Convert more bespoke methods to io.Reader/io.Writer interfaces

[rbdr/mobius] / hotline / flattened_file_object.go

diff --git a/hotline/flattened_file_object.go b/hotline/flattened_file_object.go
index c57de19fea4063a91e5f5b9a8e1a27cf009550f7..dfa86e091a06fc2fc73f6973b3362e0678ad9439 100644 (file)
--- a/hotline/flattened_file_object.go
+++ b/hotline/flattened_file_object.go
@@ -1,8 +1,10 @@
 package hotline
 
 import (
+       "bytes"
        "encoding/binary"
        "io"
+       "slices"
 )
 
 type flattenedFileObject struct {
@@ -101,7 +103,8 @@ func (ffif *FlatFileInformationFork) Size() [4]byte {
 
 func (ffo *flattenedFileObject) TransferSize(offset int64) []byte {
        // get length of the flattenedFileObject, including the info fork
-       payloadSize := len(ffo.BinaryMarshal())
+       b, _ := io.ReadAll(ffo)
+       payloadSize := len(b)
 
        // length of data fork
        dataSize := binary.BigEndian.Uint32(ffo.FlatFileDataForkHeader.DataSize[:])
@@ -129,23 +132,57 @@ type FlatFileForkHeader struct {
        DataSize        [4]byte
 }
 
-func (ffif *FlatFileInformationFork) MarshalBinary() []byte {
-       var b []byte
-       b = append(b, ffif.Platform...)
-       b = append(b, ffif.TypeSignature...)
-       b = append(b, ffif.CreatorSignature...)
-       b = append(b, ffif.Flags...)
-       b = append(b, ffif.PlatformFlags...)
-       b = append(b, ffif.RSVD...)
-       b = append(b, ffif.CreateDate...)
-       b = append(b, ffif.ModifyDate...)
-       b = append(b, ffif.NameScript...)
-       b = append(b, ffif.ReadNameSize()...)
-       b = append(b, ffif.Name...)
-       b = append(b, ffif.CommentSize...)
-       b = append(b, ffif.Comment...)
+func (ffif *FlatFileInformationFork) Read(p []byte) (int, error) {
+       return copy(p,
+               slices.Concat(
+                       ffif.Platform,
+                       ffif.TypeSignature,
+                       ffif.CreatorSignature,
+                       ffif.Flags,
+                       ffif.PlatformFlags,
+                       ffif.RSVD,
+                       ffif.CreateDate,
+                       ffif.ModifyDate,
+                       ffif.NameScript,
+                       ffif.ReadNameSize(),
+                       ffif.Name,
+                       ffif.CommentSize,
+                       ffif.Comment,
+               ),
+       ), io.EOF
+}
+
+// Write implements the io.Writeer interface for FlatFileInformationFork
+func (ffif *FlatFileInformationFork) Write(p []byte) (int, error) {
+       nameSize := p[70:72]
+       bs := binary.BigEndian.Uint16(nameSize)
+       total := 72 + bs
+
+       ffif.Platform = p[0:4]
+       ffif.TypeSignature = p[4:8]
+       ffif.CreatorSignature = p[8:12]
+       ffif.Flags = p[12:16]
+       ffif.PlatformFlags = p[16:20]
+       ffif.RSVD = p[20:52]
+       ffif.CreateDate = p[52:60]
+       ffif.ModifyDate = p[60:68]
+       ffif.NameScript = p[68:70]
+       ffif.NameSize = p[70:72]
+       ffif.Name = p[72:total]
+
+       if len(p) > int(total) {
+               ffif.CommentSize = p[total : total+2]
+               commentLen := binary.BigEndian.Uint16(ffif.CommentSize)
+
+               commentStartPos := int(total) + 2
+               commentEndPos := int(total) + 2 + int(commentLen)
+
+               ffif.Comment = p[commentStartPos:commentEndPos]
 
-       return b
+               total = uint16(commentEndPos)
+       }
+
+       return int(total), nil
 }
 
 func (ffif *FlatFileInformationFork) UnmarshalBinary(b []byte) error {
@@ -178,42 +215,40 @@ func (ffif *FlatFileInformationFork) UnmarshalBinary(b []byte) error {
        return nil
 }
 
