Итак, пусть у нас в некоторой директории находится файл SomeFile, сделаем так, чтобы при добавлении следующего файла с именем SomeFile, в директории оказался файл SomeFile(1), SomeFile(2), SomeFile(3). При отсутствии этого файла в директорию копируется просто файл. Данная задача возникла в результате разработки решения для передачи файлов по HTTP протоколу. Нужно было сделать так, чтобы при каждой передаче файл в обязательном порядке копировался и сохранялся под новым именем в любом случае, даже если он там уже есть. Не перезаписывал существующий, а создавал новый, с каким-то другим именем.
Первоначально задача показалась мне тривиальной, пока я не начал ее решать. Впоследствии я понял, что там множество других маленьких задач. Вот что у меня получилось.
Основная функция
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class function TCreateUniqueName.CreateUniqueNameAddingNumber( ANamesToCompare: TStringList; ANameThatShouldBeUnique: String): String; begin Result:=ANameThatShouldBeUnique; if ANamesToCompare.IndexOf(ANameThatShouldBeUnique)=-1 then begin Result:=ANameThatShouldBeUnique; // Already Unique Exit; end else repeat Result:=AddNumberOnTheEnd(Result); until ANamesToCompare.IndexOf(Result)=-1 ; end; |
Здесь у нас список имен, с которыми нужно сравнивать, это имена из директории. А также само имя, которое должно быть уникальным.
Эта функция опирается на следующую – добавление номера в скобки на конце
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class function TCreateUniqueName.AddNumberOnTheEnd(ANameWithNumberOnTheEnd: String): String; var SplittedString:TArray<String>; i: integer; NameWithoutExtension:string; NumberInTheEnd: Integer; SubStringWithoutLastBrackets: string; StringWithoutExtension:String; Extension: string; StringWithoutBracketsInTheEnd: string; begin // Check of Uniquiness StringWithoutExtension:=GetStringWithoutExtension(ANameWithNumberOnTheEnd,Extension); if GetNumberInBracketsFromTheEnd(ANameWithNumberOnTheEnd)='' then begin Result:=StringWithoutExtension+'(1)'; // adding first number if Extension<>'' then Result:=Result+'.'+Extension; end else begin NumberInTheEnd:=GetNumberInBracketsFromTheEnd(StringWithoutExtension).ToInteger; if IsValueInBracketsAtEndOfString(StringWithoutExtension,NumberInTheEnd.ToString()) then begin StringWithoutBracketsInTheEnd:= GetSubStringWithoutLastBracketsInTheEnd(StringWithoutExtension,NumberInTheEnd.ToString()); NumberInTheEnd:=NumberInTheEnd+1; Result:=StringWithoutBracketsInTheEnd+'('+NumberInTheEnd.ToString()+')'; end else begin Result:=ANameWithNumberOnTheEnd+'(1)'; // adding first number end; if Extension<>'' then Result:=Result+'.'+Extension; end; end; |
Нам также нужно научиться выделять строку без расширения
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class function TCreateUniqueName.GetStringWithoutExtension(AFileName: string; var Extension:String ): string; var SplittedString:TArray<String>; i: Integer; begin SplittedString:=AFileName.Split(['.']); // if some Extension is... if High(SplittedString)>=1 then begin //Gather all splitted elements except extension Result:=''; for i := 0 to High(SplittedString)-1 do begin Result:=Result+SplittedString[i]; end; // Remembering Extension; Extension:=SplittedString[High(SplittedString)]; end else begin Result:=AFileName; Extension:=''; end; end; |
Нам также нужно научиться выделять строку без последних скобок с номером. Это можно сделать простым выделением подстроки
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class function TCreateUniqueName.GetSubStringWithoutLastBracketsInTheEnd(ASomeString: string; AValueInBrackets:String ): String; begin // if (ASomeString.Length>0) and (AValueInBrackets.Length>0) and (ASomeString.Length-AValueInBrackets.Length>=3) // 3 means (1) for example then Result:=ASomeString. Substring(0,ASomeString.Length-AValueInBrackets.Length-2);// -2 means brackets around value for ex. (1) end; |
