Enhancements to the Blob Classes

This is a short post to describe an update that I made to the Blob classes from the previous article.

Slice!

The first addition is a simple Slice function to the BlobView and BlobSpan classes. This is an alternative way to get a sub-view or sub-span of the data using two indexes (an inclusive begin index and an exclusive end index) rather than an offset and a count. It is most useful when you’re already accessing the data with iterator like indexes.

Typed Array

The next change is adding an ArrayView function to BlobView, a corresponding ArraySpan function to BlobSpan, and both functions to the Blob class. These return a std::span class which represents a typed array over the data. This is a more convenient way to access a contiguous array of items than using pointers and pointer arithmetic explicitly. It also provides iterators to access the data and pass it into other algorithms.

Originally when I implemented these functions there was a dedicated ArrayView class in the codebase, so these functions were intended to return that. However since C++20 the std::span class is available and provides nearly identical functionality, even if it overlaps somewhat with the Blob classes themselves.

Other Changes

The final changes include adding simple unit tests for the new functions and also adding a very simple natvis file.

I know that the unit tests for these classes aren’t exactly the best but they’ve helped me verify the code works as intended.

Source Code

As always these changes are live and available on Github.