// Archive Header (0x10 bytes)
struct XanaduHeader {
    char headerTag[4];          // "PDA\0" - Constant header tag
    uint32 compressionType;     // Constant value of 2
    uint32 fileEntryOffset;     // Offset to end of compressed file data
    uint32 fileCount;           // Number of files in archive
};

// Raw File Data Section (Variable Length)
// Each file consists of a 0x10 header followed by compressed data
struct FileData {
    uint32 uncompressedSize;    // Expected size after decompression
    uint32 compressedSize;      // Size of compressed data after this header
    uchar unknown[8];           // Unknown purpose, sometimes 0
    uchar compressedData[compressedSize - 16];  // Raw deflate compressed data
};

// File Entry Section (Variable Length)  
// Located at header.fileEntryOffset, repeated fileCount times
struct FileEntry {
    time_t archiveTime;         // C time format - when file was packed/modified
    uint32 unknown;             // Unknown purpose
    uint32 compressedSize;      // Size including 0x10 header
    uint32 uncompressedSize;    // Size after decompression
    uint16 fileNameLength;      // Length including junk padding
    uint16 fileFlags;           // Unknown flags
    uint32 fileOffset;          // Offset to raw data section
    char fileName[fileNameLength];  // Filename + 1-3 bytes random padding
                                    // Padded to make total length divisible by 4
};

XanaduHeader header;
FileData fileData[header.fileCount];
FileEntry fileEntry[header.fileCount];