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+meta:
+  id: squashfs
+  title: SquashFS
+  file-extension:
+    - squashfs
+    - snap
+    - sqfs
+  endian: le
+  bit-endian: be
+  license: CC0-1.0
+  xref:
+    wikidata: Q389314
+doc: |
+  SquashFS is a compressed filesystem in a file, that can be read-only
+  accessed from low memory devices. It is popular for booting LiveCDs and
+  packing self-contained binaries. SquashFS format is used by Ubuntu .snap
+  packages. SquashFS is natively supported by Linux Kernel.
+doc-ref: https://github.com/AgentD/squashfs-tools-ng/blob/master/doc/format.txt
+seq:
+  - id: superblock
+    type: superblock
+enums:
+  compressor:
+    1: zlib
+    2: lzma
+    3: lzo
+    4: xz
+    5: lz4
+    6: zstd
+  inode_type:
+    1: basic_directory
+    2: basic_file
+    3: basic_symlink
+    4: basic_block_device
+    5: basic_character_device
+    6: basic_named_pipe
+    7: basic_socket
+    8: extended_directory
+    9: extended_file
+    10: extended_symlink
+    11: extended_block_device
+    12: extended_character_device
+    13: extended_named_pipe
+    14: extended_socket
+instances:
+  id_table:
+    io: _root._io
+    pos: superblock.id_table_start
+    # ceil(id_count/2048)
+    type: "metablock_reference_list(((superblock.id_count%2048 >0) ? 1 : 0) + superblock.id_count/2048)"
+  xattr_id_table:
+    if: superblock.xattr_id_table_start != 0xffff_ffff_ffff_ffff
+    io: _root._io
+    pos: superblock.xattr_id_table_start
+    type: metablock_list
+  inode_table:
+    io: _root._io
+    pos: superblock.inode_table_start
+    type: inode_table
+    size: (superblock.directory_table_start-superblock.inode_table_start)
+  directory_table:
+    io: _root._io
+    pos: superblock.directory_table_start
+    type: directory_table
+    size: (superblock.fragment_table_start-superblock.directory_table_start)
+  fragment_table:
+    io: _root._io
+    pos: superblock.fragment_table_start
+    # ceil(frag_count*8/16384)
+    type: "metablock_reference_list(((superblock.frag_count%512 >0) ? 1 : 0) + superblock.frag_count/512)"
+  export_table:
+    io: _root._io
+    pos: superblock.export_table_start
+    # ceil(inode_count*8/8192)
+    type: "metablock_reference_list(((superblock.inode_count%1024 >0) ? 1 : 0) + superblock.inode_count/1024)"
+  fragments:
+    io: _root.fragment_table.data._io
+    type: fragments
+  uid_gid_entries:
+    io: _root.id_table.data._io
+    type: uid_gid_entries
+types:
+  flags:
+    seq:
+      # bit count starts from the largest, byte count form the smallest
+      - id: nfs_export_table            # 0x0080
+        type: b1
+      - id: data_deduplicated           # 0x0040
+        type: b1
+      - id: fragments_always_generated  # 0x0020
+        type: b1
+      - id: fragments_not_used          # 0x0010
+        type: b1
+      - id: fragments_uncompresed       # 0x0008
+        type: b1
+      - type: b1                        # 0x0004 bit is unused
+      - id: data_blocks_uncompresed     # 0x0002
+        type: b1
+      - id: inodes_uncompresed          # 0x0001
+        type: b1
+      # bits 0x0100 are below, starting from the largest
+      - type: b4                        # bits 11110000 are unused
+      - id: id_table_uncompresed        # 0x0800
+        type: b1
+      - id: compressor_options_present  # 0x0400
+        type: b1
+      - id: xattrs_absent               # 0x0200
+        type: b1
+      - id: xattrs_uncompressed         # 0x0100
+        type: b1
+  superblock:
+    seq:
+      - id: magic
+        contents: 'hsqs'
+      - id: inode_count
+        type: u4
+      - id: mod_time
+        type: u4
+        doc: Unix times of last modification.
+      - id: block_size
+        type: u4
+        doc: |
+          The size of a data block in bytes. Must be a power of two between
+          4096 (4k) and 1048576 (1 MiB).
+      - id: frag_count
+        type: u4
+        doc: The number of entries in the fragment table.
+      - id: compressor
+        type: u2
+        enum: compressor
+        doc: Compressor used for both data and meta data blocks.
+      - id: block_log
+        type: u2
+        doc: |
+          The log2 of the block size. If the two fields do not agree, the
+          archive is considered corrupted.
+      - id: flags
+        type: flags
+      - id: id_count
+        type: u2
+        doc: The number of entries in the ID lookup table.
+      - id: version_major
+        type: u2
+        valid:
+          eq: 4
+      - id: version_minor
+        type: u2
+        valid:
+          eq: 0
+      - id: root_inode_ref
+        type: inode_reference
+        doc: A reference to the inode of the root directory.
+      - id: bytes_used
+        type: u8
+        doc: |
+          The number of bytes used by the archive. Because SquashFS
+          archives must be padded to a multiple of the underlying device
+          block size, this can be less than the actual file size.