И последнее -научиться вытаскивать номер из скобок на конце. Тут помогли регулярные выражения
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class function TCreateUniqueNameServer.GetNumberInBracketsFromTheEnd(AFileName: string ): string; var RegEx:TRegEx; M:TMatchCollection; s:String; NumberInBrackets:String; RegEx2:TRegEx; M2:TMatchCollection; begin Result:=''; RegEx:=TRegEx.Create('\([\d]+\)'); // Extracting (1) from SomeFile(1) - will receive (1) M:=RegEx.Matches(AFileName); if M.Count>0 then begin NumberInBrackets:=M.Item[M.Count-1].Value; // Extracting Last One end; RegEx2:=TRegEx.Create('[\d]+'); // Extracting 1 from (1) M2:=RegEx2.Matches(NumberInBrackets); if M2.Count>0 then begin Result:=M2.Item[M.Count-1].Value; // Extracting Last One end; end; |
ЮНИТ ПОЛНОСТЬЮ
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unit uUniShopMilk.CreateUniqueName; {< this unit contains methods that will Create Unique Name} interface uses System.SysUtils, System.Classes, vcl.dialogs, System.RegularExpressions,uSortStringList,StrUtils; type TUniShopMilkCreateUniqueName = class(TDataModule) private { Private declarations } public { Public declarations } class function CreateUniqueNameAddingGUID( FileName:string; MaxOriginNameLength:Integer ):string; {< CreateUniqueNameAddingGUID - all clear from the name. This is class function} class function AddNumberOnTheEnd(ANameWithNumberOnTheEnd:String):String; class function CreateUniqueNameAddingNumber(ANamesToCompare:TStringList; ANameThatShouldBeUnique:String):String; {< this method will Create Unique Name like SomeName(1),SomeName(2), Etc.} class function IsFileNameUnique(ANameThatShouldBeUnique:String; AAllNamesToCompareSL:TStringList):boolean; {< this method will Create Unique Name like SomeName(1),SomeName(2), Etc.} class function AddParamAndValueToName(FileName, Param, Value: string): string; static; {<this will add Param=Value to someName } class function GetParamValueFromFileName(FileName: string; const ParamName: string):string; static; {<this will get ParamValue from Name like Param=Value } class function GetNumberInBracketsFromTheEnd(AFileName: string): string; static; class function FindAllOffsetsOfSubstrings(ASomeString: string; ASomeSubString:String): TStringList; static; class function GetSubStringWithoutLastBracketsInTheEnd(ASomeString, AValueInBrackets: String): String; static; class function IsValueInBracketsAtEndOfString(ASomeString, AValueInBrackets: String): Boolean; static; class function GetStringWithoutExtension(AFileName: string; var Extension:String): string; static; end; //var // CreateUniqueName: TCreateUniqueName; implementation {%CLASSGROUP 'Vcl.Controls.TControl'} {$R *.dfm} { TCreateUniqueName } {Creating New Unique Name with a rest of old name, using GUID} class function TUniShopMilkCreateUniqueName.CreateUniqueNameAddingGUID(FileName: string; MaxOriginNameLength: Integer): string; var Extension:string; SplittedString: TArray<String>; SomeStringToChange: string; newguid:tguid; i: Integer; FileNameTemp:string; begin //Checks if FileName='' then Exit; //if MaxOriginNameLength=0 then exit; // if MaxOriginNameLength=0 will be only GUID as a result //1--------- First of all we need to extract extension if it is SplittedString:=FileName.Split(['.']); //we suppose that extensions are symbols after last '.', so... // if FileName has extension like 'SomeFileName.exe' if Length(SplittedString)>0 //1 and more, for example somename.ext [somename,ext] then begin Extension:=SplittedString[ High(SplittedString) ]; //Lets join everything except extension for i := Low(SplittedString) to High(SplittedString)-1 do begin if i=0 then SomeStringToChange:=SomeStringToChange+SplittedString[i] else SomeStringToChange:=SomeStringToChange+'.'