mirror of
https://github.com/danieleteti/delphimvcframework.git
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143 lines
3.2 KiB
ObjectPascal
143 lines
3.2 KiB
ObjectPascal
// *************************************************************************** }
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//
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// Delphi MVC Framework
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//
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// Copyright (c) 2010-2020 Daniele Teti and the DMVCFramework Team
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//
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// https://github.com/danieleteti/delphimvcframework
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//
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// ***************************************************************************
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//
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// ***************************************************************************
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unit MVCFramework.LRUCache;
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interface
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uses
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System.SysUtils, System.Generics.Collections;
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type
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TMVCLRUCache<T: class> = class
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private
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type
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TMVCLRUCacheItem = class
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public
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Key: string;
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Value: T;
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constructor Create(const Key: string; const Item: T);
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destructor Destroy; override;
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end;
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var
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fCache: TObjectList<TMVCLRUCacheItem>;
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fCapacity: Integer;
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public
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constructor Create(const Capacity: Integer);
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virtual;
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destructor Destroy;
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override;
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function Contains(const Key: string; out ItemIndex: UInt64): Boolean;
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procedure Put(const Key: string; const Item: T);
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function TryGet(const Key: string; out Item: T): Boolean;
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procedure Clear;
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end;
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implementation
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{ TMVCLRUCache }
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procedure TMVCLRUCache<T>.Clear;
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begin
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fCache.Clear;
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end;
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function TMVCLRUCache<T>.Contains(const Key: string; out ItemIndex: UInt64): Boolean;
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var
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I: Integer;
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begin
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Result := False;
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for I := 0 to fCache.Count - 1 do
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begin
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if Key = fCache[I].Key then
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begin
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ItemIndex := I;
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Exit(True);
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end;
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end;
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end;
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constructor TMVCLRUCache<T>.Create(const Capacity: Integer);
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begin
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inherited Create;
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fCapacity := Capacity;
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fCache := TObjectList<TMVCLRUCacheItem>.Create(True);
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end;
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destructor TMVCLRUCache<T>.Destroy;
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begin
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fCache.Free;
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inherited;
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end;
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procedure TMVCLRUCache<T>.Put(const Key: string; const Item: T);
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begin
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if fCache.Count = fCapacity then
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begin
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fCache.Delete(fCache.Count - 1);
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end;
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fCache.Insert(0, TMVCLRUCacheItem.Create(Key, Item));
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end;
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function TMVCLRUCache<T>.TryGet(const Key: string; out Item: T): Boolean;
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var
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lItemIndex: UInt64;
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lCacheItem: TMVCLRUCacheItem;
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begin
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Result := contains(Key, lItemIndex);
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if Result { and (lItemIndex <> 0) } then
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begin
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if lItemIndex = 0 then
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begin
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lCacheItem := fCache[0];
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end
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else
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begin
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lCacheItem := fCache.Extract(fCache[lItemIndex]);
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fCache.Insert(0, lCacheItem);
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end;
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Item := lCacheItem.Value;
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end;
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end;
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{ TMVCLRUCache<T>.TMVCLRUCacheItem<T> }
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constructor TMVCLRUCache<T>.TMVCLRUCacheItem.Create(const Key: string;
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const Item: T);
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begin
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inherited Create;
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Self.Key := Key;
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Self.Value := Item;
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end;
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destructor TMVCLRUCache<T>.TMVCLRUCacheItem.Destroy;
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begin
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Value.Free;
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Value := nil;
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inherited;
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end;
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end.
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