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Archive for the ‘UTF-16’ Category

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:


Read the rest of this entry »

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 »

UTF-8 support for single byte character sets is beta in Windows and likely breaks a lot of applications not expecting this (via Unicode in Microsoft Windows: UTF-8 – Wikipedia)

Posted by jpluimers on 2018/12/04

Uh-oh: [WayBack] Unicode in Microsoft Windows: UTF-8 – Wikipedia:

Microsoft Windows has a code page designated for UTF-8code page 65001. Prior to Windows 10 insider build 17035 (November 2017),[7] it was impossible to set the locale code page to 65001, leaving this code page only available for:

  • Explicit conversion functions such as MultiByteToWideChar
  • The Win32 console command chcp 65001 to translate stdin/out between UTF-8 and UTF-16.

This means that “narrow” functions, in particular fopen, cannot be called with UTF-8 strings, and in fact there is no way to open all possible files using fopen no matter what the locale is set to and/or what bytes are put in the string, as none of the available locales can produce all possible UTF-16 characters.

On all modern non-Windows platforms, the string passed to fopen is effectively UTF-8. This produces an incompatibility between other platforms and Windows. The normal work-around is to add Windows-specific code to convert UTF-8 to UTF-16 using MultiByteToWideChar and call the “wide” function.[8] Conversion is also needed even for Windows-specific api such as SetWindowText since many applications inherently have to use UTF-8 due to its use in file formats, internet protocols, and its ability to interoperate with raw arrays of bytes.

There were proposals to add new API to portable libraries such as Boost to do the necessary conversion, by adding new functions for opening and renaming files. These functions would pass filenames through unchanged on Unix, but translate them to UTF-16 on Windows.[9] This would allow code to be “portable”, but required just as many code changes as calling the wide functions.

With insider build 17035 and the April 2018 update (nominal build 17134) for Windows 10, a “Beta: Use Unicode UTF-8 for worldwide language support” checkbox appeared for setting the locale code page to UTF-8.[a] This allows for calling “narrow” functions, including fopen and SetWindowTextA, with UTF-8 strings. Microsoft claims this option might break some functions (a possible example is _mbsrev[10]) as they were written to assume multibyte encodings used no more than 2 bytes per character, thus until now code pages with more bytes such as GB 18030 (cp54936) and UTF-8 could not be set as the locale.[11]

  1. Jump up^ [WayBack“UTF-8 in Windows”Stack Overflow. Retrieved July 1, 2011.
  2. Jump up^ [WayBack“Boost.Nowide”.
  3. Jump up^ [WayBack
  4. Jump up^ [WayBack“Code Page Identifiers (Windows)”

Via [WayBack] Microsoft Windows Beta UTF-8 support for Ansi API could break things. Wiki Article of the Change… – Tommi Prami – Google+

Related, as handling encoding is hard, especially if it is changed or not your default:


Posted in .NET, C, C++, Delphi, Development, Encoding, GB 18030, Power User, Software Development, UTF-16, UTF-32, UTF-8, UTF16, UTF32, UTF8, Windows, Windows 10 | 2 Comments »

Long read about Unicode: You, Me And The Emoji: Character Sets, Encoding And Emoji – Smashing Magazine

Posted by jpluimers on 2017/11/07

A well worth long rad:

We all recognize emoji. They’ve become the global pop stars of digital communication. But what are they, technically speaking? And what might we learn by taking a closer look at these images, characters, pictographs… whatever they are 🤔 (Thinking Face). We will dig deep to learn about how these thingamajigs work. Please note: Depending on your browser, you may not be able to see all emoji featured in this article (especially the Tifinagh characters). Also, different platforms vary in how they display emoji as well. That’s why the article always provides textual alternatives. Don’t let it discourage you from reading though! Now, let’s start with a seemingly simple question. What are emoji?

[WayBackYou, Me And The Emoji: Character Sets, Encoding And Emoji – Smashing Magazine

Via: [WayBack] Everything you ever wanted to know about characters, encodings, glyphs… and, oh yeah, emoji:, rewarding read. – Ilya Grigorik – Google+

Here is just the ToC:


  1. Character Sets And Document Encoding: An Overview
    1. Characters
    2. Character Sets
    3. Coded Character Sets
    4. Encoding
  2. Declaring Character Sets And Document Encoding On The Web
    1. content-type HTTP Header Declaration
    2. Checking HTTP Headers Using A Browser’s Developer Tools
    3. Checking HTTP Headers Using Web-based Tools
    4. Using A Meta Element With charset Attribute
    5. An Encoding By Any Other Name
  3. What Were We Talking About Again? Oh Yeah, Emoji!
    1. So What Are Emoji?
    2. How Do We Use Emoji?
    3. Character References
    4. Glyphs
    5. How Do We Know If We Have These Symbols?
    6. The Great Emoji Proliferation Of 2016
  4. Emoji OS Support
    1. Emoji Support: Apple Platforms (macOS and iOS)
    2. Emoji Support: Windows
    3. Emoji Support: Linux
    4. Emoji Support: Android
  5. Emoji On The Web
    1. Emoji One
    2. Twemoji
  6. Conclusion


Posted in ASCII, Development, Encoding, ISO-8859, ISO8859, Shift JIS, Unicode, UTF-16, UTF-8, UTF16, UTF8, Windows-1252 | Leave a Comment »

When someone writes UTF-8 and UTF-16 strings to the same file in binary format without converting between them…

Posted by jpluimers on 2017/06/21

A while ago, I had to fix some stuff in an application that would write – using a binary mechanism – UTF-8 and UTF-16 strings (part of it XML in various flavours)  to the same byte stream without converting between the two encodings.

Some links that helped me investigate what was wrong, choose what encoding to use for storage and fix it:


Posted in Delphi, Delphi 10 Seattle, Delphi 10.1 Berlin (BigBen), Delphi XE8, Development, Encoding, Software Development, UTF-16, UTF-8, UTF16, UTF8, XML, XML/XSD | 3 Comments »

Some notes on stripping NULL characters and BOMs from files

Posted by jpluimers on 2017/05/31

A while ago I bumped into applications that write alternating UTF-16 and UTF-8 to files without checking what type of encoding the files were using.

So here are some notes to at least save some of the contents.

TODO: figure out how to strip the BOM.


Posted in Development, Encoding, Software Development, UTF-16, UTF-8, UTF16, UTF8 | Leave a Comment »

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