+SplittedString[i]; end; //Cutting name up to the MaxOriginNameLength if Length( SomeStringToChange )> MaxOriginNameLength then SomeStringToChange:=SomeStringToChange.Substring(0,MaxOriginNameLength); //Adding GUID Createguid(newguid); SomeStringToChange:=SomeStringToChange+newguid.ToString; // Joining Extension SomeStringToChange:=SomeStringToChange+'.'+Extension; Result:=SomeStringToChange; end else // if FileName without Extension like 'SomeFileName' if Length(SplittedString)=0 then begin FileNameTemp:=FileName; //Cutting name up to the MaxOriginNameLength if Length( FileNameTemp )> MaxOriginNameLength then FileNameTemp:=FileNameTemp.Substring(0,MaxOriginNameLength); //Adding GUID Createguid(newguid); FileNameTemp:=FileNameTemp+newguid.ToString; Result:=FileNameTemp; end; //ShowMessage(Result); end; class function TUniShopMilkCreateUniqueName.CreateUniqueNameAddingNumber( ANamesToCompare: TStringList; ANameThatShouldBeUnique: String): String; begin Result:=ANameThatShouldBeUnique; if ANamesToCompare.IndexOf(ANameThatShouldBeUnique)=-1 then begin Result:=ANameThatShouldBeUnique; // Already Unique Exit; end else repeat Result:=AddNumberOnTheEnd(Result); until ANamesToCompare.IndexOf(Result)=-1 ; end; class function TUniShopMilkCreateUniqueName.AddNumberOnTheEnd(ANameWithNumberOnTheEnd: String): String; var SplittedString:TArray<String>; i: integer; NameWithoutExtension:string; NumberInTheEnd: Integer; SubStringWithoutLastBrackets: string; StringWithoutExtension:String; Extension: string; StringWithoutBracketsInTheEnd: string; begin // Check of Uniquiness StringWithoutExtension:=GetStringWithoutExtension(ANameWithNumberOnTheEnd,Extension); if GetNumberInBracketsFromTheEnd(ANameWithNumberOnTheEnd)='' then begin Result:=StringWithoutExtension+'(1)'; // adding first number if Extension<>'' then Result:=Result+'.'+Extension; end else begin NumberInTheEnd:=GetNumberInBracketsFromTheEnd(StringWithoutExtension).ToInteger; if IsValueInBracketsAtEndOfString(StringWithoutExtension,NumberInTheEnd.ToString()) then begin StringWithoutBracketsInTheEnd:= GetSubStringWithoutLastBracketsInTheEnd(StringWithoutExtension,NumberInTheEnd.ToString()); NumberInTheEnd:=NumberInTheEnd+1; Result:=StringWithoutBracketsInTheEnd+'('+NumberInTheEnd.ToString()+')'; end else begin Result:=ANameWithNumberOnTheEnd+'(1)'; // adding first number end; if Extension<>'' then Result:=Result+'.'+Extension; end; end; class function TUniShopMilkCreateUniqueName.GetStringWithoutExtension(AFileName: string; var Extension:String ): string; var SplittedString:TArray<String>; i: Integer; begin SplittedString:=AFileName.Split(['.']); // if some Extension is... if High(SplittedString)>=1 then begin //Gather all splitted elements except extension Result:=''; for i := 0 to High(SplittedString)-1 do begin Result:=Result+SplittedString[i]; end; // Remembering Extension; Extension:=SplittedString[High(SplittedString)]; end else begin Result:=AFileName; Extension:=''; end; end; class function TUniShopMilkCreateUniqueName.GetNumberInBracketsFromTheEnd(AFileName: string ): string; var RegEx:TRegEx; M:TMatchCollection; s:String; NumberInBrackets:String; RegEx2:TRegEx; M2:TMatchCollection; begin Result:=''; RegEx:=TRegEx.Create('\([\d]+\)'); // Extracting (1) from SomeFile(1) - will receive (1) M:=RegEx.Matches(AFileName); if M.Count>0 then begin NumberInBrackets:=M.Item[M.Count-1].Value; // Extracting Last One end; RegEx2:=TRegEx.Create('[\d]+'); // Extracting 1 from (1) M2:=RegEx2.Matches(NumberInBrackets); if M2.Count>0 