Xref stream progress

sign/pdftrailer.go

@@ -6,39 +6,42 @@ import (
 )
 
 func (context *SignContext) writeTrailer() error {
-	trailer_length := context.PDFReader.XrefInformation.IncludingTrailerEndPos - context.PDFReader.XrefInformation.EndPos
 
-	// Read the trailer so we can replace the size.
+	if context.PDFReader.XrefInformation.Type == "table" {
-	context.InputFile.Seek(context.PDFReader.XrefInformation.EndPos+1, 0)
+		trailer_length := context.PDFReader.XrefInformation.IncludingTrailerEndPos - context.PDFReader.XrefInformation.EndPos
-	trailer_buf := make([]byte, trailer_length)
-	if _, err := context.InputFile.Read(trailer_buf); err != nil {
-		return err
-	}
 
-	root_string := "Root " + context.CatalogData.RootString
+		// Read the trailer so we can replace the size.
-	new_root := "Root " + strconv.FormatInt(int64(context.CatalogData.ObjectId), 10) + " 0 R"
+		context.InputFile.Seek(context.PDFReader.XrefInformation.EndPos+1, 0)
+		trailer_buf := make([]byte, trailer_length)
+		if _, err := context.InputFile.Read(trailer_buf); err != nil {
+			return err
+		}
 
-	size_string := "Size " + strconv.FormatInt(context.PDFReader.XrefInformation.ItemCount, 10)
+		root_string := "Root " + context.CatalogData.RootString
-	new_size := "Size " + strconv.FormatInt(context.PDFReader.XrefInformation.ItemCount+4, 10)
+		new_root := "Root " + strconv.FormatInt(int64(context.CatalogData.ObjectId), 10) + " 0 R"
 
-	info := context.PDFReader.Trailer().Key("Info")
+		size_string := "Size " + strconv.FormatInt(context.PDFReader.XrefInformation.ItemCount, 10)
-	infoPtr := info.GetPtr()
+		new_size := "Size " + strconv.FormatInt(context.PDFReader.XrefInformation.ItemCount+4, 10)
 
-	info_string := "Info " + strconv.Itoa(int(infoPtr.GetID())) + " " + strconv.Itoa(int(infoPtr.GetGen())) + " R"
+		info := context.PDFReader.Trailer().Key("Info")
-	new_info := "Info " + strconv.FormatInt(int64(context.InfoData.ObjectId), 10) + " 0 R"
+		infoPtr := info.GetPtr()
 
-	trailer_string := string(trailer_buf)
+		info_string := "Info " + strconv.Itoa(int(infoPtr.GetID())) + " " + strconv.Itoa(int(infoPtr.GetGen())) + " R"
-	trailer_string = strings.Replace(trailer_string, root_string, new_root, -1)
+		new_info := "Info " + strconv.FormatInt(int64(context.InfoData.ObjectId), 10) + " 0 R"
-	trailer_string = strings.Replace(trailer_string, size_string, new_size, -1)
-	trailer_string = strings.Replace(trailer_string, info_string, new_info, -1)
 
-	// Write the new trailer.
+		trailer_string := string(trailer_buf)
-	if _, err := context.OutputFile.Write([]byte(trailer_string)); err != nil {
+		trailer_string = strings.Replace(trailer_string, root_string, new_root, -1)
-		return err
+		trailer_string = strings.Replace(trailer_string, size_string, new_size, -1)
+		trailer_string = strings.Replace(trailer_string, info_string, new_info, -1)
+
+		// Write the new trailer.
+		if _, err := context.OutputFile.Write([]byte(trailer_string)); err != nil {
+			return err
+		}
 	}
 
 	// Write the new xref start position.
-	if _, err := context.OutputFile.Write([]byte(strconv.FormatInt(context.NewXrefStart, 10) + "\n")); err != nil {
+	if _, err := context.OutputFile.Write([]byte("\nstartxref\n" + strconv.FormatInt(context.NewXrefStart, 10) + "\n")); err != nil {
 		return err
 	}
 

sign/pdfxref.go

@@ -3,16 +3,21 @@ package sign
 import (
 	"errors"
 	"strconv"
+	"encoding/hex"
+	"compress/zlib"
+	"bytes"
 )
 
