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I converted my program from Delphi 4 to Delphi 2009 a year ago, mainly to make the jump to Unicode, but also to gain the benefits of all those years of Delphi improvements.
My code, of course, is therefore all legacy code. It uses short strings that have now conveniently all become long Unicode strings, and I've changed all the old ANSI functions to the new equivalent.
But with Delphi 2009, they introduced the TStringBuilder class, presumably modelled after the StringBuilder class of .NET.
My program does a lot of string handling and manipulation, and can load hundreds of megabytes of large strings into memory at once to work with.
I don't know a lot about Delphi's implementation of TStringBuilder, but I heard that some of its operations are faster than using the default string operations.
My question is whether or not it is worthwhile for me to go through the effort and convert my standard strings to use the TStringBuilder class. What would I gain and lose from doing that?
Thank you for your answers and leading me to my conclusion, which is not to bother unless .NET compatibility is required.
On his blog on Delphi 2009 String Performance, Jolyon Smith states:
But it looks to me as if TStringBuilder is there primarily as a .NET compatibility fixture, rather than to provide any real benefit to developers of Win32 applications, with the possible exception of developers wishing or needing to single-source a Win32/.NET codebase where string handling performance isn’t a concern.
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If you are using two or three string concatenations, use a string. StringBuilder will improve performance in cases where you make repeated modifications to a string or concatenate many strings together. In short, use StringBuilder only for a large number of concatenations.
StringBuilder classes should be used when you have to make a lot of modifications to strings of characters.As we know String objects are immutable, so if you choose to do a lot of manipulations with String objects, you will end up with a lot of abandoned String objects in the String pool.
Fortunately, you don't need to use StringBuilder anymore - the compiler can handle it for you. String concatenation has always been a well-discussed topic among Java developers. It's been costly. Let's first dig into the issue of why it's costly.
StringBuilder in Java is a class used to create a mutable, or in other words, a modifiable succession of characters. Like StringBuffer, the StringBuilder class is an alternative to the Java Strings Class, as the Strings class provides an immutable succession of characters.
To the best of my knowledge TStringBuilder was introduced just for some parity with .NET and Java, it seems to be more of a tick the box type feature than any major advance.
Consensus seems to be that TStringBuilder is faster in some operations but slower in others.
Your program sounds like an interesting one to do a before/after TStringBuilder comparison with but I wouldn't do it other than as an academic exercise.
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