Use Array.Empty instead of zero-length allocation

src/Aardvark.Base.IO/Annotations.cs

@@ -45,7 +45,7 @@ internal readonly struct Annotated<T>
     {
         private readonly T m_value;
         private readonly IEnumerable<Annotation> m_tags;
-        private static readonly IEnumerable<Annotation> s_empty = new Annotation[0];
+        private static readonly IEnumerable<Annotation> s_empty = System.Array.Empty<Annotation>();
 
         public Annotated(T value)
         {

src/Aardvark.Base.IO/Converter.cs

@@ -49,8 +49,8 @@ public Convertible(string descriptor, object data)
         #region Properties
 
         public string Descriptor { get { return m_descriptor; } }
-        
-        public object Data 
+
+        public object Data
         {
             get { return m_data; }
             set { m_data = value; }
@@ -76,7 +76,7 @@ public static Convertible FromFile(string fileName)
         }
 
         /// <summary>
-        /// Creates a file convertible given a file name and a preferrable target used to 
+        /// Creates a file convertible given a file name and a preferrable target used to
         /// determine the shortest possible path (a matching creator must be registered).
         /// </summary>
         public static Convertible FromFile(string fileName, Convertible preferrableTarget)
@@ -103,8 +103,8 @@ public static Convertible FindMatchingRaw(Convertible c)
         }
 
         /// <summary>
-        /// Creates a matching raw convertible from a given convertible and a preferrable target 
-        /// used to the determine the shortest possible path (a matching raw convertible creator 
+        /// Creates a matching raw convertible from a given convertible and a preferrable target
+        /// used to the determine the shortest possible path (a matching raw convertible creator
         /// must be registered).
         /// </summary>
         public static Convertible FindMatchingRaw(Convertible c, Convertible preferrableTarget)
@@ -113,8 +113,8 @@ public static Convertible FindMatchingRaw(Convertible c, Convertible preferrable
         }
 
         /// <summary>
-        /// Creates a matching raw convertible from a given convertible and a preferrable target 
-        /// used to the determine the shortest possible path (a matching raw convertible creator 
+        /// Creates a matching raw convertible from a given convertible and a preferrable target
+        /// used to the determine the shortest possible path (a matching raw convertible creator
         /// must be registered).
         /// </summary>
         public static Convertible FindMatchingRaw(Convertible c, string preferrableTargetDescriptor)
@@ -169,7 +169,7 @@ public Convertible ConvertedTo(Convertible target)
         #endregion
 
         #region Query Methods
-    
+
         /// <summary>
         /// Returns whether a convertible is directly convertible into the target.
         /// </summary>
@@ -398,14 +398,14 @@ public void Convert(Convertible source, Convertible target)
         /// Private helper for public Convert method above.
         /// </summary>
         private void Convert(
-            Convertible source, Convertible target, 
+            Convertible source, Convertible target,
             Dictionary<string, Dictionary<string, RoutingEntry>> routingMap,
             List<Convertible> tempConvertibles)
         {
             var sourceDescr = source.Descriptor;
             var targetDescr = target.Descriptor;
 
-            if (sourceDescr == targetDescr) 
+            if (sourceDescr == targetDescr)
             {
                 DirectConvert(source, target);
                 return;
@@ -1029,7 +1029,7 @@ orderby distance ascending
 
         /// <summary>
         /// Sets whether a resource is available or not. By default, resources are
-        /// not available. If this is done after the routing table has been 
+        /// not available. If this is done after the routing table has been
         /// initialized once, the routing table will be rebuilt (therefore, use
         /// SetResourceAvailability(List{string} resources, bool available) if you need
         /// to set the availability of multiple resources).
@@ -1055,7 +1055,7 @@ public void SetResourceAvailability(string resource, bool available)
 
         /// <summary>
         /// Sets whether resources are available or not. By default, resources are
-        /// not available. If this is done after the routing table has been 
+        /// not available. If this is done after the routing table has been
         /// initialized once, the routing table will be rebuilt.
         /// </summary>
         public void SetResourceAvailability(List<string> resources, bool available)
@@ -1114,7 +1114,7 @@ private bool AreAllResourcesAvailable(string descriptor)
         {
             var reqResources = RequiredResources(descriptor);
 
