Keywords

Src/Data/Myc.Data.Keyword.pas

@@ -11,7 +11,9 @@ uses
 type
     // The runtime representation of an interned keyword
     IKeyword = interface(IInterface)
+        function GetIdx: Integer;
         function GetName: string;
+        property Idx: Integer read GetIdx;
         property Name: string read GetName;
     end;
 
@@ -22,9 +24,11 @@ type
             TKeyword = class(TInterfacedObject, IKeyword)
             private
                 FName: string;
+                FIdx: Integer;
                 function GetName: string;
+                function GetIdx: Integer;
             public
-                constructor Create(const AName: string);
+                constructor Create(const AName: string; AIdx: Integer);
             end;
     strict private
         class var
@@ -38,14 +42,38 @@ type
         class function Intern(const AName: string): IKeyword; static;
     end;
 
+    TKeywordMapping<T> = record
+        type
+            TField = record
+                Key: IKeyword;
+                Value: T;
+            public
+                constructor Create(const AKey: IKeyword; const AValue: T);
+            end;
+    private
+        FMap: TArray<Integer>;
+        FFields: TArray<TField>;
+        FFirst, FLast: Integer;
+    public
+        constructor Create(const AFields: TArray<TField>);
+        function IndexOf(const Key: IKeyword): Integer;
+        property Fields: TArray<TField> read FFields;
+    end;
+
 implementation
 
 { TKeywordRegistry.TKeyword }
 
-constructor TKeywordRegistry.TKeyword.Create(const AName: string);
+constructor TKeywordRegistry.TKeyword.Create(const AName: string; AIdx: Integer);
 begin
     inherited Create;
     FName := AName;
+    FIdx := AIdx;
+end;
+
+function TKeywordRegistry.TKeyword.GetIdx: Integer;
+begin
+    Result := FIdx;
 end;
 
 function TKeywordRegistry.TKeyword.GetName: string;
@@ -72,7 +100,7 @@ begin
     try
         if not FRegistry.TryGetValue(AName, Result) then
         begin
-            Result := TKeyword.Create(AName);
+            Result := TKeyword.Create(AName, FRegistry.Count);
             FRegistry.Add(AName, Result);
         end;
     finally
@@ -80,4 +108,47 @@ begin
     end;
 end;
 
+{ TKeywordMapping }
+
+constructor TKeywordMapping<T>.Create(const AFields: TArray<TField>);
+begin
+    FFields := AFields;
+    FFirst := 0;
+    FLast := -1;
+    if Length(FFields) = 0 then
+        exit;
+
+    FFirst := FFields[0].Key.Idx;
+    FLast := FFirst;
+    for var i := 1 to High(FFields) do
+    begin
+        var idx := FFields[i].Key.Idx;
+        if FFirst > idx then
+            FFirst := idx;
+        if FLast < idx then
+            FLast := idx;
+    end;
+
+    SetLength(FMap, FLast - FFirst + 1);
+    for var i := 0 to High(FMap) do
+        FMap[i] := -1;
+    for var i := 0 to High(FFields) do
+        FMap[FFirst + FFields[i].Key.Idx] := i;
+end;
+
+function TKeywordMapping<T>.IndexOf(const Key: IKeyword): Integer;
+begin
+    var idx := Key.Idx - FFirst;
+    if (idx < 0) or (Idx > High(FMap)) then
+        exit(-1);
+
+    Result := FMap[idx];
+end;
+
+constructor TKeywordMapping<T>.TField.Create(const AKey: IKeyword; const AValue: T);
+begin
+    Key := AKey;
+    Value := AValue;
+end;
+
 end.