Author Archives: Vladimir Panteleev

About Vladimir Panteleev

Please see my homepage for my other projects.

Functional image processing in D

I’ve recently completed an overhaul of the graphics package of my D library. The goals for the overhaul were inspired by D’s std.algorithm and std.range modules:

  • Present everything as small, composable components
  • Avoid implicit copying and prefer lazy evaluation
  • Use templates for efficient code

From its first iteration, all components of the image processing package were templated by the color type. This is not a conventional way to implement graphics libraries – most libraries abstract away the exact color type the image uses behind an OOP interface, or they simply convert all images to a single in-memory pixel format. However, for most cases, this is wasteful and inefficient – usually, the programmer already knows the exact format that an image will be in, with notable exceptions being applications in which the image data comes from user input (e.g. image editors). Instead, this library declares all image types as templates, with the type indicating the image’s color being a template parameter.

I’m rather pleased with the result of this overhaul, so I’d like to share some highlights in this article. Continue reading

Low-overhead components

My personal dream of an ideal programming language is one that allows defining flexible, configurable components that can be coupled together with very little overhead, producing in the end code that, if reverse-engineered, would appear to be hand-written and optimized for the specific task at hand. Preconfigured component configurations / presets would be available for common use, favoring safety and feature-completeness, but for performance-critical cases, the programmer could break them down and strip out unneeded features to reduce overhead, or customize by injecting their own components into the mix. Continue reading

Installing PHP and Apache module under /home

Let’s say you have your own Apache 2 setup in your home directory, and you want to build and install PHP as well, and set it up as an Apache module without root privileges (e.g. if you want to use a different PHP version than the one installed globally).

You may run into problems such as PHP’s configure script not detecting apxs2 (and thus not building an Apache module). Continue reading

Very Sleepy fork

I got fed up with waiting/pestering Richard Mitton (aka Kayamon / @grumpygiant) to integrate the Very Sleepy patches I’ve sent him last year or putting the code on a software forge, so I’m publishing my patches on GitHub myself.

Very Sleepy is a polling Windows profiler with a wxWidgets-based GUI. This is a fork of the latest released version at the time of writing (0.82).

There have been a few more forks of Very Sleepy (e.g. here and here), but these are based off older versions. It’s possible that their changes had already been merged into the official version.

Update: I’ve continued development of my fork, at the above-mentioned location. Check the GitHub project for the changelog, downloads, and more information.

DHCP test client

While trying to set up my home network, I was dismayed that there was no simple way to test the DHCP server. Snooping packets is limited to examining existing traffic.

DHCP test tools exist (DHCPing and dhquery), however both are outdated and don’t work with the latest versions of their requirements, and both won’t work on Windows.

I’ve written a simple DHCP “client” which can receive and decode broadcasted DHCP replies, as well as send out DHCP “discover” packets.

Source, download.

64-bit CacheSet

SysInternals CacheSet has a limitation: it is unable to set a cache size larger than 4GB. This is due to the fact that it is a 32-bit application, and the respective API (NtSetSystemInformation) accepts new settings as a 32-bit byte count.

The solution: use the 64-bit API, which uses 64-bit integers. I’ve written a very simple 64-bit CacheSet-alike – just enter the desired cache size (in bytes). You can use the original CacheSet to check the new settings (just don’t hit “Apply”, or your settings might get clobbered).

Source, download.