// pd.stream() returns contents of a stream.
func (pd *PdfReaderT) stream(reference []byte) (DictionaryT, []byte) {
q, d := pd.resolve(reference)
dic := pd.Dic(d)
l := pd.num(dic["/Length"])
pd.rdr.Seek(int64(q), 0)
t, _ := ps.Token(pd.rdr)
if string(t) != "stream" {
return nil, []byte{}
}
ps.SkipLE(pd.rdr)
return dic, pd.rdr.Slice(l)
}
// xrefSkip() queries the start of the trailer for a (partial) xref-table.
func xrefSkip(f fancy.Reader, xref int) int {
f.Seek(int64(xref), 0)
t, p := ps.Token(f)
if string(t) != "xref" {
return -1
}
for {
t, p = ps.Token(f)
if t[0] < '0' || t[0] > '9' {
f.Seek(p, 0)
break
}
t, _ = ps.Token(f)
ps.SkipLE(f)
f.Seek(int64(num(t)*20), 1)
}
r, _ := f.Seek(0, 1)
return int(r)
}
// xrefRead() reads the xref table(s) of a PDF file. This is not recursive
// in favour of not to have to keep track of already used starting points
// for xrefs.
func xrefRead(f fancy.Reader, p int) map[int]int {
var back [MAX_PDF_UPDATES]int
b := 0
s := _Bytes
for ok := true; ok; {
back[b] = p
b++
p = xrefSkip(f, p)
f.Seek(int64(p), 0)
s, _ = ps.Token(f)
if string(s) != "trailer" {
return nil
}
s, _ = ps.Token(f)
s, ok = dictionary(s)["/Prev"]
p = num(s)
}
r := make(map[int]int)
for b != 0 {
b--
f.Seek(int64(back[b]), 0)
ps.Token(f) // skip "xref"
for {
m := tupel(f, 2)
if string(m[0]) == "trailer" {
break
}
ps.SkipLE(f)
o := num(m[0])
dat := f.Slice(num(m[1]) * 20)
for i := 0; i < len(dat); i += 20 {
if dat[i+17] != 'n' {
delete(r, o)
} else {
r[o] = num(dat[i : i+10])
}
o++
}
}
}
return r
}