 func (context *SignContext) writeXref() error {
 
-	// @todo: support stream xref.
-
 	if context.PDFReader.XrefInformation.Type == "table" {
 		if err := context.writeXrefTable(); err != nil {
 			return err
 		}
+	} else if context.PDFReader.XrefInformation.Type == "stream" {
+		if err := context.writeXrefStream(); err != nil {
+			return err
+		}
 	} else {
 		return errors.New("Unkwn xref type: " + context.PDFReader.XrefInformation.Type)
 	}
@@ -71,3 +76,76 @@ func (context *SignContext) writeXrefTable() error {
 
 	return nil
 }
+
+func (context *SignContext) writeXrefStream() error {
+	// @todo: DO NOT FORGET TO ADD SELF REFERENCE!!!
+	// @todo: fix format (columns) for stream
+	// @todo: add PNG-Up support.
+	var streamBytes bytes.Buffer
+	w := zlib.NewWriter(&streamBytes)
+
+	// Create the new catalog xref line.
+	visual_signature_object_start_position := strconv.FormatInt(context.Filesize, 10)
+	visual_signature_xref_line := leftPad(visual_signature_object_start_position, "0", 10-len(visual_signature_object_start_position)) + " 00000 n \n"
+
+	// Write the new catalog xref line.
+	if _, err := w.Write([]byte(visual_signature_xref_line)); err != nil {
+		return err
+	}
+
+	// Create the new catalog xref line.
+	catalog_object_start_position := strconv.FormatInt(context.Filesize+context.VisualSignData.Length, 10)
+	catalog_xref_line := leftPad(catalog_object_start_position, "0", 10-len(catalog_object_start_position)) + " 00000 n \n"
+
+	// Write the new catalog xref line.
+	if _, err := w.Write([]byte(catalog_xref_line)); err != nil {
+		return err
+	}
+
+	// Create the new signature xref line.
+	info_object_start_position := strconv.FormatInt(context.Filesize+context.VisualSignData.Length+context.CatalogData.Length, 10)
+	info_xref_line := leftPad(info_object_start_position, "0", 10-len(info_object_start_position)) + " 00000 n \n"
+
+	// Write the new signature xref line.
+	if _, err := w.Write([]byte(info_xref_line)); err != nil {
+		return err
+	}
+
+	// Create the new signature xref line.
+	signature_object_start_position := strconv.FormatInt(context.Filesize+context.VisualSignData.Length+context.CatalogData.Length+context.InfoData.Length, 10)
+	signature_xref_line := leftPad(signature_object_start_position, "0", 10-len(signature_object_start_position)) + " 00000 n \n"
+
+	// Write the new signature xref line.
+	if _, err := w.Write([]byte(signature_xref_line)); err != nil {
+		return err
+	}
+	w.Close()
+
+	new_info := "Info " + strconv.FormatInt(int64(context.InfoData.ObjectId), 10) + " 0 R"
+	new_root := "Root " + strconv.FormatInt(int64(context.CatalogData.ObjectId), 10) + " 0 R"
+
+	id := context.PDFReader.Trailer().Key("ID")
+
+	id0 := hex.EncodeToString([]byte(id.Index(0).RawString()))
+	id1 := hex.EncodeToString([]byte(id.Index(0).RawString()))
+
+	new_xref := strconv.Itoa(int(context.SignData.ObjectId + 1)) + " 0 obj\n"
+	new_xref += "<< /Type /XRef /Length " + strconv.Itoa(len(streamBytes.Bytes()))  + " /Filter /FlateDecode /DecodeParms << /Columns 5 /Predictor 12 >> /W [ 1 3 1 ] /Prev " +  strconv.FormatInt(context.PDFReader.XrefInformation.StartPos, 10) + " /Size " + strconv.FormatInt(context.PDFReader.XrefInformation.ItemCount+5, 10) + " /Index [ 5 " + strconv.FormatInt(context.PDFReader.XrefInformation.ItemCount, 10) + " ] /" + new_info + " /" + new_root + " /ID [<" + id0 + "><" + id1 + ">] >>\n"
+	if _, err := context.OutputFile.Write([]byte(new_xref)); err != nil {
+		return err
+	}
+
+	if _, err := context.OutputFile.Write([]byte("stream\n")); err != nil {
+		return err
+	}
+
+	if _, err := context.OutputFile.Write(streamBytes.Bytes()); err != nil {
+		return err
+	}
+
+	if _, err := context.OutputFile.Write([]byte("\nendstream\n")); err != nil {
+		return err
+	}
+
+	return nil
+}