Fix colection/LINQ usage in DiscSystem

except the garbage that is byte[].Skip().Take(), I CBB fixing that

src/BizHawk.Emulation.DiscSystem/CDFS/ISODirectoryNode.cs

@@ -122,12 +122,8 @@ namespace BizHawk.Emulation.DiscSystem
 				tabs += "  ";
 			}
 
-			// Get the names and sort
-			string[] names = this.Children.Keys.ToArray();
-			Array.Sort(names);
-
-			// Print the directory names recursively
-			foreach (string s in names)
+			// Print the directory names recursively, sorted alphabetically
+			foreach (string s in this.Children.Keys.OrderBy(s => s))
 			{
 				ISONode n = this.Children[s];
 				Console.WriteLine(tabs + s);

src/BizHawk.Emulation.DiscSystem/CDFS/ISOFile.cs

@@ -156,25 +156,16 @@ namespace BizHawk.Emulation.DiscSystem
 		public List<KeyValuePair<string, ISOFileNode>> EnumerateAllFilesRecursively()
 		{
 			fileNodes = new List<KeyValuePair<string, ISOFileNode>>();
+			if (Root.Children == null) return fileNodes;
+
 			dirsParsed = new List<ISODirectoryNode>();
-
-			if (Root.Children == null)
-				return fileNodes;
-
-			// get all folders
-			var dirs = (from a in Root.Children where a.Value.GetType() == typeof(ISODirectoryNode) select a);
-			// iterate through each folder
-			foreach (var d in dirs)
+			foreach (var idn in Root.Children.Values.OfType<ISODirectoryNode>()) // iterate through each folder
 			{
-				// process all files in this directory (and recursively process files in sub folders
-				ISODirectoryNode idn = (ISODirectoryNode) d.Value;
-				if (dirsParsed.Where(a => a == idn).Count() > 0)
-					continue;
-
+				// process all files in this directory (and recursively process files in subfolders)
+				if (dirsParsed.Contains(idn)) continue;
 				dirsParsed.Add(idn);
 				ProcessDirectoryFiles(idn.Children);                
 			}
-
 			return fileNodes.Distinct().ToList();
 		}  
 
@@ -184,7 +175,7 @@ namespace BizHawk.Emulation.DiscSystem
 			{
 				if (n.Value is ISODirectoryNode subdirNode)
 				{
-					if (dirsParsed.Where(a => a == subdirNode).Count() > 0) continue;
+					if (dirsParsed.Contains(subdirNode)) continue;
 					dirsParsed.Add(subdirNode);
 					ProcessDirectoryFiles(subdirNode.Children);
 				}

src/BizHawk.Emulation.DiscSystem/DiscFormats/Blobs/Blob_WaveFile.cs

@@ -94,7 +94,8 @@ namespace BizHawk.Emulation.DiscSystem
 						throw new Blob_WaveFile_Exception("Not a valid RIFF WAVE file (missing fmt chunk");
 					}
 
-					if (1 != rm.riff.subchunks.Count(chunk => chunk.tag == "data"))
+					var dataChunks = rm.riff.subchunks.Where(chunk => chunk.tag == "data").ToList();
+					if (dataChunks.Count != 1)
 					{
 						//later, we could make a Stream which would make an index of data chunks and walk around them
 						throw new Blob_WaveFile_Exception("Multi-data-chunk WAVE files not supported");
@@ -111,7 +112,7 @@ namespace BizHawk.Emulation.DiscSystem
 					}
 
 					//acquire the start of the data chunk
-					var dataChunk = (RiffMaster.RiffSubchunk) rm.riff.subchunks.First(chunk => chunk.tag == "data");
+					var dataChunk = (RiffMaster.RiffSubchunk) dataChunks[0];
 					waveDataStreamPos = dataChunk.Position;
 					mDataLength = dataChunk.Length;
 				}

src/BizHawk.Emulation.DiscSystem/DiscFormats/MDS_Format.cs

@@ -720,9 +720,8 @@ namespace BizHawk.Emulation.DiscSystem
 				{
 					int relMSF = -1;
 
-					var track = mdsf.TOCEntries.Where(t => t.Point == i).FirstOrDefault();
-					if (track == null)
-						break;
+					var track = mdsf.TOCEntries.FirstOrDefault(t => t.Point == i);
+					if (track == null) break;
 
 					// ignore the info entries
 					if (track.Point == 0xA0 ||
@@ -733,10 +732,12 @@ namespace BizHawk.Emulation.DiscSystem
 					}
 
 					// get the blob(s) for this track
-					// its probably a safe assumption that there will be only one blob per track, 
-					// but i'm still not 100% sure on this 
+					// it's probably a safe assumption that there will be only one blob per track, but I'm still not 100% sure on this
 					var tr = mdsf.TOCEntries.FirstOrDefault(a => a.Point == i) ?? throw new MDSParseException("BLOB Error!");
 
+#if true
+					if (tr.ImageFileNamePaths.Count == 0) throw new MDSParseException("BLOB Error!");
+#else // this is the worst use of lists and LINQ I've seen in this god-forsaken codebase, I hope for all our sakes that it's not a workaround for some race condition --yoshi
 					List<string> blobstrings = new List<string>();
 					foreach (var t in tr.ImageFileNamePaths)
 					{
@@ -752,6 +753,7 @@ namespace BizHawk.Emulation.DiscSystem
 
 					// is the currBlob valid for this track, or do we need to increment?   
 					string bString = tBlobs.First();
+#endif
 
 					IBlob mdfBlob = null;
 					

src/BizHawk.Emulation.DiscSystem/DiscIdentifier.cs

@@ -203,20 +203,15 @@ namespace BizHawk.Emulation.DiscSystem
 				if (sysId == "ASAHI-CDV")
 					return DiscType.Playdia;
 
-				if (sysId == "CDTV" || sysId == "AMIGA")
+				if (sysId == "CDTV" || sysId == "AMIGA"
+					|| iso.Root.Children.Keys.Any(k => k.ToLowerInvariant().Contains("cd32")))
+				{
 					return DiscType.Amiga;
-				foreach (var f in iso.Root.Children)
-					if (f.Key.ToLower().Contains("cd32"))
-						return DiscType.Amiga;
+				}
 
 				// NeoGeoCD Check
-				var absTxt = iso.Root.Children.Where(a => a.Key.Contains("ABS.TXT")).ToList();
-				if (absTxt.Count > 0)
-				{
-					if (SectorContains("abstracted by snk", Convert.ToInt32(absTxt.First().Value.Offset)))
-						return DiscType.NeoGeoCD;
-				}
-					
+				var absTxt = iso.Root.Children.Where(kvp => kvp.Key.Contains("ABS.TXT")).Select(kvp => kvp.Value).FirstOrDefault();
+				if (absTxt != null && SectorContains("abstracted by snk", Convert.ToInt32(absTxt.Offset))) return DiscType.NeoGeoCD;
 
 				return DiscType.UnknownCDFS;
 			}