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For professors' note: use PVS-Studio to get students familiar with code analysis tools

Reading time4 min
Views1.7K

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Our support chats and some other indirect signs showed that there are many students among our free users. Here's the reason: PVS-Studio is now more often used by professors in courses related to software development. We are very pleased with this, and we decided to write this small article to fall under notice of other teachers. We are pleased that students become acquainted with the methodology of static code analysis in general and the PVS-Studio tool in particular. Our team will try to contribute to this trend.
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Tips and tricks from my Telegram-channel @pythonetc, August 2019

Reading time4 min
Views1.7K


It is a new selection of tips and tricks about Python and programming from my Telegram-channel @pythonetc.

Previous publications


If an instance of a class doesn’t have an attribute with the given name, it tries to access the class attribute with the same name.

>>> class A:
...     x = 2
...
>>> A.x
2
>>> A().x
2
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Using PVS-Studio Static Analyzer in C and C++ Development for Embedded Systems

Reading time4 min
Views1.4K

This article will tell you how to launch analysis of an embedded project and how to work with the analyzer's report. The PVS-Studio analyzer supports a number of compilers for embedded systems. The current version allows checking projects built with one of the following compilers under Window, Linux, and macOS:

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Exceptional situations: part 1 of 4

Reading time11 min
Views2.2K


Introduction


It’s time to talk about exceptions or, rather, exceptional situations. Before we start, let’s look at the definition. What is an exceptional situation?


This is a situation that makes the execution of current or subsequent code incorrect. I mean different from how it was designed or intended. Such a situation compromises the integrity of an application or its part, e.g. an object. It brings the application into an extraordinary or exceptional state.


But why do we need to define this terminology? Because it will keep us in some boundaries. If we don’t follow the terminology, we can get too far from a designed concept which may result in many ambiguous situations. Let’s see some practical examples:


 struct Number
 {
     public static Number Parse(string source)
     {
         // ...
         if(!parsed)
         {
             throw new ParsingException();
         }
         // ...
     }

     public static bool TryParse(string source, out Number result)
     {
        // ..
        return parsed;
     }
 }

This example seems a little strange, and it is for a reason. I made this code slightly artificial to show the importance of problems appearing in it. First, let’s look at the Parse method. Why should it throw an exception?

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In-App Updates Flexible Flow: Speed Up the App Update Process on Android

Reading time7 min
Views6.4K


With a variety of new tools and features announced at Android Dev Summit, special attention should be given to the In-App Updates (IAUs) API allowing developers to increase the speed of delivering features, bug-fixes and performance improvements to active users. Since this feature was finally released after Google I/O 2019, in this article I’ll deep dive on IAUs API, describe in details recommended user flows and provide with some code samples. Moreover, I'll share some experience of IAUs integration in the Pandao app, a marketplace platform for Chinese goods.
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Cataclysm Dark Days Ahead: Static Analysis and Roguelike Games

Reading time10 min
Views4.7K
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You must have already guessed from the title that today's article will be focusing on bugs in software source code. But not only that. If you are not only interested in C++ and in reading about bugs in other developers' code but also dig unusual video games and wonder what «roguelikes» are and how you play them, then welcome to read on!
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PVS-Studio for Java hits the road. Next stop is Elasticsearch

Reading time11 min
Views2.2K

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The PVS-Studio team has been keeping the blog about the checks of open-source projects by the same-name static code analyzer for many years. To date, more than 300 projects have been checked, the base of errors contains more than 12000 cases. Initially the analyzer was implemented for checking C and C++ code, support of C# was added later. Therefore, from all checked projects the majority (> 80%) accounts for C and C++. Quite recently Java was added to the list of supported languages, which means that there is now a whole new open world for PVS-Studio, so it's time to complement the base with errors from Java projects.

The Java world is vast and varied, so one doesn't even know where to look first when choosing a project to test the new analyzer. Ultimately, the choice fell on the full-text search and analytical engine Elasticsearch. It is quite a successful project, and it's even especially pleasant to find errors in significant projects. So, what defects did PVS-Studio for Java manage to detect? Further talk will be right about the results of the check.
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Making a DIY thermal camera based on a Raspberry Pi

Reading time6 min
Views62K
image

Hi everyone!

Winter has arrived, and so I had to check the thermal insulation of my out of town residence dacha. And it just turned out a famous Chinese marketplace started to sell cheap thermal camera modules. So I decided to DIY it up and build a rather exotic and useful thing — a heat visor for the home. Why not? Especially since I had a Raspberry Pi lying around anyway… The result is down below.
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My Pascal compiler and Polish contemporary art

Reading time5 min
Views7.4K

Origins


Several years ago I wrote a Pascal compiler. The motivation was simple: as a teenager, I had learnt from my first programming textbooks that a compiler is a very sophisticated thing. This claim eventually became a challenge and required to be tested by experience.

image
ha.art.pl

First, a simplistic PL/0 compiler came into being, and later an almost fully-functional Pascal compiler for MS-DOS has grown from it. My source of inspiration was the Compiler Construction book by Niklaus Wirth, the inventor of the Pascal language. I don't care if Wirth's views are now considered obsolete and have no direct connections to the IT mainstream, or if the compiler design fashion has changed. It is enough to know that his techniques are still simple, elegant, and — last but not least — bring much fun, since it is more appealing to parse a program source with a handwritten recursive descent parser and generate the machine code, rather than to call yaccs, bisons and all their descendants.

