Starting on writing the library

Currently just parses the superblock (but that works!)

unsquash.go

@@ -1,9 +1,30 @@
 package squashfs
 
-import "io"
+import (
+	"encoding/binary"
+	"io"
+)
 
-//Squashfs is a squashfs backed by a reader.
+//Squashfs is a squashfs backed by a ReadSeeker.
 type Squashfs struct {
-	rdr   *io.Reader //underlyting reader
+	rdr   *io.ReaderAt //underlying reader
 	super Superblock
 }
+
+//NewSquashfs creates a new Squashfs backed by the given reader
+func NewSquashfs(reader io.ReaderAt) (*Squashfs, error) {
+	var superblock Superblock
+	err := binary.Read(io.NewSectionReader(reader, 0, int64(binary.Size(superblock))), binary.LittleEndian, &superblock)
+	if err != nil {
+		return nil, err
+	}
+	return &Squashfs{
+		rdr:   &reader,
+		super: superblock,
+	}, nil
+}
+
+//GetFlags return the SuperblockFlags of the Squashfs
+func (s *Squashfs) GetFlags() SuperblockFlags {
+	return s.super.GetFlags()
+}