flickr.Dictionary.sorting.pas

// Copyright (c) 2015, Jordi Corbilla
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// - Redistributions of source code must retain the above copyright notice,
// this list of conditions and the following disclaimer.
// - Redistributions in binary form must reproduce the above copyright notice,
// this list of conditions and the following disclaimer in the documentation
// and/or other materials provided with the distribution.
// - Neither the name of this library nor the names of its contributors may be
// used to endorse or promote products derived from this software without
// specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
// POSSIBILITY OF SUCH DAMAGE.

unit flickr.Dictionary.sorting;

interface

uses
  Generics.collections, Generics.defaults;

type
  TDictionaryCompareString = class(TComparer<String>)
  public
    function Compare(const Left, Right: String): integer; override;
  end;

  TDictionarySorting = class(TObject)
    class function getSortedKey(Dictionary: TDictionary<string, string>) : TArray<string>;
  end;

implementation

uses
  SysUtils;

{ TDictionarySorting }

class function TDictionarySorting.getSortedKey(Dictionary: TDictionary<string, string>): TArray<string>;
var
  IStringComparer: TComparer<String>;
  sortedArray: TArray<String>;
  dictionaryCollection: TDictionary<String, String>.TKeyCollection;
begin
  IStringComparer := TDictionaryCompareString.Create();
  dictionaryCollection := TDictionary<String, String>.TKeyCollection.Create(Dictionary);
  try
    sortedArray := dictionaryCollection.ToArray;
    TArray.Sort<String>(sortedArray, IStringComparer);
  finally
    dictionaryCollection.Free;
    IStringComparer.Free;
  end;

  Result := sortedArray;
end;

{ TDictionaryCompareString }

function TDictionaryCompareString.Compare(const Left, Right: String): integer;
begin
  Result := CompareText(Left, Right);
end;

end.