Skip to content

Added ASCII85 decoder #77

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
pm-phild wants to merge 1 commit into
base: master
Choose a base branch
from
Open

Added ASCII85 decoder #77

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
17 changes: 17 additions & 0 deletions reader.go
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -4,17 +4,21 @@ import (
"bufio"
"bytes"
"compress/zlib"
"encoding/ascii85"
"encoding/binary"
"fmt"
"io"
"io/ioutil"
"math"
"os"
"regexp"
"strconv"

"github.com/pkg/errors"
)

var adobeASCII85 = regexp.MustCompile(`<~|~>`)

type PdfReader struct {
availableBoxes []string
stack []string
Expand Down Expand Up @@ -1436,6 +1440,10 @@ func (this *PdfReader) rebuildContentStream(content *PdfValue) ([]byte, error) {

// Set stream to uncompressed data
stream = out.Bytes()
case "/ASCII85Decode":
if stream, err = uncompressASCII85(stream); err != nil {
return nil, err
}
default:
return nil, errors.New("Unspported filter: " + filters[i].Token)
}
Expand All @@ -1444,6 +1452,15 @@ func (this *PdfReader) rebuildContentStream(content *PdfValue) ([]byte, error) {
return stream, nil
}

func uncompressASCII85(compressed []byte) ([]byte, error) {
// compressed stream may contain <~ and ~> which are not standard ASCII85. Remove them before decoding
compressed = adobeASCII85.ReplaceAll(compressed, []byte{})
var out bytes.Buffer
reader := ascii85.NewDecoder(bytes.NewBuffer(compressed))
io.Copy(&out, reader)
return out.Bytes(), nil
}

func (this *PdfReader) getNumPages() (int, error) {
if this.pageCount == 0 {
return 0, errors.New("Page count is 0")
Expand Down