Introduce helper functions to set default catalog sort flag and creation date value. Remove regular expression scheme that effectively ignored the embedded creation date when comparing PDFs.

3 files changed, 42 insertions, 18 deletions

diff --git a/compare.go b/compare.go
index 6a79cba..3fd7eaf 100644
--- a/compare.go
+++ b/compare.go
@@ -21,15 +21,6 @@ import (
 	"fmt"
 	"io"
 	"io/ioutil"
-	"regexp"
-)
-
-var (
-	// 00000230  44 46 20 31 2e 37 29 0a  2f 43 72 65 61 74 69 6f  |DF 1.7)./Creatio|
-	// 00000240  6e 44 61 74 65 20 28 44  3a 32 30 31 35 31 30 30  |nDate (D:2015100|
-	// 00000250  38 31 32 33 30 34 35 29  0a 3e 3e 0a 65 6e 64 6f  |8123045).>>.endo|
-	creationDateRe = regexp.MustCompile("/CreationDate \\(D:\\d{14}\\)")
-	fixDate        = []byte("/CreationDate (D:20000101000000)")
 )
 
 func writeBytes(leadStr string, startPos int, sl []byte) {
@@ -71,15 +62,11 @@ func checkBytes(pos int, sl1, sl2 []byte) (eq bool) {
 }
 
 // compareBytes compares the bytes referred to by sl1 with those referred to by
-// sl2. The comparison is done byte-for-byte with the exception of the
-// CreationDate fields which are effectively ignored. Nil is returned if the
-// buffers are equal, otherwise an error.
+// sl2. Nil is returned if the buffers are equal, otherwise an error.
 func compareBytes(sl1, sl2 []byte) (err error) {
 	var posStart, posEnd, len1, len2, length int
 	var diffs bool
 
-	sl1 = creationDateRe.ReplaceAll(sl1, fixDate)
-	sl2 = creationDateRe.ReplaceAll(sl2, fixDate)
 	len1 = len(sl1)
 	len2 = len(sl2)
 	length = len1
diff --git a/fpdf.go b/fpdf.go
index d501574..aeb0c3e 100644
--- a/fpdf.go
+++ b/fpdf.go
@@ -42,6 +42,11 @@ import (
 	"time"
 )
 
+var gl struct {
+	catalogSort  bool
+	creationDate time.Time
+}
+
 type fmtBuffer struct {
 	bytes.Buffer
 }
@@ -180,6 +185,8 @@ func fpdfNew(orientationStr, unitStr, sizeStr, fontDirStr string, size SizeType)
 	// Set default PDF version number
 	f.pdfVersion = "1.3"
 	f.layerInit()
+	f.catalogSort = gl.catalogSort
+	f.creationDate = gl.creationDate
 	return
 }
 
@@ -2987,6 +2994,13 @@ func (f *Fpdf) outf(fmtStr string, args ...interface{}) {
 	f.out(sprintf(fmtStr, args...))
 }
 
+// SetDefaultCatalogSort sets the default value of the catalog sort flag that
+// will be used when initializing a new Fpdf instance. See SetCatalogSort() for
+// more details.
+func SetDefaultCatalogSort(flag bool) {
+	gl.catalogSort = flag
+}
+
 // SetCatalogSort sets a flag that will be used, if true, to consistently order
 // the document's internal resource catalogs. This method is typically only
 // used for test purposes.
@@ -2994,10 +3008,17 @@ func (f *Fpdf) SetCatalogSort(flag bool) {
 	f.catalogSort = flag
 }
 
+// SetDefaultCreationDate sets the default value of the document creation date
+// that will be used when initializing a new Fpdf instance. See
+// SetCreationDate() for more details.
+func SetDefaultCreationDate(tm time.Time) {
+	gl.creationDate = tm
+}
+
 // SetCreationDate fixes the document's internal CreationDate value. By
 // default, the time when the document is generated is used for this value.
 // This method is typically only used for testing purposes. Specify a
-// zero-value time to revert to the default behavior
+// zero-value time to revert to the default behavior.
 func (f *Fpdf) SetCreationDate(tm time.Time) {
 	f.creationDate = tm
 }
@@ -3346,9 +3367,22 @@ func (f *Fpdf) putxobjectdict() {
 func (f *Fpdf) putresourcedict() {
 	f.out("/ProcSet [/PDF /Text /ImageB /ImageC /ImageI]")
 	f.out("/Font <<")
-	for _, font := range f.fonts {
-		// 	foreach($this->fonts as $font)
-		f.outf("/F%d %d 0 R", font.I, font.N)
+	{
+		var keyList []string
+		var font fontDefType
+		var key string
+		for key = range f.fonts {
+			keyList = append(keyList, key)
+		}
+		if f.catalogSort {
+			sort.Strings(keyList)
+		}
+		for _, key = range keyList {
+			font = f.fonts[key]
+			// for _, font := range f.fonts {
+			// 	foreach($this->fonts as $font)
+			f.outf("/F%d %d 0 R", font.I, font.N)
+		}
 	}
 	f.out(">>")
 	f.out("/XObject <<")
diff --git a/fpdf_test.go b/fpdf_test.go
index 39cebc0..cc0b91c 100644
--- a/fpdf_test.go
+++ b/fpdf_test.go
@@ -28,6 +28,7 @@ import (
 	"path/filepath"
 	"strconv"
 	"strings"
+	"time"
 
 	"github.com/jung-kurt/gofpdf"
 	"github.com/jung-kurt/gofpdf/internal/example"
@@ -35,6 +36,8 @@ import (
 
 func init() {
 	cleanup()
+	gofpdf.SetDefaultCatalogSort(true)
+	gofpdf.SetDefaultCreationDate(time.Date(2000, 1, 1, 0, 0, 0, 0, time.UTC))
 }
 
 func cleanup() {