Difference between revisions of "UTF8 string class/en"

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{{UTF8 String Class}}
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{{UTF8 string class}}
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__TOC__
  
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{{UTF8 String Class en}}
 
 
== What is TbUtf8? ==
 
== What is TbUtf8? ==
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Under construction!!
 
  
 
With the library TbUtf8 you can easily change UTF8 Strings.
 
With the library TbUtf8 you can easily change UTF8 Strings.
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=== Solution ===
 
=== Solution ===
 
With TbUtf8 you can now easily change and search UTF8 strings with special and combined characters, such as "üäößẶặǺǻǼǽǞǟǍǎḂḃÞþÇçĆćĊċ...". Essentially, the library consists of a UTF8 string class (TIbUtf8).
 
With TbUtf8 you can now easily change and search UTF8 strings with special and combined characters, such as "üäößẶặǺǻǼǽǞǟǍǎḂḃÞþÇçĆćĊċ...". Essentially, the library consists of a UTF8 string class (TIbUtf8).
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=== Benefits ===
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*TIbUtf8 is a class type of TInterfacedObject and does not need to be cleaned up with free.
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*All indexes are character based.
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*All returned characters are of type String.
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*Returns the number of characters in the string.
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*Returns the number of bytes in the string.
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*Delete characters or character groups.
 +
*Insertion of characters and character groups.
 +
*Appending characters and character groups.
 +
*Reading / writing of characters and character groups.
 +
*Read from file / write to a file.
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*Read from stream / write to a stream.
 +
 +
=== Disadvantage ===
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*Since UTF8 does not have a constant offset from character to character, searching for characters is much more complex. Iterating over the characters is about 20 times slower than with the string. (Comfort has its price)
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*Slightly more memory is required.
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=== Example ===
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<syntaxhighlight lang="pascal">
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proceudre Demo01: Boolean;
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var
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  u: IbUtf8;
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  i: Integer;
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begin
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  u:= TIbUtf8.Create('Thömäß');
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  for i:= 1 to u.NumberOfChars do begin
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    case u.Chars[i] of
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      'ö': u.Chars[i]:= 'o';
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      'ä': u.Chars[i]:= 'a';
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      'ß': u.Chars[i]:= 's';
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    end;
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  end;
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  if u.Text = 'Thomas' then begin
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    WriteLn('That's right!');
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  end;
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end;
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</syntaxhighlight>
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== DownLoad ==
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* GitLab FpTuxe/TbUtf8 repository
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[https://gitlab.com/FpTuxe/tbutf8 FpTuxe/TbUtf8]
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* Git clone
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<syntaxhighlight lang="bash">
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git clone https://gitlab.com/FpTuxe/tbutf8.git
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</syntaxhighlight>
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== Installation ==
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;Variant  1
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:Start Lazarus and open your project.
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:Lazarus->File->Open your workspace/tbutf8/src/tb_utf8.pas
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:Lazarus->Project->Add Editor File to Project
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;Variant  2
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:Start Lazarus and open your project.
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:Lazarus->Package->Open Package File (.lpk) your workspace/tbutf8/src/tbutf8.lpk
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:Now, click Use->Add to Project
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:Close then Package window.
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== Functional Description ==
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The functional description, you can found under the project folder "doc/".
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 +
 +
[[Category:Unicode]]

Latest revision as of 17:36, 23 January 2022

│ English (en) │

What is TbUtf8?

With the library TbUtf8 you can easily change UTF8 Strings.

Problem

With Lazarus (Free Pascal) the string UTF8 encoded. However, the "String" type is nothing more than a dynamic byte array. Length returns the number of bytes in the array but not the number of characters. With UTF8, a character can be 4 bytes long and even 7 bytes with combined characters. An example should illustrate this. 'Thomas' 6 characters, 6 bytes in size. 'Thömäs' 6 characters, 8 bytes in size.

Solution

With TbUtf8 you can now easily change and search UTF8 strings with special and combined characters, such as "üäößẶặǺǻǼǽǞǟǍǎḂḃÞþÇçĆćĊċ...". Essentially, the library consists of a UTF8 string class (TIbUtf8).

Benefits

  • TIbUtf8 is a class type of TInterfacedObject and does not need to be cleaned up with free.
  • All indexes are character based.
  • All returned characters are of type String.
  • Returns the number of characters in the string.
  • Returns the number of bytes in the string.
  • Delete characters or character groups.
  • Insertion of characters and character groups.
  • Appending characters and character groups.
  • Reading / writing of characters and character groups.
  • Read from file / write to a file.
  • Read from stream / write to a stream.

Disadvantage

  • Since UTF8 does not have a constant offset from character to character, searching for characters is much more complex. Iterating over the characters is about 20 times slower than with the string. (Comfort has its price)
  • Slightly more memory is required.


Example

proceudre Demo01: Boolean;
var
  u: IbUtf8;
  i: Integer;
begin
  u:= TIbUtf8.Create('Thömäß');
  for i:= 1 to u.NumberOfChars do begin
    case u.Chars[i] of
      'ö': u.Chars[i]:= 'o';
      'ä': u.Chars[i]:= 'a';
      'ß': u.Chars[i]:= 's';
    end;
  end;
  if u.Text = 'Thomas' then begin
    WriteLn('That's right!');
  end;
end;

DownLoad

  • GitLab FpTuxe/TbUtf8 repository
FpTuxe/TbUtf8
  • Git clone
git clone https://gitlab.com/FpTuxe/tbutf8.git

Installation

Variant 1
Start Lazarus and open your project.
Lazarus->File->Open your workspace/tbutf8/src/tb_utf8.pas
Lazarus->Project->Add Editor File to Project
Variant 2
Start Lazarus and open your project.
Lazarus->Package->Open Package File (.lpk) your workspace/tbutf8/src/tbutf8.lpk
Now, click Use->Add to Project
Close then Package window.

Functional Description

The functional description, you can found under the project folder "doc/".

Retrieved from "http://wiki.freepascal.org/index.php?title=UTF8_string_class/en&oldid=149591"