-            if (reqResources == null) 
+            if (reqResources == null)
                 return true;
 
             foreach (var res in reqResources)
@@ -1168,7 +1168,7 @@ public Entry GetConversion(string sourceDescription, string targetDescription)
             }
             throw new ArgumentException();
         }
-        
+
         /// <summary>
         /// Enumerates all conversions in the specified conversion chain,
         /// or returns null if no conversion exists.
@@ -1192,7 +1192,7 @@ public IEnumerable<Annotation> GetAnnotations(string source, string target)
         {
             var key = (source, target);
             if (m_annotationsMap.ContainsKey(key)) return m_annotationsMap[key];
-            return new Annotation[0];
+            return Array.Empty<Annotation>();
         }
 
         /// <summary>

src/Aardvark.Base.IO/FieldCoderExtensions.cs

@@ -65,7 +65,7 @@ public static FieldCoder CreateFieldCoder(this Type type, string name, string me
             if (prop != null)
             {
                 // template:
-                // (c, o) => 
+                // (c, o) =>
                 // {
                 //     if (c.IsWriting) { var v = ((Foo)o).MyProperty; c.Code(ref v); }
                 //     else { var v = 0; c.Code(ref v); ((Foo)o).MyProperty = v; }
@@ -105,7 +105,7 @@ private static void EmitPropertyCoder(ILGenerator gen, Type type, PropertyInfo p
             var method_IsWriting = typeof(ICoder).GetMethod(
                 "get_IsWriting",
                 BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic,
-                null, new Type[] { }, null
+                null, Array.Empty<Type>(), null
                 );
 
             var method_Code = GetCodeMethodOverloadFor(prop.PropertyType);
@@ -141,12 +141,12 @@ private static void EmitPropertyCoder(ILGenerator gen, Type type, PropertyInfo p
             gen.Emit(OpCodes.Ldloca, 0);                        // load address of local variable v
             gen.Emit(OpCodes.Initobj, prop.PropertyType);       // initialize v to default value
 
-            // c.Code(ref v);                    
+            // c.Code(ref v);
             gen.Emit(OpCodes.Ldarg_0);                          // c, used as this for following call
             gen.Emit(OpCodes.Ldloca, 0);                        // ref v
             gen.Emit(OpCodes.Callvirt, method_Code);            // call ... c.code(ref v)
 
-            // ((T)o).MyProperty = v;  
+            // ((T)o).MyProperty = v;
             gen.Emit(OpCodes.Ldarg_1);                          // o
             gen.Emit(OpCodes.Castclass, type);                  // cast to T
             gen.Emit(OpCodes.Ldloc_0);                          // v

src/Aardvark.Base.IO/SymMap.cs

@@ -94,7 +94,7 @@ public IEnumerable<FieldCoder> GetFieldCoders(int coderVersion)
                     if (s_lastMapCodedVersionMap.TryGetValue(m_typeName, out lastMapCodedVersion)
                         && lastMapCodedVersion >= coderVersion)
                     {
-                        if (m_typeName == this.GetType().GetCanonicalName()) return new FieldCoder[0];
+                        if (m_typeName == this.GetType().GetCanonicalName()) return Array.Empty<FieldCoder>();
                         return new FieldCoder[]
                         {
                            new FieldCoder(0, "TypeName", (c, o) => c.CodePositiveSymbol(ref ((SymMap)o).m_typeName)),
@@ -119,7 +119,7 @@ public IEnumerable<FieldCoder> GetFieldCoders(int coderVersion)
                 }
             }
 
-            if (m_typeName == this.GetType().GetCanonicalName()) return new FieldCoder[0];
+            if (m_typeName == this.GetType().GetCanonicalName()) return Array.Empty<FieldCoder>();
 
             return new FieldCoder[]
             {

src/Aardvark.Base.IO/ZipFileContainer.cs

@@ -24,8 +24,8 @@ private struct SubFileHeader
             public long UncompressedSize;
         }
 
