Texture loading: reduce memory allocations (#6623)

* rebase

* add methods Ryyjinx.Common EmbeddedResources and SteamUtils

* GAL changes - change SetData() methods and ThreadedTexture commands to use IMemoryOwner<byte> instead of SpanOrArray<byte>

* Ryujinx.Graphics.Texture: change texture conversion methods to return IMemoryOwner<byte> and allocate from ByteMemoryPool

* Ryujinx.Graphics.OpenGL: update ITexture and Texture-like types with SetData() methods to take IMemoryOwner<byte> instead of SpanOrArray<byte>

* Ryujinx.Graphics.Vulkan: update ITexture and Texture-like types with SetData() methods to take IMemoryOwner<byte> instead of SpanOrArray<byte>

* Ryujinx.Graphics.Gpu: update ITexture and Texture-like types with SetData() methods to take IMemoryOwner<byte> instead of SpanOrArray<byte>

* Remove now-unused SpanOrArray<T>

* post-rebase cleanup

* PixelConverter: remove unsafe modifier on safe methods, and remove one unnecessary cast

* use ByteMemoryPool.Rent() in GetWritableRegion() impls

* fix formatting, rename `ReadRentedMemory()` to `ReadFileToRentedMemory()``

* Texture.ConvertToHostCompatibleFormat(): dispose of `result` in Astc decode branch

src/Ryujinx.Common/Utilities/StreamUtils.cs

@@ -1,4 +1,6 @@
+using Microsoft.IO;
 using Ryujinx.Common.Memory;
+using System.Buffers;
 using System.IO;
 using System.Threading;
 using System.Threading.Tasks;
@@ -9,12 +11,50 @@ namespace Ryujinx.Common.Utilities
     {
         public static byte[] StreamToBytes(Stream input)
         {
-            using MemoryStream stream = MemoryStreamManager.Shared.GetStream();
+            using RecyclableMemoryStream output = StreamToRecyclableMemoryStream(input);
 
+            return output.ToArray();
+        }
 
-            input.CopyTo(stream);
+        public static IMemoryOwner<byte> StreamToRentedMemory(Stream input)
+        {
+            if (input is MemoryStream inputMemoryStream)
+            {
+                return MemoryStreamToRentedMemory(inputMemoryStream);
+            }
+            else if (input.CanSeek)
+            {
+                long bytesExpected = input.Length;
 
-            return stream.ToArray();
+                IMemoryOwner<byte> ownedMemory = ByteMemoryPool.Rent(bytesExpected);
+
+                var destSpan = ownedMemory.Memory.Span;
+
+                int totalBytesRead = 0;
+
+                while (totalBytesRead < bytesExpected)
+                {
+                    int bytesRead = input.Read(destSpan[totalBytesRead..]);
+
+                    if (bytesRead == 0)
+                    {
+                        ownedMemory.Dispose();
+
+                        throw new IOException($"Tried reading {bytesExpected} but the stream closed after reading {totalBytesRead}.");
+                    }
+
+                    totalBytesRead += bytesRead;
+                }
+
+                return ownedMemory;
+            }
+            else
+            {
+                // If input is (non-seekable) then copy twice: first into a RecyclableMemoryStream, then to a rented IMemoryOwner<byte>.
+                using RecyclableMemoryStream output = StreamToRecyclableMemoryStream(input);
+
+                return MemoryStreamToRentedMemory(output);
+            }
         }
 
         public static async Task<byte[]> StreamToBytesAsync(Stream input, CancellationToken cancellationToken = default)
@@ -25,5 +65,26 @@ namespace Ryujinx.Common.Utilities
 
             return stream.ToArray();
         }
+
+        private static IMemoryOwner<byte> MemoryStreamToRentedMemory(MemoryStream input)
+        {
+            input.Position = 0;
+
+            IMemoryOwner<byte> ownedMemory = ByteMemoryPool.Rent(input.Length);
+
+            // Discard the return value because we assume reading a MemoryStream always succeeds completely.
+            _ = input.Read(ownedMemory.Memory.Span);
+
+            return ownedMemory;
+        }
+
+        private static RecyclableMemoryStream StreamToRecyclableMemoryStream(Stream input)
+        {
+            RecyclableMemoryStream stream = MemoryStreamManager.Shared.GetStream();
+
+            input.CopyTo(stream);
+
+            return stream;
+        }
     }
 }