Пример #1
0
/*
 * 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;
}
Пример #2
0
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;
}
Пример #3
0
/*
 * 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;
}
Пример #4
0
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;
}