...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
The total number of input bytes read so far.
std::size_t total_in = 0;
This field is set by the compression library and must not be updated by the application.
This field can also be used for statistics or progress reports.
After compression, total_in holds the total size of the uncompressed data and may be saved for use by the decompressor (particularly if the decompressor wants to decompress everything in a single step).