PAK-files are used in the PC-version. PAK-files is a simple archive format which contains all the other files the game uses.

do
{
    unsigned short offset; // Absolute in file
    unsigned char* filename; // Null terminated C-string
} while ((offset<filesize) && (offset>previousOffset) && (offset>0))
unsigned char *rawData;

The stop-condition in the while loop should cover most of the PAK-files used in most Westwood games, perhaps except the CD-versions of the Kyrandia series