-        private string[] m_ZipFileNames = new string[0];
-        private WeakReference[] m_ZipFileStreams = new WeakReference[0];
+        private string[] m_ZipFileNames = Array.Empty<string>();
+        private WeakReference[] m_ZipFileStreams = Array.Empty<WeakReference>();
         private readonly SymbolDict<SubFileHeader> m_Files = new SymbolDict<SubFileHeader>();
         private readonly SymbolSet m_Directories = new SymbolSet();
         private readonly bool m_contentCaseSensitive = false;
@@ -97,7 +97,7 @@ public bool Init(string containerPath)
             Report.BeginTimed("Init Zip container '" + containerPath + "'.");
 
             FileStream mainFileStream = null;
-            FileStream[] zipStreams = new FileStream[0];
+            FileStream[] zipStreams = Array.Empty<FileStream>();
 
             try
             {
@@ -120,7 +120,7 @@ public bool Init(string containerPath)
 
                 zipStreams = new FileStream[zipEoCDR.cd_diskId + 1];
                 zipStreams[zipEoCDR.cd_diskId] = mainFileStream;
-                
+
                 // Load all parts of a multi zip
                 if (zipEoCDR.cd_diskId > 0)
                 {
@@ -142,7 +142,7 @@ public bool Init(string containerPath)
                         zipStreams[i] = File.Open(m_ZipFileNames[i], FileMode.Open, FileAccess.Read, FileShare.None);
                     }
                 }
-                
+
                 // Try to load Zip64 End Of Central Directory Locator
                 var zip64Locator = new TZip64EndOfCentralDirectoryLocator();
                 zip64Locator.Load(mainFileStream, zipEoCDR.Position);
@@ -399,6 +399,6 @@ private string SanitizeFilename(string fileName)
 
         #endregion
 
-        
+
     }
 }

src/Aardvark.Base/AlgoDat/INode.cs

@@ -1,4 +1,5 @@
 using Aardvark.Base;
+using System;
 using System.Collections.Generic;
 using System.Linq;
 
@@ -53,7 +54,7 @@ from n in sn.NodesAtDepth(depth - 1)
         /// </summary>
         public static IEnumerable<INode> DepthFirst(this INode self)
         {
-            if (self == null) return new INode[0];
+            if (self == null) return Array.Empty<INode>();
             return self.DepthFirst(n => n.SubNodes);
         }
 

src/Aardvark.Base/Extensions/IEnumerableExtensions.cs

@@ -19,7 +19,7 @@ public static IEnumerable<Guid> Guids()
             while (true) yield return Guid.NewGuid();
         }
     }
-    
+
     public static partial class EnumerableEx
     {
         #region Indexed Values
@@ -47,7 +47,7 @@ public static T[] SortedByDenseIndex<T>(
         }
 
         /// <summary>
-        /// Returns elements with index into 'other'. 
+        /// Returns elements with index into 'other'.
         /// </summary>
         public static IEnumerable<IndexedValue<T>> IndexIntoOther<T>(
                 this IEnumerable<T> self, IList<T> other)
@@ -58,7 +58,7 @@ public static IEnumerable<IndexedValue<T>> IndexIntoOther<T>(
         }
 
         #endregion
-        
+
         #region Special Selects
 
         public static IEnumerable<T> WhereNotNull<T>(this IEnumerable<T> self)
@@ -181,7 +181,7 @@ public static R[] SelectToArray<T, R>(this T[] self, Func<T, R> selector)
             }
             return result;
         }
-        
+
         /// <summary>
         /// Maps the elements of an array to a result list.
         /// </summary>
@@ -690,7 +690,7 @@ public static int PairsCount<T>(this IEnumerable<T> self, bool excludeIdenticalP
                     }
                 }
         }
-       
+
         /// <summary>
         /// [A B].Triples([x y], [X Y]) -> (A, x, X) (A, x, Y) (A, y, X) (A, y, Y) (B, x, X) (B, x, Y) (B, y, X) (B, y, Y) (C, x, X) (C, x, Y) (C, y, X) (C, y, Y)
         /// </summary>
@@ -759,7 +759,7 @@ public static IEnumerable<T> Dup<T>(this IEnumerable<T> self)
 
