Move changes from exp2 to main

This is largely a move to simplify a lot of the readers Also further breaks out functions.
2022-05-10 01:12:13 -05:00
parent 0a2ced9072
commit 16ef5838c3
41 changed files with 1377 additions and 2293 deletions
@@ -6,82 +6,73 @@ import (
 	"io"
 )

-//Header is the header for a directory in the directory table
-type Header struct {
-	Count       uint32
-	InodeOffset uint32
-	InodeNumber uint32
+type header struct {
+	Entries    uint32
+	InodeStart uint32
+	Num        uint32
 }

-//EntryRaw is the values that can be easily decoded
-type EntryRaw struct {
-	Offset      uint16
-	InodeOffset int16
-	Type        uint16
-	NameSize    uint16
+type entryInit struct {
+	Offset    uint16
+	NumOffset int16
+	Type      uint16
+	NameSize  uint16
+}
+
+type entry struct {
+	entryInit
+	Name []byte
 }

-//Entry is an entry in a directory.
 type Entry struct {
-	Name             string
-	InodeOffset      uint32
-	InodeBlockOffset uint16
-	Type             uint16
+	Name       string
+	BlockStart uint32
+	Type       uint16
+	Offset     uint16
 }

-//NewEntry creates a new directory entry
-func NewEntry(rdr io.Reader) (*Entry, error) {
-	var raw EntryRaw
-	err := binary.Read(rdr, binary.LittleEndian, &raw)
+func readEntry(r io.Reader) (e entry, err error) {
+	err = binary.Read(r, binary.LittleEndian, &e.entryInit)
 	if err != nil {
-		return nil, err
-	}
-	tmp := make([]byte, raw.NameSize+1)
-	err = binary.Read(rdr, binary.LittleEndian, &tmp)
-	if err != nil {
-		return nil, err
-	}
-	return &Entry{
-		InodeBlockOffset: raw.Offset,
-		Type:             raw.Type,
-		Name:             string(tmp),
-	}, nil
-}
-
-//NewDirectory reads the directory from rdr
-func NewDirectory(base io.Reader, size uint32) (entries []*Entry, err error) {
-	tmp := make([]byte, size)
-	base.Read(tmp)
-	rdr := bytes.NewBuffer(tmp)
-	for {
-		var hdr Header
-		err = binary.Read(rdr, binary.LittleEndian, &hdr)
-		if err == io.ErrUnexpectedEOF {
-			err = nil
-			break
-		} else if err != nil {
-			return nil, err
-		}
-		hdr.Count++
-		headers := hdr.Count / 256
-		if hdr.Count%256 > 0 {
-			headers++
-		}
-		for i := uint32(0); i < hdr.Count; i++ {
-			if i != 0 && i%256 == 0 {
-				err = binary.Read(rdr, binary.LittleEndian, &hdr)
-				if err != nil {
-					return nil, err
-				}
-			}
-			var ent *Entry
-			ent, err = NewEntry(rdr)
-			if err != nil {
-				return nil, err
-			}
-			ent.InodeOffset = hdr.InodeOffset
-			entries = append(entries, ent)
-		}
+		return
 	}
+	e.Name = make([]byte, e.NameSize+1)
+	err = binary.Read(r, binary.LittleEndian, &e.Name)
 	return
 }
+
+func ReadEntries(rdr io.Reader, size uint32) (e []Entry, err error) {
+	dat := make([]byte, size)
+	rdr.Read(dat)
+	r := bytes.NewReader(dat)
+	var h header
+	var en entry
+	for {
+		err = binary.Read(r, binary.LittleEndian, &h)
+		if err == io.ErrUnexpectedEOF {
+			err = nil
+			return
+		} else if err != nil {
+			return
+		}
+		h.Entries++
+		for i := 0; i < int(h.Entries); i++ {
+			if i != 0 && i%256 == 0 {
+				err = binary.Read(r, binary.LittleEndian, &h)
+				if err != nil {
+					return
+				}
+			}
+			en, err = readEntry(r)
+			if err != nil {
+				return
+			}
+			e = append(e, Entry{
+				Name:       string(en.Name),
+				BlockStart: h.InodeStart,
+				Type:       en.Type,
+				Offset:     en.Offset,
+			})
+		}
+	}
+}