Directorty table info parsing.

Futher work on reading data.

internal/directory/directory.go

@@ -0,0 +1,83 @@
+package directory
+
+import (
+	"encoding/binary"
+	"fmt"
+	"io"
+)
+
+//Header is the header for a directory in the directory table
+type Header struct {
+	Count       uint32
+	InodeOffset uint32
+	InodeNumber uint32
+}
+
+//EntryInit is the values that can be easily decoded
+type EntryInit struct {
+	Offset      uint16
+	InodeOffset int16
+	Type        uint16
+	NameSize    uint16
+}
+
+//Entry is an entry in a directory.
+type Entry struct {
+	Init EntryInit
+	Name []byte
+}
+
+//NewEntry creates a new directory entry
+func NewEntry(rdr io.Reader) (Entry, error) {
+	var entry Entry
+	err := binary.Read(rdr, binary.LittleEndian, entry.Init)
+	if err != nil {
+		return entry, err
+	}
+	entry.Name = make([]byte, entry.Init.NameSize, entry.Init.NameSize)
+	err = binary.Read(rdr, binary.LittleEndian, entry.Name)
+	return entry, err
+}
+
+//Directory is an entry in the directory table of a squashfs.
+//Will only have multiple headers if there are more then 256 entries
+type Directory struct {
+	Headers []Header
+	Entries []Entry
+}
+
+//NewDirectory reads the directory from rdr
+func NewDirectory(rdr io.Reader) (*Directory, error) {
+	var dir Directory
+	var hdr Header
+	err := binary.Read(rdr, binary.LittleEndian, &hdr)
+	if err != nil {
+		return nil, err
+	}
+	headers := hdr.Count / 256
+	if headers%256 > 0 {
+		headers++
+	}
+	headersRead := 1
+	dir.Headers = make([]Header, headers)
+	dir.Headers[0] = hdr
+	for i := uint32(0); i < hdr.Count; i++ {
+		if i != 0 && i%256 == 0 {
+			var newHdr Header
+			err = binary.Read(rdr, binary.LittleEndian, &newHdr)
+			if err != nil {
+				fmt.Println("Error processing header ", headersRead)
+				return &dir, err
+			}
+			dir.Headers[headersRead] = newHdr
+			headersRead++
+		}
+		ent, err := NewEntry(rdr)
+		if err != nil {
+			fmt.Println("Error processing entry ", len(dir.Entries))
+			return &dir, err
+		}
+		dir.Entries = append(dir.Entries, ent)
+	}
+	return &dir, nil
+}