             foreach (var x in self) { yield return x; yield return x; }
         }
-        
+
         /// <summary>
         /// Duplicates each element of the sequence n times.
         /// [A B C].DupElements(4) -> [A A A A B B B B C C C C]
@@ -891,7 +891,7 @@ public static IEnumerable<T> NonNull<T>(IEnumerable<T> elements)
             if (elements == null) return Enumerable.Empty<T>();
             return elements;
         }
-        
+
         /// <summary>
         /// Compares both enumerables using SequenceEqual and additionally checks
         /// whether both enumerables are null.
@@ -964,7 +964,7 @@ public static T Max<T>(this IEnumerable<T> seq, Func<T, T, bool> greaterThan, T
 
         /// <summary>
         /// Aardvark.Runtime.IEnumerableExtensions:
-        /// Invokes a transform function on each element of a sequence and 
+        /// Invokes a transform function on each element of a sequence and
         /// returns the element that yielded the maximum value (and the maximum value in rv_maxVal).
         /// Only elements that yield larger values than minVal are considered.
         /// If multiple elements yield the maximum value, the first in the sequence is chosen.
@@ -1002,7 +1002,7 @@ public static TSrc MaxElement<TSrc, TDst>(this IEnumerable<TSrc> source, Func<TS
 
         /// <summary>
         /// Aardvark.Runtime.IEnumerableExtensions:
-        /// Invokes a transform function on each element of a sequence and 
+        /// Invokes a transform function on each element of a sequence and
         /// returns the element that yielded the minimum value (and the minimum value in rv_minVal).
         /// Only elements that yield smaller values than maxVal are considered.
         /// If multiple elements yield the minimum value, the first in the sequence is chosen.
@@ -2012,7 +2012,7 @@ public static bool TrueForAll<T>(
         }
 
         #endregion
-        
+
         #region Conversions
 
         public static T[] ToArrayDebug<T>(this IEnumerable<T> self)
@@ -2193,7 +2193,7 @@ public static TElement[] ToArray<TElement>(this IEnumerable<TElement> source, in
         {
             if (count == 0)
             {
-                return new TElement[0];
+                return Array.Empty<TElement>();
             }
             else
             {
@@ -2302,9 +2302,9 @@ public static int IndexOf<T>(this IEnumerable<T> list, T elementToFind)
             }
             return -1;
         }
-        
+
         /// <summary>
-        /// Concats single item to sequence. 
+        /// Concats single item to sequence.
         /// </summary>
         public static IEnumerable<T> Concat<T>(this IEnumerable<T> sequence, T item)
         {
@@ -2313,7 +2313,7 @@ public static IEnumerable<T> Concat<T>(this IEnumerable<T> sequence, T item)
         }
 
         /// <summary>
-        /// Concats sequence to single item. 
+        /// Concats sequence to single item.
         /// </summary>
         public static IEnumerable<T> Concat<T>(this T item, IEnumerable<T> sequence)
         {
@@ -2400,7 +2400,7 @@ public static IEnumerable<R> SelectMany<T, R>(this IEnumerable<T> self, Func<T,
         /// <summary>
         /// Converts a sequence that contains numbers of elements
         /// into a sequence that represents the indices of the
-        /// first element if the elements are stored in consecutive 
+        /// first element if the elements are stored in consecutive
         /// order and is closed by the total count elements.
         /// The length of the integrated sequence is +1 of the input.
         /// </summary>
@@ -2415,7 +2415,7 @@ public static IEnumerable<int> Integrated(this IEnumerable<int> counts, int sum
         }
 
         /// <summary>
-        /// Integrates a sequence of values. 
+        /// Integrates a sequence of values.
         /// Returns a sequence of N+1 values where the last is the sum off all value.
         /// </summary>
         public static IEnumerable<double> Integrated(this IEnumerable<double> values, double sum = 0)