/*
* Build a filter for reading raw stream data.
* This is a null filter to constrain reading to the
* stream length, followed by a decryption filter.
*/
static fz_error *
buildrawfilter(fz_filter **filterp, pdf_xref *xref, fz_obj *stmobj, int oid, int gen)
{
fz_error *error;
fz_filter *base;
fz_obj *stmlen;
int len;
stmlen = fz_dictgets(stmobj, "Length");
error = pdf_resolve(&stmlen, xref);
if (error)
return fz_rethrow(error, "cannot resolve stream /Length");
len = fz_toint(stmlen);
fz_dropobj(stmlen);
error = fz_newnullfilter(&base, len);
if (error)
return fz_rethrow(error, "cannot create null filter");
if (xref->crypt)
{
fz_filter *crypt;
fz_filter *pipe;
error = pdf_cryptstream(&crypt, xref->crypt, oid, gen);
if (error)
{
fz_dropfilter(base);
return fz_rethrow(error, "cannot create decryption filter");
}
error = fz_newpipeline(&pipe, base, crypt);
fz_dropfilter(base);
fz_dropfilter(crypt);
if (error)
return fz_rethrow(error, "cannot create pipeline filter");
*filterp = pipe;
}
else
{
*filterp = base;
}
return fz_okay;
}
static fz_error *
writestream(fz_stream *out, pdf_xref *xref, pdf_crypt *encrypt, int oid, int gen)
{
fz_error *error;
fz_stream *dststm;
fz_stream *srcstm;
unsigned char buf[4096];
fz_filter *ef;
int n;
fz_print(out, "stream\n");
if (encrypt)
{
error = pdf_cryptstream(&ef, encrypt, oid, gen);
if (error)
return error;
error = fz_openrfilter(&dststm, ef, out);
fz_dropfilter(ef);
if (error)
return error;
}
else
{
dststm = fz_keepstream(out);
}
error = pdf_openrawstream(&srcstm, xref, oid, gen);
if (error)
goto cleanupdst;
while (1)
{
n = fz_read(srcstm, buf, sizeof buf);
if (n == 0)
break;
if (n < 0)
{
error = fz_ioerror(srcstm);
goto cleanupsrc;
}
n = fz_write(dststm, buf, n);
if (n < 0)
{
error = fz_ioerror(dststm);
goto cleanupsrc;
}
}
fz_dropstream(srcstm);
fz_dropstream(dststm);
fz_print(out, "endstream\n");
return nil;
cleanupsrc:
fz_dropstream(srcstm);
cleanupdst:
fz_dropstream(dststm);
return error;
}