Somre more stuff for parsting

Working on metadata parsing
Runnning into some Reader issues so I might create my own.

squashfs.go

@@ -0,0 +1,87 @@
+package squashfs
+
+import (
+	"encoding/binary"
+	"errors"
+	"io"
+)
+
+var (
+	//ErrNotMagical happens when making a new Squashfs and it doesn't have the magic number
+	ErrNotMagical = errors.New("Not Magical")
+)
+
+//Squashfs is a squashfs backed by a ReadSeeker.
+type Squashfs struct {
+	rdr                *io.SectionReader //underlying reader
+	offset             int
+	super              Superblock
+	flags              SuperblockFlags
+	compressionOptions CompressionOptions
+}
+
+//NewSquashfs creates a new Squashfs backed by the given reader
+func NewSquashfs(reader *io.SectionReader) (*Squashfs, error) {
+	var superblock Superblock
+	err := binary.Read(reader, binary.LittleEndian, &superblock)
+	if err != nil {
+		return nil, err
+	}
+	if superblock.Magic != squashfsMagic {
+		return nil, ErrNotMagical
+	}
+	flags := superblock.GetFlags()
+	var compressionOptions CompressionOptions
+	if flags.CompressorOptions {
+		switch superblock.Compression {
+		case zlibCompression:
+			var gzipOpRaw gzipOptionsRaw
+			err = binary.Read(reader, binary.LittleEndian, &gzipOpRaw)
+			if err != nil {
+				return nil, err
+			}
+			compressionOptions = NewGzipOptions(gzipOpRaw)
+			break
+		default:
+			//TODO: all the compression options
+			return nil, errors.New("This type of compression isn't supported yet")
+		}
+	}
+	//TODO: parse more info
+	return &Squashfs{
+		rdr:                reader,
+		super:              superblock,
+		flags:              flags,
+		compressionOptions: compressionOptions,
+	}, nil
+}
+
+//GetFlags return the SuperblockFlags of the Squashfs
+func (s *Squashfs) GetFlags() SuperblockFlags {
+	return s.super.GetFlags()
+}
+
+//Metadata is a parsed metadata block
+type Metadata struct {
+	Compressed bool
+	Size       uint16
+	Data       *io.SectionReader
+}
+
+func (s *Squashfs) parseNextMetadata() (*Metadata, error) {
+	var metaHeader uint16
+	err := binary.Read(s.rdr, binary.LittleEndian, metaHeader)
+	if err != nil {
+		return nil, err
+	}
+	if metaHeader&0x8000 == 0x8000 {
+		metaHeader = metaHeader &^ 0x8000
+		//TODO: read compressed metadata
+		return nil, errors.New("Metadata is compressed, which is not implemented yet")
+	}
+	return &Metadata{
+		Compressed: false,
+		Size:       metaHeader,
+		//TODO: Data:       io.NewSectionReader(s.rdr, , metaHeader),
+	}, nil
+}