dmg.hexpat

#pragma description Apple Disk Image Trailer (DMG)

#pragma endian big

import type.magic;
import type.size;
import type.guid;
import std.mem;

// Parse DMG Structure per http://newosxbook.com/DMG.html
//
// UDIFResourceFile starts at size(file) - 512
struct UDIFResourceFile {
    type::Magic<"koly"> Signature;      // Magic ('koly')
    u32 Version;                        // Current version is 4
    type::Size<u32> HeaderSize;         // sizeof(this), always 512
    u32 Flags;
    u64 RunningDataForkOffset;          //
    u64 DataForkOffset;                 // Data fork offset (usually 0, beginning of file)
    type::Size<u64> DataForkLength;     // Size of data fork (usually up to the XMLOffset, below)
    u64 RsrcForkOffset;                 // Resource fork offset, if any
    type::Size<u64> RsrcForkLength;     // Resource fork length, if any
    u32 SegmentNumber;                  // Usually 1, may be 0
    u32 SegmentCount;                   // Usually 1, may be 0

    type::GUID SegmentID;               // 128-bit GUID identifier of segment (if SegmentNumber !=0)

    u32 DataChecksumType;               // Data fork
    type::Size<u32> DataChecksumSize;   // Checksum Information
    u32 DataChecksum[32];               // Up to 128-bytes (32 x 4) of checksum

    u64 XMLOffset;                      // Offset of property list in DMG, from beginning
    type::Size<u64> XMLLength;          // Length of property list
    u8  Reserved1[120];                 // 120 reserved bytes - zeroed

    u32 ChecksumType;                   // Master
    type::Size<u32> ChecksumSize;       // Checksum information
    u32 Checksum[32];                   // Up to 128-bytes (32 x 4) of checksum

    u32 ImageVariant;                   // Commonly 1
    u64 SectorCount;                    // Size of DMG when expanded, in sectors

    u32 reserved2;                      // 0
    u32 reserved3;                      // 0
    u32 reserved4;                      // 0
};


UDIFResourceFile trailer @ std::mem::size() - 512;

char metadata_plist[trailer.XMLLength] @ trailer.XMLOffset;