLittleEndian(this ReadOnlySpan<byte> bytes)
+    {
+        var x = BitConverter.ToInt32(bytes);
+        return BitConverter.IsLittleEndian ? x : BinaryPrimitives.ReverseEndianness(x);
+    }
+
+    public static int ReadLittleEndian(this Stream stream, int length = 4)
+    {
+        var buffer = new byte[length];
+        stream.ReadExactly(buffer);
+        return ToLittleEndian(buffer);
+    }
+
+    public static async Task<int> ReadLittleEndianAsync(this Stream stream, int length = 4)
+    {
+        var buffer = new byte[length];
+        await stream.ReadExactlyAsync(buffer);
+        return ToLittleEndian(buffer);
+    }
+
+    public static DateTime ToDateTime(this ReadOnlySpan<byte> bytes)
+    {
+        var time = ToLittleEndian(bytes);
+        return ToDateTime(time);
+    }
+
+    private static DateTime ToDateTime(int time)
+    {
+        var year = ((time >> 25) & 0x7f) + 1980;
+        var month = (time >> 21) & 0x0f;
+        var day = (time >> 16) & 0x1f;
+        var hour = (time >> 11) & 0x1f;
+        var minute = (time >> 5) & 0x3f;
+        var second = (time & 0x1f) * 2;
+
+        if (month is < 1 or > 12 || day is < 1 or > 31 || hour >= 24 || minute >= 60 || second > 60) return DateTime.MinValue;
+
+        return new DateTime(year, month, day, hour, minute, second);
+    }
+
+    public static DateTime ReadLittleEndianDateTime(this Stream stream)
+    {
+        var time = ReadLittleEndian(stream);
+        return ToDateTime(time);
+    }
+
+    public static async Task<DateTime> ReadLittleEndianDateTimeAsync(this Stream stream)
+    {
+        var time = await ReadLittleEndianAsync(stream);
+        return ToDateTime(time);
+    }
+}