/*
* Build a filter for reading raw stream data.
* This is a null filter to constrain reading to the stream length (and to
* allow for other people accessing the file), followed by a decryption
* filter.
*
* orig_num and orig_gen are used purely to seed the encryption.
*/
static fz_stream *
pdf_open_raw_filter(fz_context *ctx, fz_stream *chain, pdf_document *doc, pdf_obj *stmobj, int num, int orig_num, int orig_gen, int offset)
{
int hascrypt;
int len;
if (num > 0 && num < pdf_xref_len(ctx, doc))
{
pdf_xref_entry *entry = pdf_get_xref_entry(ctx, doc, num);
if (entry->stm_buf)
return fz_open_buffer(ctx, entry->stm_buf);
}
/* don't close chain when we close this filter */
fz_keep_stream(ctx, chain);
len = pdf_to_int(ctx, pdf_dict_get(ctx, stmobj, PDF_NAME_Length));
chain = fz_open_null(ctx, chain, len, offset);
hascrypt = pdf_stream_has_crypt(ctx, stmobj);
if (doc->crypt && !hascrypt)
chain = pdf_open_crypt(ctx, chain, doc->crypt, orig_num, orig_gen);
return chain;
}
fz_buffer *
pdf_load_raw_renumbered_stream(fz_context *ctx, pdf_document *doc, int num, int gen, int orig_num, int orig_gen)
{
fz_stream *stm;
pdf_obj *dict;
int len;
fz_buffer *buf;
if (num > 0 && num < pdf_xref_len(ctx, doc))
{
pdf_xref_entry *entry = pdf_get_xref_entry(ctx, doc, num);
if (entry->stm_buf)
return fz_keep_buffer(ctx, entry->stm_buf);
}
dict = pdf_load_object(ctx, doc, num, gen);
len = pdf_to_int(ctx, pdf_dict_get(ctx, dict, PDF_NAME_Length));
pdf_drop_obj(ctx, dict);
stm = pdf_open_raw_renumbered_stream(ctx, doc, num, gen, orig_num, orig_gen);
buf = fz_read_all(ctx, stm, len);
fz_drop_stream(ctx, stm);
return buf;
}
/*
* Build a filter for reading raw stream data.
* This is a null filter to constrain reading to the stream length (and to
* allow for other people accessing the file), followed by a decryption
* filter.
*
* orig_num and orig_gen are used purely to seed the encryption.
*/
static fz_stream *
pdf_open_raw_filter(fz_context *ctx, fz_stream *chain, pdf_document *doc, pdf_obj *stmobj, int num, int *orig_num, int *orig_gen, fz_off_t offset)
{
pdf_xref_entry *x = NULL;
int hascrypt;
int len;
if (num > 0 && num < pdf_xref_len(ctx, doc))
{
x = pdf_get_xref_entry(ctx, doc, num);
*orig_num = x->num;
*orig_gen = x->gen;
if (x->stm_buf)
return fz_open_buffer(ctx, x->stm_buf);
}
else
{
/* We only end up here when called from pdf_open_stream_with_offset to parse new format XRef sections. */
/* New style XRef sections must have generation number 0. */
*orig_num = num;
*orig_gen = 0;
}
/* don't close chain when we close this filter */
fz_keep_stream(ctx, chain);
len = pdf_to_int(ctx, pdf_dict_get(ctx, stmobj, PDF_NAME_Length));
chain = fz_open_null(ctx, chain, len, offset);
hascrypt = pdf_stream_has_crypt(ctx, stmobj);
if (doc->crypt && !hascrypt)
chain = pdf_open_crypt(ctx, chain, doc->crypt, *orig_num, *orig_gen);
return chain;
}
static fz_buffer *
pdf_load_image_stream(fz_context *ctx, pdf_document *doc, int num, int gen, int orig_num, int orig_gen, fz_compression_params *params, int *truncated)
{
fz_stream *stm = NULL;
pdf_obj *dict, *obj;
int i, len, n;
fz_buffer *buf;
fz_var(buf);
if (num > 0 && num < pdf_xref_len(ctx, doc))
{
pdf_xref_entry *entry = pdf_get_xref_entry(ctx, doc, num);
/* Return ref to existing buffer, but only if uncompressed,
* or shortstoppable */
if (can_reuse_buffer(ctx, entry, params))
return fz_keep_buffer(ctx, entry->stm_buf);
}
dict = pdf_load_object(ctx, doc, num, gen);
len = pdf_to_int(ctx, pdf_dict_get(ctx, dict, PDF_NAME_Length));
obj = pdf_dict_get(ctx, dict, PDF_NAME_Filter);
len = pdf_guess_filter_length(len, pdf_to_name(ctx, obj));
n = pdf_array_len(ctx, obj);
for (i = 0; i < n; i++)
len = pdf_guess_filter_length(len, pdf_to_name(ctx, pdf_array_get(ctx, obj, i)));
pdf_drop_obj(ctx, dict);
stm = pdf_open_image_stream(ctx, doc, num, gen, orig_num, orig_gen, params);
fz_try(ctx)
{
if (truncated)
buf = fz_read_best(ctx, stm, len, truncated);
else
buf = fz_read_all(ctx, stm, len);
}
fz_always(ctx)
{
fz_drop_stream(ctx, stm);
}
fz_catch(ctx)
{
fz_rethrow_message(ctx, "cannot read raw stream (%d %d R)", num, gen);
}
return buf;
}