Working on how to actually write the archive.

Made SuperblockFlags public so you can set options when writing

bufferedwriter.go

@@ -0,0 +1,15 @@
+package squashfs
+
+import (
+	"io"
+)
+
+type bufferedWriter struct {
+	w      io.Writer
+	buffer []bufferedBytes
+}
+
+type bufferedBytes struct {
+	data   []byte
+	offset int
+}

reader.go

@@ -12,7 +12,7 @@ import (
 )
 
 const (
-	magic = 0x73717368
+	magic uint32 = 0x73717368
 )
 
 var (
@@ -34,7 +34,7 @@ type Reader struct {
 	fragOffsets  []uint64
 	idTable      []uint32
 	super        superblock
-	flags        superblockFlags
+	flags        SuperblockFlags
 }
 
 //NewSquashfsReader returns a new squashfs.Reader from an io.ReaderAt
@@ -53,7 +53,7 @@ func NewSquashfsReader(r io.ReaderAt) (*Reader, error) {
 	// 	return nil, errors.New("BlockSize and BlockLog doesn't match. The archive is probably corrupt")
 	// }
 	rdr.flags = rdr.super.GetFlags()
-	if rdr.flags.CompressorOptions {
+	if rdr.flags.compressorOptions {
 		switch rdr.super.CompressionType {
 		case GzipCompression:
 			var gzip *compression.Gzip

superblock.go

@@ -33,28 +33,38 @@ type superblock struct {
 	ExportTableStart uint64
 }
 
-//SuperblockFlags is the parsed version of Superblock.Flags
+//SuperblockFlags is the series of flags describing how a squashfs archive is packed.
-type superblockFlags struct {
+type SuperblockFlags struct {
-	UncompressedInodes    bool
+	//If true, inodes are stored uncompressed
-	UncompressedData      bool
+	UncompressedInodes bool
-	Check                 bool
+	//If true, data is stored uncompressed
+	UncompressedData bool
+	check            bool
+	//If true, fragments are stored uncompressed
 	UncompressedFragments bool
-	NoFragments           bool
+	//If true, ALL data is stored in sequential data blocks instead of utilizing fragments
-	AlwaysFragments       bool
+	NoFragments bool
-	Duplicates            bool
+	//If true, the last block of data will always be stored as a fragment if it's less then the block size.
-	Exportable            bool
+	AlwaysFragments bool
-	UncompressedXattr     bool
+	//If true, duplicate files are only stored once.
-	NoXattr               bool
+	Duplicates bool
-	CompressorOptions     bool
+	//If true, the export table is populated
-	UncompressedIDs       bool
+	Exportable bool
+	//If true, the xattr table is uncompressed
+	UncompressedXattr bool
+	//If true, the xattr table is not populated
+	NoXattr           bool
+	compressorOptions bool
+	//If true, the UID/GID table is stored uncompressed
+	UncompressedIDs bool
 }
 
 //GetFlags returns a SuperblockFlags for a given superblock.
-func (s *superblock) GetFlags() superblockFlags {
+func (s *superblock) GetFlags() SuperblockFlags {
-	return superblockFlags{
+	return SuperblockFlags{
 		UncompressedInodes:    s.Flags&0x1 == 0x1,
 		UncompressedData:      s.Flags&0x2 == 0x2,
-		Check:                 s.Flags&0x4 == 0x4,
+		check:                 s.Flags&0x4 == 0x4,
 		UncompressedFragments: s.Flags&0x8 == 0x8,
 		NoFragments:           s.Flags&0x10 == 0x10,
 		AlwaysFragments:       s.Flags&0x20 == 0x20,
@@ -62,7 +72,49 @@ func (s *superblock) GetFlags() superblockFlags {
 		Exportable:            s.Flags&0x80 == 0x80,
 		UncompressedXattr:     s.Flags&0x100 == 0x100,
 		NoXattr:               s.Flags&0x200 == 0x200,
-		CompressorOptions:     s.Flags&0x400 == 0x400,
+		compressorOptions:     s.Flags&0x400 == 0x400,
 		UncompressedIDs:       s.Flags&0x800 == 0x800,
 	}
 }
+
+//ToUint returns the uint16 representation of the given SuperblockFlags
+func (s *SuperblockFlags) ToUint() uint16 {
+	var out uint16
+	if s.UncompressedInodes {
+		out = out | 0x1
+	}
+	if s.UncompressedData {
+		out = out | 0x2
+	}
+	if s.check {
+		out = out | 0x4
+	}
+	if s.UncompressedFragments {
+		out = out | 0x8
+	}
+	if s.NoFragments {
+		out = out | 0x10
+	}
+	if s.AlwaysFragments {
+		out = out | 0x20
+	}
+	if s.Duplicates {
+		out = out | 0x40
+	}
+	if s.Exportable {
+		out = out | 0x80
+	}
+	if s.UncompressedXattr {
+		out = out | 0x100
+	}
+	if s.NoXattr {
+		out = out | 0x200
+	}
+	if s.compressorOptions {
+		out = out | 0x400
+	}
+	if s.UncompressedIDs {
+		out = out | 0x800
+	}
+	return out
+}

writer.go

@@ -13,18 +13,6 @@ import (
 	"github.com/CalebQ42/squashfs/internal/compression"
 )
 
-type fileHolder struct {
-	reader      io.Reader
-	path        string
-	name        string
-	symLocation string
-	UID         int
-	GUID        int
-	perm        int
-	folder      bool
-	symlink     bool
-}
-
 //Writer is used to creaste squashfs archives. Currently unusable
 //TODO: Make usable
 type Writer struct {
@@ -33,8 +21,10 @@ type Writer struct {
 	symlinkTable    map[string]string //[oldpath]newpath
 	uidGUIDTable    []int
 	compressionType int
-	Flags           superblockFlags
+	//Flags are the SuperblockFlags used when writing the archive.
-	allowErrors     bool
+	//Currently Duplicates, Exportable, UncompressedXattr, NoXattr values are ignored
+	Flags       SuperblockFlags
+	allowErrors bool
 }
 
 //NewWriter creates a new with the default options (Gzip compression and allow errors)
@@ -62,6 +52,19 @@ func NewWriterWithOptions(compressionType int, allowErrors bool) (*Writer, error
 	}, nil
 }
 
+//fileHolder holds the necessary information about a given file inside of a squashfs
+type fileHolder struct {
+	reader      io.Reader
+	path        string
+	name        string
+	symLocation string
+	UID         int
+	GUID        int
+	perm        int
+	folder      bool
+	symlink     bool
+}
+
 //AddFile attempts to add an os.File to the archive at it's root.
 func (w *Writer) AddFile(file *os.File) error {
 	return w.AddFileToFolder("/", file)
@@ -318,9 +321,3 @@ func (w *Writer) WriteToFilename(filepath string) error {
 	_, err = w.WriteTo(newFil)
 	return err
 }
-
-//WriteTo attempts to write the archive to the given io.Writer.
-func (w *Writer) WriteTo(write io.Writer) (int64, error) {
-	//TODO
-	return 0, errors.New("I SAID DON'T")
-}

writer_write.go

@@ -0,0 +1,12 @@
+package squashfs
+
+import (
+	"errors"
+	"io"
+)
+
+//WriteTo attempts to write the archive to the given io.Writer.
+func (w *Writer) WriteTo(write io.Writer) (int64, error) {
+	//TODO
+	return 0, errors.New("I SAID DON'T")
+}