Faster non-positional algorithm for positional partial sub-keys.

protobufel · Jun 4, 2017 · 1c0b976 · 1c0b976
1 parent 1b4ecc7
commit 1c0b976
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Showing 2 changed files with 38 additions and 22 deletions.
diff --git a/MultiKeyMap/Base/NonPositionalBaseMultiKeyMap.cs b/MultiKeyMap/Base/NonPositionalBaseMultiKeyMap.cs
@@ -149,7 +149,7 @@ public override bool TryGetFullKeysByPartialKey(IEnumerable<T> subKeys, IEnumera
                 return false;
             }
 
-            ISet<K> result;
+            HashSet<K> result;
 
             if (GetAtOrNegative(positionList, minPos) < 0)
             {
@@ -172,53 +172,69 @@ public override bool TryGetFullKeysByPartialKey(IEnumerable<T> subKeys, IEnumera
             {
                 if (i != minPos)
                 {
-                    if (!TryGetFilteredFullKeys(GetAtOrNegative(positionList, i), subKeyList[i], subResults[i], out ISet<K> filteredSubResult))
+                    result.IntersectWith(subResults[i]);
+
+                    if (result.Count == 0)
                     {
-                        fullKeys = default(IEnumerable<K>);
+                        fullKeys = default(ISet<K>);
                         return false;
                     }
+                }
+            }
 
-                    result.IntersectWith(filteredSubResult);
+            var subKeyPosList = subKeyList
+                .Zip<T, int, (T subKey, int position)>(positionList, (subKey, position) => (subKey, position))
+                .Where((tuple, index) => (index != minPos) && (tuple.position > 0))
+                .ToList();
 
-                    if (result.Count == 0)
+            if (subKeyPosList.Count != 0)
+            {
+                // could be streamed via IEnumerable result.Where(<the predicate opposite the one below>) but then subKeyList and positionList should always be copied
+                result.RemoveWhere(key =>
+                {
+                    foreach (var subKeyPos in subKeyPosList)
                     {
-                        fullKeys = default(IEnumerable<K>);
-                        return false;
+                        if (!SubKeyComparer.Equals(subKeyPos.subKey, key.ElementAtOrDefault(subKeyPos.position)))
+                        {
+                            return true;
+                        }
                     }
+
+                    return false;
+                });
+
+                if (result.Count == 0)
+                {
+                    fullKeys = default(IEnumerable<K>);
+                    return false;
                 }
             }
 
             fullKeys = result;
             return true;
         }
 
-        protected virtual bool TryGetFilteredFullKeys(int position, T subkey, ISet<K> source, out ISet<K> target)
+        protected virtual bool TryGetFilteredFullKeys(int position, T subKey, ISet<K> source, out HashSet<K> target)
         {
             if (source.Count == 0)
             {
-                target = default(ISet<K>);
+                target = default(HashSet<K>);
                 return false;
             }
 
-            if (position < 0)
-            {
-                target = source;
-                return true;
-            }
-
             target = new HashSet<K>(EqualityComparerExtensions.ReferenceEqualityComparerOf<K>());
 
             foreach (K fullKey in source)
             {
-                if (SubKeyComparer.Equals(subkey, fullKey.ElementAtOrDefault(position)))
+                if (SubKeyComparer.Equals(subKey, fullKey.ElementAtOrDefault(position)))
                 {
                     target.Add(fullKey);
                 }
             }
 
             if (target.Count == 0)
             {
-                target = default(ISet<K>);
+                target = default(HashSet<K>);
                 return false;
             }
 
@@ -248,7 +264,7 @@ protected override void DeletePartial(K key)
 
         protected override void ClearPartial()
         {
-                partMap.Clear();
+            partMap.Clear();
         }
 
         #endregion

diff --git a/MultiKeyMap/MultiKeyMap.csproj b/MultiKeyMap/MultiKeyMap.csproj
@@ -13,13 +13,13 @@
     <RepositoryUrl>https://github.com/protobufel/multikeymapcsharp</RepositoryUrl>
     <RepositoryType>git</RepositoryType>
     <PackageTags>c# library multikey dictionary</PackageTags>
-    <PackageReleaseNotes>Added license to all files; same Apache 2.0 license!</PackageReleaseNotes>
+    <PackageReleaseNotes>Faster non-positional algorithm when dealing with positional partial sub-keys.</PackageReleaseNotes>
     <PackageRequireLicenseAcceptance>True</PackageRequireLicenseAcceptance>
     <GeneratePackageOnBuild>True</GeneratePackageOnBuild>
     <SignAssembly>False</SignAssembly>
-    <AssemblyVersion>4.2.21.0</AssemblyVersion>
-    <FileVersion>4.2.21.0</FileVersion>
-    <Version>4.2.21</Version>
+    <AssemblyVersion>4.3.0.0</AssemblyVersion>
+    <FileVersion>4.3.0.0</FileVersion>
+    <Version>4.3.0</Version>
   </PropertyGroup>
 
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|AnyCPU'">