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Jeroen W. Pluimers on .NET, C#, Delphi, databases, and personal interests

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Archive for the ‘UTF-8’ Category

Default XML encoding is UTF-8 (or better: utf-8). If it contains other byte sequences, this is an error.

Posted by jpluimers on 2021/01/21

I should have had the below answer when writing about StUF – receiving data from a provider where UTF-8 is in fact ISO-8859.

A while ago, a co-worker did not believe when I told that default XML encoding really is UTF-8 (and tried to force it to utf-8), and that if the content had byte sequences different from the (either specified or default) encoding, it was a problem.

I though I blogged about the default, and where to find it, but apparently, I did not.

My blog had (and has <g>) a truckload of articles mentioning UTF-8, less articles containing UTF-8, encoding and xml, but the ones having UTF-8, default, encoding and xml did not actually tell about a standard that really defines XML uses UTF-8 as default encoding when there is no other encoding information – like BOM (byte order mark), HTTP, or MIME encoding) available.

W3C indeed specifies it. [WayBack] utf 8 – How default is the default encoding (UTF-8) in the XML Declaration? – Stack Overflow has a summary (thanks James Holderness!):

The Short Answer

Under the very specific circumstances of a UTF-8 encoded document with no external encoding information (which I understand from the comments is what you’re interested in), there is no difference between the two declarations.

The long answer is far more interesting though.

and an elaboration:

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Posted in Development, Encoding, Software Development, UTF-8, UTF8, XML, XML/XSD | Leave a Comment »

Bad surprise of the day: SysUtils.TEncoding in XE2+ defaults to ANSI, while in XE it defaulted to UTF-8.

Posted by jpluimers on 2020/03/11

Bad surprise of the day: SysUtils.TEncoding in XE2+ defaults to ANSI, while in XE it defaulted to UTF-8 .Among other things this means that TStringList… – Eric Grange – Google+

Source: Bad surprise of the day: SysUtils.TEncoding in XE2+ defaults to ANSI, while i…


Eric Grange's profile photo

+Stefan Glienke Indeed, you’re right. The issue must be deeper somewhere. Don’t have time to investigate too much, I’m bypassing the RTL now (also have to work around the limitation that for utf-8 the TEncoding.GetString method returns an empty string if one character in the buffer isn’t utf-8)

Asbjørn Heid's profile photo

I wouldn’t trust the RTL at all with loading non-ascii text, we’ve had it hang on invalid UTF-8 codes more than once.


Posted in Ansi, Delphi, Development, Encoding, Software Development, UTF-8, UTF8 | Leave a Comment »

Which encoding failure did encode “vóór” into “v3/43/4r”? – Stack Overflow

Posted by jpluimers on 2020/02/24

From quite some time ago, but still very relevant as encoding issues keep occurring:

A while ago, I saw the text “v3/43/4r” in a document.I know it comes from “vóór” (the acute accent emphasises in Dutch), and wonder which encoding failure was applied to get this wrong.

Source: [WayBackWhich encoding failure did encode “vóór” into “v3/43/4r”? – Stack Overflow

From the [WayBack] answer by rodrigo:

  • ó: is U+00F3, and occupies the same codepoint (0xF3) in a lot of different encodings (most ISO-8859-* and most western Windows-*).
  • In CP850 the codepint 0xF3 is ¾ (U+00BE), that is the three-quarters character. It is the same in other, less used, codepages (CP775, CP856, CP857, CP858).
  • The ¾ is sometimes transliterated to 3/4 when the character is not directly available.

And there you are! “vóór” -> “v¾¾r” -> “v3/43/4r”.

The first part (ó -> ¾) is the usual corruption of ANSI vs. OEM codepages in the Western Windows versions (in my country ANSI=Windows-1252, OEM=CP850). You can see it easily creating a file with NOTEPAD, writing vóór and dumping it in a command prompt with type.


Posted in CP850, Development, Encoding, Software Development, UTF-8, UTF8, Windows-1252 | Leave a Comment »

Delphi, decoding files to strings and finding line endings: some links, some history on Windows NT and UTF/UCS encodings

Posted by jpluimers on 2019/12/31

A while back there were a few G+ threads sprouted by David Heffernan on decoding big files into line-ending splitted strings:

Code comparison:


with open(filename, 'r', encoding='utf-16-le') as f:
  for line in f:


for Line in TLineReader.FromFile(filename, TEncoding.Unicode) do

This spurred some nice observations and unfounded statements on which encodings should be used, so I posted a bit of history that is included below.

