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