-func (ffo *flattenedFileObject) BinaryMarshal() []byte {
-       var out []byte
-       out = append(out, ffo.FlatFileHeader.Format[:]...)
-       out = append(out, ffo.FlatFileHeader.Version[:]...)
-       out = append(out, ffo.FlatFileHeader.RSVD[:]...)
-       out = append(out, ffo.FlatFileHeader.ForkCount[:]...)
-
-       out = append(out, []byte("INFO")...)
-       out = append(out, []byte{0, 0, 0, 0}...)
-       out = append(out, make([]byte, 4)...)
-       out = append(out, ffo.FlatFileInformationFork.DataSize()...)
-
-       out = append(out, ffo.FlatFileInformationFork.Platform...)
-       out = append(out, ffo.FlatFileInformationFork.TypeSignature...)
-       out = append(out, ffo.FlatFileInformationFork.CreatorSignature...)
-       out = append(out, ffo.FlatFileInformationFork.Flags...)
-       out = append(out, ffo.FlatFileInformationFork.PlatformFlags...)
-       out = append(out, ffo.FlatFileInformationFork.RSVD...)
-       out = append(out, ffo.FlatFileInformationFork.CreateDate...)
-       out = append(out, ffo.FlatFileInformationFork.ModifyDate...)
-       out = append(out, ffo.FlatFileInformationFork.NameScript...)
-       out = append(out, ffo.FlatFileInformationFork.ReadNameSize()...)
-       out = append(out, ffo.FlatFileInformationFork.Name...)
-       out = append(out, ffo.FlatFileInformationFork.CommentSize...)
-       out = append(out, ffo.FlatFileInformationFork.Comment...)
-
-       out = append(out, ffo.FlatFileDataForkHeader.ForkType[:]...)
-       out = append(out, ffo.FlatFileDataForkHeader.CompressionType[:]...)
-       out = append(out, ffo.FlatFileDataForkHeader.RSVD[:]...)
-       out = append(out, ffo.FlatFileDataForkHeader.DataSize[:]...)
-
-       return out
+// Read implements the io.Reader interface for flattenedFileObject
+func (ffo *flattenedFileObject) Read(p []byte) (int, error) {
+       return copy(p, slices.Concat(
+               ffo.FlatFileHeader.Format[:],
+               ffo.FlatFileHeader.Version[:],
+               ffo.FlatFileHeader.RSVD[:],
+               ffo.FlatFileHeader.ForkCount[:],
+               []byte("INFO"),
+               []byte{0, 0, 0, 0},
+               make([]byte, 4),
+               ffo.FlatFileInformationFork.DataSize(),
+               ffo.FlatFileInformationFork.Platform,
+               ffo.FlatFileInformationFork.TypeSignature,
+               ffo.FlatFileInformationFork.CreatorSignature,
+               ffo.FlatFileInformationFork.Flags,
+               ffo.FlatFileInformationFork.PlatformFlags,
+               ffo.FlatFileInformationFork.RSVD,
+               ffo.FlatFileInformationFork.CreateDate,
+               ffo.FlatFileInformationFork.ModifyDate,
+               ffo.FlatFileInformationFork.NameScript,
+               ffo.FlatFileInformationFork.ReadNameSize(),
+               ffo.FlatFileInformationFork.Name,
+               ffo.FlatFileInformationFork.CommentSize,
+               ffo.FlatFileInformationFork.Comment,
+               ffo.FlatFileDataForkHeader.ForkType[:],
+               ffo.FlatFileDataForkHeader.CompressionType[:],
+               ffo.FlatFileDataForkHeader.RSVD[:],
+               ffo.FlatFileDataForkHeader.DataSize[:],
+       ),
+       ), io.EOF
 }
 
-func (ffo *flattenedFileObject) ReadFrom(r io.Reader) (int, error) {
-       var n int
+func (ffo *flattenedFileObject) ReadFrom(r io.Reader) (int64, error) {
+       var n int64
 
        if err := binary.Read(r, binary.BigEndian, &ffo.FlatFileHeader); err != nil {
                return n, err
@@ -229,7 +264,8 @@ func (ffo *flattenedFileObject) ReadFrom(r io.Reader) (int, error) {
                return n, err
        }
 
-       if err := ffo.FlatFileInformationFork.UnmarshalBinary(ffifBuf); err != nil {
+       _, err := io.Copy(&ffo.FlatFileInformationFork, bytes.NewReader(ffifBuf))
+       if err != nil {
                return n, err
        }