Unduh BaseNcodingPascal - Unduh Kode Sumber BaseNcodingPascal

BaseNcodingPascal

Kode sumber Delphi

1.0.0

Unduh

Basencodingpascal

Ini adalah pelabuhan basencoding ke Pascal.

Ada algoritma terkenal untuk data biner ke pengkodean string, seperti algoritma dengan radix daya 2 (base32, base64) dan algoritma tanpa daya 2 (base85, base91).

Perpustakaan ini mengimplementasikan algoritma untuk kasus umum, yaitu, alfabet khusus dapat digunakan (alfabet dengan panjang khusus).

Gagasan algoritma yang dikembangkan didasarkan pada pengkodean base85, kecuali bahwa ukuran blok tidak konstan, tetapi dihitung tergantung pada panjang alfabet.

### Langkah -langkah algoritma

Perhitungan ukuran blok dalam bit dan chars.
Konversi string input ke array byte (menggunakan pengkodean UTF8).
Membagi array byte pada kelompok n-bit.
Percakapan setiap kelompok ke radix n.
Bit ekor pemrosesan.

Untuk perhitungan ukuran blok yang optimal, pertimbangan berikut telah digunakan:

Dalam sistem ini:

A - Panjang alfabet a .
K - Hitungan Chars Pengkodean.
B - Basis radix satu digit (2 dalam banyak kasus).
n - Bit dihitung dalam radix B untuk representasi k chars dari alfabet a .
R - rasio kompresi (lebih besar lebih baik).
MBC - Max Block Bits Count.
⌊X⌋ - Integer terbesar tidak lebih besar dari X (lantai).
⌈X⌉ - Integer terkecil tidak kurang dari X (langit -langit).

Diagram ukuran blok optimal dan ketergantungan panjang alfabet telah dihitung dengan bantuan sistem di atas:

Orang dapat melihat bahwa encodings Base64, Base85, Base91 yang diketahui telah dikembangkan dalam poin yang baik (ukuran blok minimal dengan rasio kompresi yang baik).

Untuk Blok Bit ke Blok Chars, implementasi BigInteger di perpustakaan Bignumber saya, Delphibignumberxlib dengan beberapa modifikasi sedikit digunakan.

Porting guidelines:

 1. All file names (units) are the same, but with a "u" prefix. 
2. Some variables were closely named. 
3. Some functions were written by me because I could not find a Delphi/
   FreePascal Equivalent of the C# function used, in the RTL or for Backwards
   Compatibility with older Unicode versions of Delphi or FreePascal.

Hints about the code:

 1.  Multi-condition "for" loops and loops where iterator gets changed inside 
  the loop were converted to while loops. 

2.  Log method (Delphi/FreePascal Equivalent "LogN"), two arguments (a, newBase) needed to be 
    swapped in Delphi/FreePascal.   

3.  This Library was written with (Delphi 10 Seattle Update 1) but will 
    work fine with anything from Delphi 2010 and FreePascal 3.0.0 Upwards.

4.  "Parallel version" was implemented using PPL (Parallel Programming Library) 
     but will only work in Delphi XE7 Upwards.

5.  This Library was written with the Object Oriented Paradigm (Class-Based) but 
    implements memory management through reference counting with the help of 
    Interfaces (that is, created objects or class instances are "freed" once they 
    go out of scope).

6. If you are working with FreePascal in which the String and Char types are Mapped 
   to "AnsiString" and "AnsiChar" by Default, you could "remap" them to "UnicodeString" 
   and "UnicodeChar" by declaring "{$mode delphiunicode}" at the top of your unit 
   excluding the ("") symbols.

Common pitfalls during porting:

 1. Calling Log methods without swapping arguments places.
2. Writing for .. to .. do loop instead of for .. downto .. do in rare cases.
3. Differences in Order of Operator Precedence between C# and Pascal.

Contoh Kode ###

     // Here is a Little Snippet showing Usage for Base32 Operations.  
    uses
      SysUtils, BcpBase32, BcpIBaseInterfaces, BcpBaseFactory;

      procedure TForm1.Button1Click (Sender: TObject);
	var
	  B32: IBase32;
	  EncodedString, DecodedString, BaseAlphabet: { $IFDEF FPC } UnicodeString { $ELSE } String { $ENDIF } ;
	  DecodedArray: TBytes;
	  BaseSpecial: { $IFDEF FPC } UnicodeChar { $ELSE } Char { $ENDIF } ;
	begin
	  // Creates a Base32 Instance with Default Values. You can Specify your Desired 
	  // Parameters During Creation of the Instance.
	  B32 := TBase32.Create();
	  // Accepts a String and Encodes it Internally using UTF8 as the Default Encoding
	  EncodedString := B32.EncodeString( ' TestValue ' );
	  // Accepts an Encoded String and Decodes it Internally using UTF8 as the Default Encoding
	  DecodedString := B32.DecodeToString(EncodedString);
	  // Accepts a Byte Array and Encodes it.
	  EncodedString := B32.Encode(TEncoding.ANSI.GetBytes( ' TestValue ' ));
	  // Accepts an Encoded String and Decodes it. (Returns a Byte Array)
	  DecodedArray := B32.Decode(EncodedString);
	  // Property that allows you to modifies The Encoding of the Created Instance.
	  B32.Encoding := TEncoding.Unicode;
	  // Property that allows you to get The Base Alphabets used to perform the Encoding.
	  BaseAlphabet := B32.Alphabet;
	  // Property that allows you to get The Base Char (Padder) used to perform the Encoding.
	  BaseSpecial := B32.Special;
	 // There are some other important properties but those are left for you to figure out. :)
	 // Also no need to "Free" the Created Instance Since it is Reference Counted.
	// or for a simple one-liner to Base32 Encode a String
	  TBaseFactory.CreateBase32().EncodeString( ' Fish ' );
    end ;

Tes unit.

Untuk menjalankan tes unit,

Untuk FPC 3.0.0 dan di atas

 Simply compile and run "BaseNcoding.Tests" project in "FreePascal.Tests" Folder.

Untuk Delphi 2010 dan di atas

Metode satu (menggunakan Dunit Test Runner)

 To Build and Run the Unit Tests For Delphi 10 Seattle (should be similar for 
 other versions)

1). Open Project Options of Unit Test (BaseNcoding.Tests) in "Delphi.Tests" Folder.

2). Change Target to All Configurations (Or "Base" In Older Delphi Versions.)

3). In Output directory add ".$(Platform)$(Config)" without the quotes.

4). In Search path add "$(BDS)SourceDUnitsrc" without the quotes.

5). In Unit output directory add "." without the quotes.

6). In Unit scope names (If Available), Delete "DUnitX" from the List.

Press Ok and save, then build and run.

Metode dua (menggunakan testInsight) (lebih disukai).

 1). Download and Install TestInsight.

2). Open Project Options of Unit Test (BaseNcoding.Tests.TestInsight) in "Delphi.Tests" 
    Folder. 

3). Change Target to All Configurations (Or "Base" In Older Delphi Versions.)

4). In Unit scope names (If Available), Delete "DUnitX" from the List.

5). To Use TestInsight, right-click on the project, then select 
	"Enable for TestInsight" or "TestInsight Project".
    Save Project then Build and Run Test Project through TestInsight.

###Lisensi

"Perangkat lunak" ini dilisensikan di bawah MIT License (MIT) .