+      - id: id_table_start
+        type: u8
+      - id: xattr_id_table_start
+        type: u8
+      - id: inode_table_start
+        type: u8
+      - id: directory_table_start
+        type: u8
+      - id: fragment_table_start
+        type: u8
+      - id: export_table_start
+        type: u8
+  inode_reference:
+    instances:
+      inode_block_start:
+        value: (raw >> 16) & 0xFFFFFFFF
+      block_offset:
+        value: raw & 0xFFFF
+      inode_table:
+        io: _root._io
+        pos: _root.superblock.inode_table_start + inode_block_start
+        type: inode_table_entry(block_offset)
+        size: (_root.superblock.directory_table_start-_root.superblock.inode_table_start-inode_block_start)
+    seq:
+      - id: raw
+        type: u8
+  inode_table_entry:
+    params:
+      - id: offset
+        type: u2
+    instances:
+      inode_header:
+        io: inodes._io
+        pos: offset
+        type: inode_header
+    seq:
+      - id: metablock_list
+        type: metablock_list
+      - id: inodes
+        # we want to concatenate the data of all metablocks, so we fake a 0-sized entry here. the decode method will be called with an empty array, but the constructor has the needed netablocks
+        size: 0
+        process: concat(metablock_list)
+        type: block_content
+  inode_table:
+    seq:
+      - id: metablock_list
+        type: metablock_list
+      - id: inodes
+        # we want to concatenate the data of all metablocks, so we fake a 0-sized entry here. the decode method will be called with an empty array, but the constructor has the needed netablocks
+        size: 0
+        process: concat(metablock_list)
+        type: inode_headers
+  directory_table:
+    seq:
+      - id: metablock_list
+        type: metablock_list
+      - id: directory
+        # we want to concatenate the data of all metablocks, so we fake a 0-sized entry here. the decode method will be called with an empty array, but the constructor has the needed netablocks
+        size: 0
+        process: concat(metablock_list)
+        type: block_content
+  metablock_list:
+    seq:
+      - id: metablock
+        type: metablock
+        repeat: eos
+  metablock_reference_list:
+    params:
+      - id: num_metablock_reference
+        type: u8
+    seq:
+      - id: metablock_reference
+        type: metablock_reference(_index)
+        repeat: expr
+        repeat-expr: num_metablock_reference
+      - id: data
+        # we want to concatenate the data of all metablocks, so we fake a 0-sized entry here. the decode method will be called with an empty array, but the constructor has the needed netablocks
+        size: 0
+        process: concat(metablock_reference)
+        type: block_content
+  metablock_reference:
+    params:
+      - id: index
+        type: u4
+    instances:
+      metablock:
+        io: _root._io
+        pos: position
+        type: metablock
+    seq:
+      - id: position
+        type: u8
+  metablock:
+    instances:
+      compression:
+        value: (compression_and_len&0x8000)==0
+      len_data:
+        value: compression_and_len&0x7FFF
+    seq:
+      - id: compression_and_len
+        type: u2
+      - id: data
+        size: len_data
+        type: uncompressed_data(compression, 8192, false)
+  uncompressed_data:
+    params:
+      - id: compression
+        type: b1
+      - id: max_size
+        type: u4
+      - id: padded
+        type: b1
+    seq:
+      - id: data
+        size-eos: true
+        process: decompress(compression, _root.superblock.compressor, max_size, padded)
+  block_content:
+    seq:
+      - id: dummy
+        size: 0
+  directory:
+    seq:
+      - id: directory_header
+        type: directory_header
+        repeat: eos
+  directory_header:
+    seq:
+      - id: count
+        type: u4
+      - id: start
+        type: u4
+      - id: inode_number
+        type: s4
+      - id: directory_entry
+        type: directory_entry
+        # sanity check
+        if: count < 256
+        repeat: expr
+        repeat-expr: count + 1
+  directory_entry:
+    seq:
+      - id: offset
+        type: u2
+      - id: inode_offset
+        type: s2
+      - id: type
+        type: u2
+      - id: name_size
+        type: u2
+      - id: name
+        type: str
+        size: name_size + 1
+        encoding: 'ASCII'
+  inode_headers:
+    seq:
+      - id: inode_header
+        type: inode_header
+        repeat: expr
+        repeat-expr: _root.superblock.inode_count
+  inode_header:
+    seq:
+      - id: type
+        type: u2
+        enum: inode_type
+      - id: permissions
+        type: u2
+      - id: uid
+        type: u2
+      - id: gid
+        type: u2
+      - id: mtime
+        type: u4
+      - id: inode_number
+        type: u4
+      - id: header
+        type:
+          switch-on: type
+          cases:
+            'inode_type::basic_directory': inode_header_basic_directory
+            'inode_type::extended_directory': inode_header_extended_directory
+            'inode_type::basic_file': inode_header_basic_file
+            'inode_type::extended_file': inode_header_extended_file
+  inode_header_basic_directory:
+    instances:
+      directory_table:
+        io: _root._io
