How to extract all files from a subdirectory in an archive?

[gbook]

If I have an archive with paths, such as:

data
data/1
data/1/2

How would I extract all the files stored in data/1/2 into a directory on disk?

[rikyoz]

Hi!
If you're using BitFileExtractor, you can use the extractMatching method, which takes a second parameter with a wildcard filter:

extractor.extractMatching( "path/to/archive.7z", "/data/1/2/*", "out" );

Unfortunately, there's no equivalent method in BitArchiveReader, as I'm still working on "synchronizing" the capabilities of both classes; hopefully I'll add such method in v4.1.

At the moment, with BitArchiveReader you can extract specific items using a vector of indices, so you could write something like this to achieve the same result:

std::vector< std::uint32_t > matchingIndices;
for ( const auto& item : reader ) {
    if ( item.path().rfind( "data/1/2/", 0 ) != 0 ) { // Or C++20's starts_with method.
       matchingIndices.push_back( item.index() );
    }
}
reader.extractTo( "out", matchingIndices );

[gbook]

I tried the BitFileExtractor method

extractor.extractMatching("pathTo.7z", "/data/1/2/*", "C:/temp/data/1/2");

If I use 7zip to open the archive, I see that there are files in that path within the archive, but nothing is extracted to disk when I run that function. Is there a return value for this function, or a way to tell if it successfully matched any files in the archive?