BaseNcodingPascal
1.0.0
Ceci est un port de basencodage vers Pascal.
Il existe des algorithmes bien connus pour le codage des données binaires, tels que des algorithmes avec un radix de puissance de 2 (base32, base64) et des algorithmes sans puissance de 2 (base85, base91).
Cette bibliothèque implémente l'algorithme pour le cas général, c'est-à-dire que l'alphabet personnalisé peut être utilisé (alphabet avec longueur personnalisée).
L'idée de l'algorithme développé est basée sur le codage de la base85, sauf que la taille du bloc n'est pas constante, mais est calculée en fonction de la longueur de l'alphabet.
### étapes de l'algorithme
Pour le calcul optimal de la taille du bloc, les considérations suivantes ont été utilisées:
Dans ce système:
Le diagramme de la taille optimale du bloc et de la dépendance à la longueur de l'alphabet a été calculé à l'aide du système ci-dessus:
On peut voir que les encodages connus de Base64, Base85, Base91 ont été développés en bons points (taille minimale du bloc avec bon rapport de compression).
Pour Bits Block to Chars Block, l'implémentation BigInteger dans ma bibliothèque Bignumber, DelphiBignumberXlib avec quelques légères modifications a été utilisée.
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.
Exemples de code ###
// 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 { $ENDIF } ;
begin
// Creates a Base32 Instance with Default Values. You can Specify your Desired
// Parameters During Creation of the Instance.
B32 := TBase32.Create();
// Accepts a String and Encodes it Internally using UTF8 as the Default Encoding
EncodedString := B32.EncodeString( ' TestValue ' );
// Accepts an Encoded String and Decodes it Internally using UTF8 as the Default Encoding
DecodedString := B32.DecodeToString(EncodedString);
// Accepts a Byte Array and Encodes it.
EncodedString := B32.Encode(TEncoding.ANSI.GetBytes( ' TestValue ' ));
// Accepts an Encoded String and Decodes it. (Returns a Byte Array)
DecodedArray := B32.Decode(EncodedString);
// Property that allows you to modifies The Encoding of the Created Instance.
B32.Encoding := TEncoding.Unicode;
// Property that allows you to get The Base Alphabets used to perform the Encoding.
BaseAlphabet := B32.Alphabet;
// Property that allows you to get The Base Char (Padder) used to perform the Encoding.
BaseSpecial := B32.Special;
// There are some other important properties but those are left for you to figure out. :)
// Also no need to "Free" the Created Instance Since it is Reference Counted.
// or for a simple one-liner to Base32 Encode a String
TBaseFactory.CreateBase32().EncodeString( ' Fish ' );
end ;Tests unitaires.
Pour exécuter des tests unitaires,
Pour FPC 3.0.0 et plus
Simply compile and run "BaseNcoding.Tests" project in "FreePascal.Tests" Folder.
Pour Delphi 2010 et au-dessus
Méthode un (en utilisant Dunit Test Runner)
To Build and Run the Unit Tests For Delphi 10 Seattle (should be similar for
other versions)
1). Open Project Options of Unit Test (BaseNcoding.Tests) in "Delphi.Tests" Folder.
2). Change Target to All Configurations (Or "Base" In Older Delphi Versions.)
3). In Output directory add ".$(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.
Méthode deux (à l'aide de Tessindsight) (préféré).
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.
###Licence
Ce "logiciel" est sous MIT License (MIT) .
1MhFfW7tDuEHQSgie65uJcAfJgCNchGeKf0x6c1DC21aeC49A822A4f1E3bf07c623C2C1978a98345367-40###Conclusion
Un merci spécial à Ivan Kochurkin pour cette superbe bibliothèque.
