Support parsing and getting the actual version number and changing the output PDF version

pdf/core/parser.go

@@ -21,7 +21,7 @@ import (
 )
 
 // Regular Expressions for parsing and identifying object signatures.
-var rePdfVersion = regexp.MustCompile(`%PDF-(\d\.\d)`)
+var rePdfVersion = regexp.MustCompile(`%PDF-(\d)\.(\d)`)
 var reEOF = regexp.MustCompile("%%EOF")
 var reXrefTable = regexp.MustCompile(`\s*xref\s*`)
 var reStartXref = regexp.MustCompile(`startx?ref\s*(\d+)`)
@@ -33,6 +33,9 @@ var reXrefSubsection = regexp.MustCompile(`(\d+)\s+(\d+)\s*$`)
 var reXrefEntry = regexp.MustCompile(`(\d+)\s+(\d+)\s+([nf])\s*$`)
 
 type PdfParser struct {
+	majorVersion int
+	minorVersion int
+
 	rs               io.ReadSeeker
 	reader           *bufio.Reader
 	xrefs            XrefTable
@@ -631,27 +634,34 @@ func (this *PdfParser) ParseDict() (*PdfObjectDictionary, error) {
 }
 
 // Parse the pdf version from the beginning of the file.
-func (this *PdfParser) parsePdfVersion() (float64, error) {
+// Returns the major and minor parts of the version.
+// E.g. for "PDF-1.7" would return 1 and 7.
+func (this *PdfParser) parsePdfVersion() (int, int, error) {
 	this.rs.Seek(0, os.SEEK_SET)
 	var offset int64 = 20
 	b := make([]byte, offset)
 	this.rs.Read(b)
 
 	result1 := rePdfVersion.FindStringSubmatch(string(b))
-	if len(result1) < 2 {
+	if len(result1) < 3 {
 		common.Log.Debug("Error: PDF Version not found!")
-		return -1, errors.New("PDF version not found")
+		return 0, 0, errors.New("PDF version not found")
 	}
 
-	version, err := strconv.ParseFloat(result1[1], 64)
+	majorVersion, err := strconv.ParseInt(result1[1], 10, 64)
 	if err != nil {
-		return 0, err
+		return 0, 0, err
+	}
+
+	minorVersion, err := strconv.ParseInt(result1[2], 10, 64)
+	if err != nil {
+		return 0, 0, err
 	}
 
 	//version, _ := strconv.Atoi(result1[1])
-	common.Log.Debug("Pdf version %f", version)
+	common.Log.Debug("Pdf version %d.%d", majorVersion, minorVersion)
 
-	return version, nil
+	return int(majorVersion), int(minorVersion), nil
 }
 
 // Conventional xref table starting with 'xref'.
@@ -1321,10 +1331,13 @@ func NewParser(rs io.ReadSeeker) (*PdfParser, error) {
 
 	// printXrefTable(parser.xrefs)
 
-	_, err = parser.parsePdfVersion()
+	majorVersion, minorVersion, err := parser.parsePdfVersion()
 	if err != nil {
-		return nil, fmt.Errorf("Unable to parse version (%s)", err)
+		common.Log.Error("Unable to parse version: %v", err)
+		return nil, err
 	}
+	parser.majorVersion = majorVersion
+	parser.minorVersion = minorVersion
 
 	parser.trailer = trailer
 

pdf/model/writer.go

@@ -70,6 +70,10 @@ type PdfWriter struct {
 	encryptObj  *PdfIndirectObject
 	ids         *PdfObjectArray
 
+	// PDF version
+	majorVersion int
+	minorVersion int
+
 	// Objects to be followed up on prior to writing.
 	// These are objects that are added and reference objects that are not included
 	// for writing.
@@ -88,6 +92,11 @@ func NewPdfWriter() PdfWriter {
 	w.objects = []PdfObject{}
 	w.pendingObjects = map[PdfObject]*PdfObjectDictionary{}
 
+	// PDF Version.  Can be changed if using more advanced features in PDF.
+	// By default it is set to 1.3.
+	w.majorVersion = 1
+	w.minorVersion = 3
+
 	// Creation info.
 	infoDict := PdfObjectDictionary{}
 	infoDict[PdfObjectName("Producer")] = MakeString(getPdfProducer())
@@ -101,7 +110,6 @@ func NewPdfWriter() PdfWriter {
 	catalog := PdfIndirectObject{}
 	catalogDict := PdfObjectDictionary{}
 	catalogDict[PdfObjectName("Type")] = MakeName("Catalog")
-	catalogDict[PdfObjectName("Version")] = MakeName("1.3")
 	catalog.PdfObject = &catalogDict
 
 	w.root = &catalog
@@ -127,6 +135,12 @@ func NewPdfWriter() PdfWriter {
 	return w
 }
 
+// Set the PDF version of the output file.
+func (this *PdfWriter) SetVersion(majorVersion, minorVersion int) {
+	this.majorVersion = majorVersion
+	this.minorVersion = minorVersion
+}
+
 // Set the optional content properties.
 func (this *PdfWriter) SetOCProperties(ocProperties PdfObject) error {
 	dict := this.catalog
@@ -638,11 +652,13 @@ func (this *PdfWriter) Write(ws io.WriteSeeker) error {
 			}
 		}
 	}
+	// Set version in the catalog.
+	(*this.catalog)["Version"] = MakeName(fmt.Sprintf("%d.%d", this.majorVersion, this.minorVersion))
 
 	w := bufio.NewWriter(ws)
 	this.writer = w
 
-	w.WriteString("%PDF-1.3\n")
+	w.WriteString(fmt.Sprintf("%%PDF-%d.%d\n", this.majorVersion, this.minorVersion))
 	w.WriteString("%âãÏÓ\n")
 	w.Flush()