My compiler's fate was not so trivial. It has lived two lives: the first one in my own hands, and the second in the hands of computer antiquarians from Poland.

Real-time edge detection using FPGA

Reading time8 min
Views16K

Introduction


Our project implements a real-time edge detection system based on capturing image frames from an OV7670 camera and streaming them to a VGA monitor after applying a grayscale filter and Sobel operator. Our design is built on a Cyclone IV FPGA board which enables us to optimize the performance using the powerful features of the low-level hardware and parallel computations which is important to meet the requirements of the real-time system.


We used ZEOWAA FPGA development board which is based on Cyclone IV (EP4CE6E22C8N). Also, we used Quartus Prime Lite Edition as a development environment and Verilog HDL as a programming language. In addition, we used the built-in VGA interface to drive the VGA monitor, and GPIO (General Pins for Input and Output) to connect the external hardware with our board.


ZEOWAA FPGA development board

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How linear algebra is applied in machine learning

Reading time5 min
Views14K

When you study an abstract subject like linear algebra, you may wonder: why do you need all these vectors and matrices? How are you going to apply all this inversions, transpositions, eigenvector and eigenvalues for practical purposes?


Well, if you study linear algebra with the purpose of doing machine learning, this is the answer for you.


In brief, you can use linear algebra for machine learning on 3 different levels:


  • application of a model to data;
  • training the model;
  • understanding how it works or why it does not work.

drawing
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«Чемодан из крокодиловой кожи» или «мешок с аллигатором»: сравнение подключенных к Lokalise онлайн-переводчиков

Reading time9 min
Views3.9K
Пользователи Lokalise могут выбирать, локализовать им свой продукт с привлечением наёмных переводчиков площадки, с собственной командой или исключительно своими силами. Именно для упрощения процедуры локализации тех проектов, где профессиональные переводчики не нужны и достаточно собственных знаний языка, мы и предоставляем нашим пользователям возможность использовать встроенные в Lokalise популярные системы машинного перевода от Google, Yandex, Microsoft и SDL. О том, как переводят эти системы, мы сегодня и поговорим на конкретных примерах.



Google Machine Translate/Google Neural Translate


Около полугода назад компания Google заявила о подключении очередного набора языков к нейронной сети своего сервиса Google Translate, в том числе и русского. Событие это стало знаковым для всего русскоязычного интернет-пространства: ежедневно тысячи человек пользуются встроенным в Chrome переводчиком Google или идут на сайт Google Translate за переводом иностранного текста на родной язык.
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Analysis of commits and pull requests in Travis CI, Buddy and AppVeyor using PVS-Studio

Reading time10 min
Views815

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Starting from the version 7.04, the PVS-Studio analyzer for C and C++ languages on Linux and macOS provides the test feature of checking the list of specified files. Using the new mode, you can configure the analyzer to check commits and pull requests. This article covers setting up the check of certain modified files from a GitHub project in such popular CI (Continuous Integration) systems, as Travis CI, Buddy and AppVeyor.
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PVS-Studio in the Clouds: CircleCI

Reading time11 min
Views755

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This is a new piece of our series of articles about using the PVS-Studio static analyzer with cloud CI systems. Today we are going to look at another service, CircleCI. We'll take the Kodi media player application as a test project and see if we can find any interesting bugs in its source code.
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Dark theme of Thunderbird as a reason to run a code analyzer

Reading time12 min
Views2.1K
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The adventures with the Mozilla Thunderbird mail client began with automatic update to version 68.0. More text in pop-up notifications and default dark theme are the notable features of this version. Occasionally I found an error that I immediately craved to detect with static analysis. This became the reason to go for another check of the project source code using PVS-Studio. It so happened that by the time of the analysis, the bug had already been fixed. However, since we've paid some attention to the project, there's no reason not to write about other found defects.

Introduction


The dark theme of the new Thunderbird version looks pretty. I like dark themes. I've already switched to them in messengers, Windows, macOS. Soon iPhone will be updated to iOS 13 with a dark theme. For this reason I even had to change my iPhone 5S for a newer model. In practice, it turned out that a dark theme requires more effort for developers to pick up the colors of the interface. Not everyone can handle it the first time.
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Make it easier to get finished: Interview with John Romero, developer of Doom

Reading time12 min
Views6.2K
At the last Tech Train IT festival, we met the legendary John Romero, who designed and developed the iconic Wolfenstein 3D, Doom, and Quake. We talked about whether game developers need soft skills, which working tools to pay attention to, and which co-founder of Id Software's favorite toys are. Questions were asked by Nikita Tsaplin, the founder of RUVDS.


→ Text and video in Russian

WinForms: Errors, Holmes

Reading time17 min
Views1.1K

Picture 5

We like to search for errors in Microsoft projects. Why? It's simple: their projects are usually easy to check (you can work in Visual Studio environment for which PVS-Studio has a convenient plugin) and they contain few errors. That's why the usual work algorithm is as follows: find and download an open source project from MS; check it; choose interesting errors; make sure there are few of them; write an article without forgetting to praise the developers. Great! Win-win-win: it took a little time, the bosses are glad to see new materials in the blog, and karma is fine. But this time «something went wrong». Let's see what we have found in the source code of Windows Forms and whether we should speak highly of Microsoft this time.
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