Book Image

Delphi High Performance

By : Primož Gabrijelčič
Book Image

Delphi High Performance

By: Primož Gabrijelčič

Overview of this book

Delphi is a cross-platform Integrated Development Environment (IDE) that supports rapid application development for Microsoft Windows, Apple Mac OS X, Google Android, iOS, and now Linux with RAD Studio 10.2. This book will be your guide to build efficient high performance applications with Delphi. The book begins by explaining how to find performance bottlenecks and apply the correct algorithm to fix them. It will teach you how to improve your algorithms before taking you through parallel programming. You’ll then explore various tools to build highly concurrent applications. After that, you’ll delve into improving the performance of your code and master cross-platform RTL improvements. Finally, we’ll go through memory management with Delphi and you’ll see how to leverage several external libraries to write better performing programs. By the end of the book, you’ll have the knowledge to create high performance applications with Delphi.
Table of Contents (16 chapters)
Title Page
Copyright and Credits
Packt Upsell

Speeding up SlowCode

For the last practical example, we can try speeding up Mr. Smith's SlowCode from Chapter 1, About Performance. Here, we immediately ran into a problem. To fix or change an algorithm we must understand what the code does. This happens a lot in practice, especially when you inherit some code. Reading and understanding code that you didn't write is an important skill.

Let's try to understand the first part of SlowCode. The for loop in SlowMethod starts counting with 2. Then it calls ElementInDataDivides, which does nothing as the data list is empty. Next, SlowMethod adds 2 to the list.

Next, i takes the value of 3. ElementInDataDivides checks if 3 is divisible by 2. It is not, so SlowMethod adds 3 to the list.

In the next step, i = 4, it is divisible by 2, and 4 is not added to the list. 5 is then added to the list (it is not divisible by 2 or 3), 6 is not (divisible by 2), 7 is added (not divisible by 2, 3, or 5), 8 is not (divisible by 2), 9 is not (divisible by 3), and...