Some tips and observations from the links:

  • Good old text files are not “good” with Unicode support, neither are TextFile Device Drivers; nobody has written a driver supporting a wide range of encodings as of yet.
  • Good old text files are slow as well, even with a changed SetTextBuffer
  • When using the TStreamReader, the decoding takes much more time than the actual reading, which means that [WayBack] Faster FileStream with TBufferedFileStream • DelphiABall does not help much
  • TStringList.LoadFromFile, though fast, is a memory allocation dork and has limits on string size
  • Delphi RTL code is not what it used to be: pre-Delphi Unicode RTL code is of far better quality than Delphi 2009 and up RTL code
  • Supporting various encodings is important
  • EBCDIC days: three kinds of spaces, two kinds of hyphens, multiple codepages
  • Strings are just that: strings. It’s about the encoding from/to the file that needs to be optimal.
  • When processing large files, caching only makes sense when the file fits in memory. Otherwise caching just adds overhead.
  • On Windows, if you read a big text file into memory, open the file in “sequential read” mode, to disable caching. Use the FILE_FLAG_SEQUENTIAL_SCAN flag under Windows, as stated at [WayBack] How do FILE_FLAG_SEQUENTIAL_SCAN and FILE_FLAG_RANDOM_ACCESS affect how the operating system treats my file? – The Old New Thing
  • Python string reading depends on the way you read files (ASCII or Unicode); see [WayBack] unicode – Python codecs line ending – Stack Overflow

Though TLineReader is not part of the RTL, I think it is from [WayBack] For-in Enumeration – ADUG.

Encodings in use

It doesn’t help that on the Windows Console, various encodings are used:

Good reading here is [WayBack] c++ – What unicode encoding (UTF-8, UTF-16, other) does Windows use for its Unicode data types? – Stack Overflow

Encoding history

+A. Bouchez I’m with +David Heffernan here:

At its release in 1993, Windows NT was very early in supporting Unicode. Development of Windows NT started in 1990 where they opted for UCS-2 having 2 bytes per character and had a non-required annex on UTF-1.

UTF-1 – that later evolved into UTF-8 – did not even exist at that time. Even UCS-2 was still young: it got designed in 1989. UTF-8 was outlined late 1992 and became a standard in 1993

Some references:


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Posted in Delphi, Development, Encoding, PowerShell, PowerShell, Python, Scripting, Software Development, The Old New Thing, Unicode, UTF-16, UTF-8, Windows Development | Leave a Comment »

Delphi Galileo IDE (version 8 and up): Force files to be saved as UTF8 – The Oracle at Delphi

Posted by jpluimers on 2019/07/04

Though formatting mangled the registry key to add, the article is interesting: since 2003 (C# Builder 1), you can force the IDE to always save files as UTF8 which should alleviate a lot of encoding problems.

It beats me why this isn’t the default setting, but below is an example .reg file for Delphi 8 which should be easily transformed to more recent Delphi versions:

Windows Registry Editor Version 5.00

So basically (if formatting is kept), you browse to this key (replace Borland with the company for your specific Delphi version, and replace 2.0 by your IDE version):


Then you add a new string value named DefaultFileFilter with value Borland.FileFilter.UTF8ToUTF8

More background [WayBack] The Oracle at Delphi: More IDE secrets – UTF8 and the Editor

The unmangled registry key (and more tips) was from [WayBackBSC Polska: Hidden possibilities of Delphi 8.

Get the list of HKEY_CURRENT_USER paths for your Delphi version at Update to List-Delphi-Installed-Packages.ps1 shows HKCU/HKLM keys and doesn’t truncated fields any more.


Via: [WayBack] Is there any way (IDE expert?) to automatic set encoding of each PAS file in UTF-8 instead of ANSI? – Jacek Laskowski – Google+

Posted in Delphi, Development, Encoding, Software Development, UTF-8, UTF8 | 1 Comment »

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