then begin Result:=M2.Item[M.Count-1].Value; // Extracting Last One end; end; class function TUniShopMilkCreateUniqueName.FindAllOffsetsOfSubstrings(ASomeString: string; ASomeSubString:String ): TStringList; var Len: Integer; P: Integer; begin Result:=TStringList.Create; // Len := Length(ASomeSubString); P := PosEx(ASomeSubString, ASomeString, 1); while P > 0 do begin Result.Add(P.ToString()); P := PosEx(ASomeSubString, ASomeString, P + Len); // Recursievely call this for next possible substring end; end; class function TUniShopMilkCreateUniqueName.GetSubStringWithoutLastBracketsInTheEnd(ASomeString: string; AValueInBrackets:String ): String; begin // if (ASomeString.Length>0) and (AValueInBrackets.Length>0) and (ASomeString.Length-AValueInBrackets.Length>=3) // 3 means (1) for example then Result:=ASomeString. Substring(0,ASomeString.Length-AValueInBrackets.Length-2);// -2 means brackets around value for ex. (1) end; class function TUniShopMilkCreateUniqueName. IsValueInBracketsAtEndOfString(ASomeString: string; AValueInBrackets:String ): Boolean; var ValueInBrackets:String; EndOfString:String; begin Result:=false; if ASomeString.Length>=ValueInBrackets.Length then begin ValueInBrackets:='('+AValueInBrackets+')'; EndOfString:=ASomeString.Substring(ASomeString.Length-ValueInBrackets.Length); if EndOfString=ValueInBrackets then Result:=True; end; end; // {Adding Params to FileName, so FileName.exe will be FileName{Param=Value}.exe } class function TUniShopMilkCreateUniqueName.AddParamAndValueToName(FileName: string; Param:string; Value:string ): string; var Extension:string; SplittedString: TArray<String>; SomeStringToChange:string; i: Integer; FileNameTemp:string; begin //Checks if FileName='' then Exit; //1--------- First of all we need to extract extension if it is SplittedString:=FileName.Split(['.']); //we suppose that extensions are symbols after last '.', so... // if FileName has extension like 'SomeFileName.exe' if Length(SplittedString)>1 //2 and more, for example somename.ext [somename,ext] then begin Extension:=SplittedString[ High(SplittedString) ]; //ShowMessage(Extension); // for test //2----------Now lets change previous massive Element if it is SomeStringToChange:=SplittedString[ High(SplittedString)-1 ]; //Adding Param And Value SomeStringToChange:=SomeStringToChange+'{'+Param+'='+Value+'}'; SplittedString[ High(SplittedString)-1 ]:=SomeStringToChange; //3-------Now our name is Unique we can join it back Result:=''; for i := Low(SplittedString) to High(SplittedString)-1 do Result:=Result+SplittedString[i]+'.'; //At last adding Extension Result:=Result+Extension; end else // if FileName without Extension like 'SomeFileName' if Length(SplittedString)=1 then begin FileNameTemp:=FileName; FileNameTemp:=FileNameTemp+'{'+Param+'='+Value+'}'; Result:=FileNameTemp; end; //ShowMessage(Result); //for test end; {Get Param Value from FileName} class function TUniShopMilkCreateUniqueName.GetParamValueFromFileName(FileName: string; const ParamName:string):string; var RegEx:TRegEx; M: TMatchCollection; M2: TMatchCollection; M3: TMatchCollection; begin Result:=''; M:=RegEx.Matches( FileName ,'{'+ParamName+'=[\w\d]*}');//chunkNumber=[\w\d]*[\d]\b //chunkNumber=[\w]*[\d]\b if M.Count>0 then M2:=RegEx.Matches( M.Item[M.Count-1].Value ,'=[\w\d]*'); if M2.Count>0 then M3:=RegEx.Matches( M2.Item[M2.Count-1].Value ,'[\w\d]*'); if M3.Count>0 then Result:=M3.Item[M3.Count-1].Value; end; class function TUniShopMilkCreateUniqueName.IsFileNameUnique(ANameThatShouldBeUnique: String; AAllNamesToCompareSL: TStringList): boolean; var SplittedString:TArray<String>; i: Integer; begin Result:=false; if AAllNamesToCompareSL.IndexOf(ANameThatShouldBeUnique)=-1 then Result:=true; end; end. |