Tryanks/pdfsign
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Fixes and support for ApprovalSignature and TimeStampSignature

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This commit is contained in:
Paul van Brouwershaven
2024-11-14 13:00:58 +01:00
parent 0899875647
commit 7946d5266d
20 changed files with 1204 additions and 841 deletions
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27
sign/pdftrailer.go
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@@ -6,7 +6,6 @@ import (
)
func (context *SignContext) writeTrailer() error {
if context.PDFReader.XrefInformation.Type == "table" {
trailer_length := context.PDFReader.XrefInformation.IncludingTrailerEndPos - context.PDFReader.XrefInformation.EndPos
@@ -23,18 +22,28 @@ func (context *SignContext) writeTrailer() error {
new_root := "Root " + strconv.FormatInt(int64(context.CatalogData.ObjectId), 10) + " 0 R"
size_string := "Size " + strconv.FormatInt(context.PDFReader.XrefInformation.ItemCount, 10)
new_size := "Size " + strconv.FormatInt(context.PDFReader.XrefInformation.ItemCount+4, 10)
new_size := "Size " + strconv.FormatInt(context.PDFReader.XrefInformation.ItemCount+3, 10)
info := context.PDFReader.Trailer().Key("Info")
infoPtr := info.GetPtr()
info_string := "Info " + strconv.Itoa(int(infoPtr.GetID())) + " " + strconv.Itoa(int(infoPtr.GetGen())) + " R"
new_info := "Info " + strconv.FormatInt(int64(context.InfoData.ObjectId), 10) + " 0 R"
prev_string := "Prev " + context.PDFReader.Trailer().Key("Prev").String()
new_prev := "Prev " + strconv.FormatInt(context.PDFReader.XrefInformation.StartPos, 10)
trailer_string := string(trailer_buf)
trailer_string = strings.Replace(trailer_string, root_string, new_root, -1)
trailer_string = strings.Replace(trailer_string, size_string, new_size, -1)
trailer_string = strings.Replace(trailer_string, info_string, new_info, -1)
if strings.Contains(trailer_string, prev_string) {
trailer_string = strings.Replace(trailer_string, prev_string, new_prev, -1)
} else {
trailer_string = strings.Replace(trailer_string, new_root, new_root+"\n /"+new_prev, -1)
}
// Ensure the same amount of padding (two spaces) for each line, except when the line does not start with a whitespace already.
lines := strings.Split(trailer_string, "\n")
for i, line := range lines {
if strings.HasPrefix(line, " ") {
lines[i] = " " + strings.TrimSpace(line)
}
}
trailer_string = strings.Join(lines, "\n")
// Write the new trailer.
if _, err := context.OutputBuffer.Write([]byte(trailer_string)); err != nil {
@@ -48,7 +57,7 @@ func (context *SignContext) writeTrailer() error {
}
// Write PDF ending.
if _, err := context.OutputBuffer.Write([]byte("%%EOF")); err != nil {
if _, err := context.OutputBuffer.Write([]byte("%%EOF\n")); err != nil {
return err
}