+        pos: _root.superblock.directory_table_start + dir_block_start
+        type: directory_table
+        size: (_root.superblock.fragment_table_start - _root.superblock.directory_table_start - dir_block_start)
+      dir:
+        io: directory_table.directory._io
+        pos: block_offset
+        size: file_size - 3
+        type: directory
+    seq:
+      - id: dir_block_start
+        type: u4
+      - id: hard_link_count
+        type: u4
+      - id: file_size
+        type: u2
+      - id: block_offset
+        type: u2
+      - id: parent_inode_number
+        type: u4
+  inode_header_extended_directory:
+    instances:
+      directory_table:
+        io: _root._io
+        pos: _root.superblock.directory_table_start + dir_block_start
+        type: directory_table
+        size: (_root.superblock.fragment_table_start - _root.superblock.directory_table_start - dir_block_start)
+      dir:
+        io: directory_table.directory._io
+        pos: block_offset
+        size: file_size - 3
+        type: directory
+    seq:
+      - id: hard_link_count
+        type: u4
+      - id: file_size
+        type: u4
+      - id: dir_block_start
+        type: u4
+      - id: parent_inode_number
+        type: u4
+      - id: num_index
+        type: u2
+      - id: block_offset
+        type: u2
+      - id: xattr_idx
+        type: u4
+      - id: index
+        type: directory_index
+        repeat: expr
+        repeat-expr: num_index
+  directory_index:
+    seq:
+      - id: index
+        type: u4
+      - id: start
+        type: u4
+      - id: name_size
+        type: u4
+      - id: name
+        type: str
+        size: name_size + 1
+        encoding: 'ASCII'
+  inode_header_basic_file:
+    instances:
+      fragment:
+        value: _root.fragments.fragments[frag_index]
+        if: frag_index!=0xFFFFFFFF
+    seq:
+      - id: blocks_start
+        type: u4
+      - id: frag_index
+        type: u4
+      - id: block_offset
+        type: u4
+      - id: file_size
+        type: u4
+      - id: block_sizes
+        type: u4
+        repeat: expr
+        doc: |
+          A list of block sizes. If this file ends in a fragment, the size of this list is the number of full data
+          blocks needed to store file_size bytes. If this file does not have a fragment, the size of the list is the 
+          number of blocks needed to store file_size bytes, rounded up.
+        repeat-expr: "file_size / _root.superblock.block_size + (frag_index==0xFFFFFFFF and (file_size.as<f4> / _root.superblock.block_size.as<f4>) > file_size / _root.superblock.block_size ? 1 : 0)"
+      - id: blocks
+        size: 0
+        type: data_block(_index==0?blocks_start:blocks[_index-1].start+blocks[_index-1].len_data, block_sizes[_index], _index!=block_sizes.size-1)
+        repeat: expr
+        repeat-expr: block_sizes.size
+  inode_header_extended_file:
+    instances:
+      fragment:
+        value: _root.fragments.fragments[frag_index]
+        if: frag_index!=0xFFFFFFFF
+    seq:
+      - id: blocks_start
+        type: u8
+      - id: file_size
+        type: u8
+      - id: sparse
+        type: u8
+      - id: hardlink_count
+        type: u4
+      - id: frag_index
+        type: u4
+      - id: block_offset
+        type: u4
+      - id: xattr_idx
+        type: u4
+      - id: block_sizes
+        type: u4
+        repeat: expr
+        doc: |
+          A list of block sizes. If this file ends in a fragment, the size of this list is the number of full data
+          blocks needed to store file_size bytes. If this file does not have a fragment, the size of the list is the 
+          number of blocks needed to store file_size bytes, rounded up.
+        repeat-expr: "file_size / _root.superblock.block_size + (frag_index==0xFFFFFFFF and (file_size.as<f4> / _root.superblock.block_size.as<f4>) > file_size / _root.superblock.block_size ? 1 : 0)"
+      - id: blocks
+        size: 0
+        type: data_block(_index==0?blocks_start:blocks[_index-1].start+blocks[_index-1].len_data, block_sizes[_index], _index!=block_sizes.size-1)
+        repeat: expr
+        repeat-expr: block_sizes.size
+  data_block:
+    params:
+      - id: start
+        type: u4
+      - id: compression_and_len
+        type: u4
+      - id: padded
+        type: b1
+    instances:
+      compression:
+        value: (compression_and_len&0x1000000)==0
+      len_data:
+        value: compression_and_len&0xFFFFFF
+      data:
+        io: _root._io
+        pos: start
+        size: len_data
+        type: uncompressed_data(compression, _root.superblock.block_size, padded)
+  fragments:
+    seq:
+      - id: fragments
+        type: fragment
+        repeat: expr
+        repeat-expr: _root.superblock.frag_count
+  fragment:
+    seq:
+      - id: start
+        type: u8
+      - id: compression_and_len
+        type: u4
+      - id: unused
+        type: u4
+      - id: block
+        size: 0
+        type: data_block(start, compression_and_len, false)
+  uid_gid_entries:
+    seq:
+      - id: uid_gid_entries
+        type: uid_gid_entry
+        repeat: expr
+        repeat-expr: _root.superblock.id_count
+  uid_gid_entry:
+    seq:
+      - id: uid_gid
+        type: u4