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

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Archive for the ‘Windows Development’ Category

Optimizing BitBlt by generating code on the fly – The Old New Thing

Posted by jpluimers on 2020/03/25

Blast from the past machine generated code by the various assembly versions of the  [WayBack] Windows BitBlt function [WayBackOptimizing BitBlt by generating code on the fly – The Old New Thing.

Via: [WayBack] Rodrigo Ruz on Twitter: “Optimizing BitBlt by generating code on the fly https://t.co/gWmKjex20i”

–jeroen

Posted in Development, History, Software Development, The Old New Thing, Windows Development | Leave a Comment »

User Experience topics like “Why does Explorer use the term KB instead of KiB”

Posted by jpluimers on 2020/03/24

Designing for a good user experience is hard, especially to programmers. So if you are a programmer, please read, let them sink in, rinse, repeat the below linked articles multiple times. Being ~15 years old, they are still so very relevant:

–jeroen

Posted in Development, Software Development, The Old New Thing, Usability, User Experience (ux), Windows Development | Leave a Comment »

What are the size restrictions for the VCL controls like TPanel and TPaintBox…

Posted by jpluimers on 2020/02/27

Via [WayBack] What are the size restrictions for the VCL controls like TPanel and TPaintBox.? Are they documented anywhere? I’m talking about placing these on a TScro… – Thomas Mueller (dummzeuch) – Google+:

Some Windows messages use the LPARAM to carry width and height, which allows only 16 bit for each.

So 32k-1 (or decimal 32767) is the maximum size of a GDI based visual element in Windows.

–jeroen

Posted in Development, Software Development, Windows Development | Leave a Comment »

Why does HRESULT begin with H when it’s not a handle to anything? – The Old New Thing

Posted by jpluimers on 2020/02/06

Interesting bit of history: [WayBackWhy does HRESULT begin with H when it’s not a handle to anything? – The Old New Thing.

TL;DR:

  1. It used to be a handle
  2. Few programs cared about the underlying objects
  3. Managing the underlying objects was way too expensive
  4. It got trimmed down to a number, but the name stuck

–jeroen

Posted in Development, History, Software Development, The Old New Thing, Windows Development | 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:

Python:

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

Delphi:

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:

–jeroen

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 »

 
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