From 8c4603c73675958efc960fbd4bb599a2909d106a Mon Sep 17 00:00:00 2001
From: Konstantin <const@const.me>
Date: Mon, 16 Jan 2023 14:52:43 +0100
Subject: Source codes

---
 Tools/CompressShaders/DetectFp64.cs | 43 +++++++++++++++++++++++++++++++++++++
 1 file changed, 43 insertions(+)
 create mode 100644 Tools/CompressShaders/DetectFp64.cs

(limited to 'Tools/CompressShaders/DetectFp64.cs')

diff --git a/Tools/CompressShaders/DetectFp64.cs b/Tools/CompressShaders/DetectFp64.cs
new file mode 100644
index 0000000..1d75126
--- /dev/null
+++ b/Tools/CompressShaders/DetectFp64.cs
@@ -0,0 +1,43 @@
+#pragma warning disable CS0649
+using System.Runtime.InteropServices;
+
+namespace CompressShaders
+{
+	static class DetectFp64
+	{
+		struct DXBCHeader
+		{
+			public uint FourCC; // Four character code "DXBC"
+			public uint Hash0;            // 32-bit hash of the DXBC file
+			public uint Hash1;            // 32-bit hash of the DXBC file
+			public uint Hash2;            // 32-bit hash of the DXBC file
+			public uint Hash3;            // 32-bit hash of the DXBC file
+			public uint unknownOne;
+			public uint TotalSize;        // Total size of the DXBC file in bytes
+			public int NumChunks;        // Number of chunks in the DXBC file
+		};
+
+		public static bool usesFp64( ReadOnlySpan<byte> dxbc )
+		{
+			ReadOnlySpan<DXBCHeader> dxbcHeaderSpan = MemoryMarshal.Cast<byte, DXBCHeader>( dxbc );
+			DXBCHeader dxbcHeader = dxbcHeaderSpan[ 0 ];
+
+			int cbHeader = Marshal.SizeOf<DXBCHeader>();
+			int nChunks = dxbcHeader.NumChunks;
+			ReadOnlySpan<int> chunkOffsets = MemoryMarshal.Cast<byte, int>( dxbc.Slice( cbHeader, nChunks * 4 ) );
+			foreach( int off in chunkOffsets )
+			{
+				uint id = MemoryMarshal.Cast<byte, uint>( dxbc.Slice( off, 4 ) )[ 0 ];
+				const uint SFI0 = 0x30494653;
+				if( id != SFI0 )
+					continue;
+				int size = MemoryMarshal.Cast<byte, int>( dxbc.Slice( off + 4, 4 ) )[ 0 ];
+				if( size < 4 )
+					throw new ApplicationException();
+				uint data = MemoryMarshal.Cast<byte, uint>( dxbc.Slice( off + 8, 4 ) )[ 0 ];
+				return 0 != ( data & 1u );
+			}
+			return false;
+		}
+	}
+}
\ No newline at end of file
-- 
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