#1483 7-Zip can't detect all archives stored in 1 file

[quanta]

If an archive includes more than 1 archive header, such as AwardBIOS 4.5-6.00PG firmware, both command line and GUI versions of 7-Zip only find the first archive and ignore the rest. If the master archive in question contains extra data before the first archive supported by 7-Zip, such as later AwardBIOS 6.00PG firmware that can only be opened by MODBIN6, 7-Zip simply cannot find it. 7-Zip should not stop detection processing as soon as it finds 1 archive. Instead, it should scan the remaining of the file to identify more contents that can be extracted by 7-Zip. If necessary, backtrack the file pointer and use another scanning filter to identify more files or more correctly to identify files.

This same bug also affects the detection of InstallShield 2/3 SFX ZIP archives (see bug '7-Zip can't extract files in InstallShield 2/3 SFX ZIP archives') and possibly Windows Installer archives (see bug 'MSI/CAB unpacker does not extract all objects'). Fully solving this bug may also solve the problem of handling self-extracting LHA archives.