pdf: Drop generation number from public interfaces.

The generation number is only needed for decryption, and is assumed
to be zero or irrelevant for all other uses.

Store the original object number and generation in the xref slot, so
that we can decrypt them even when the objects have been renumbered,
without needing to pass the original object number around through
the stream loading APIs.

1 files changed, 12 insertions, 29 deletions

diff --git a/source/pdf/pdf-write.c b/source/pdf/pdf-write.c
index 1dce7235..aa801b3e 100644
--- a/source/pdf/pdf-write.c
+++ b/source/pdf/pdf-write.c
@@ -68,7 +68,6 @@ struct pdf_write_state_s
 	int *errors;
 	/* The following extras are required for linearization */
 	int *rev_renumber_map;
-	int *rev_gen_list;
 	int start;
 	fz_off_t first_xref_offset;
 	fz_off_t main_xref_offset;
@@ -520,7 +519,6 @@ objects_dump(fz_context *ctx, pdf_document *doc, pdf_write_state *opts)
 static pdf_obj *markref(fz_context *ctx, pdf_document *doc, pdf_write_state *opts, pdf_obj *obj, int *duff)
 {
 	int num = pdf_to_num(ctx, obj);
-	int gen = pdf_to_gen(ctx, obj);
 
 	if (num <= 0 || num >= pdf_xref_len(ctx, doc))
 	{
@@ -536,7 +534,7 @@ static pdf_obj *markref(fz_context *ctx, pdf_document *doc, pdf_write_state *opt
 	/* Bake in /Length in stream objects */
 	fz_try(ctx)
 	{
-		if (pdf_obj_num_is_stream(ctx, doc, num, gen))
+		if (pdf_obj_num_is_stream(ctx, doc, num))
 		{
 			pdf_obj *len = pdf_dict_get(ctx, obj, PDF_NAME_Length);
 			if (pdf_is_indirect(ctx, len))
@@ -653,13 +651,13 @@ static void removeduplicateobjs(fz_context *ctx, pdf_document *doc, pdf_write_st
 			/*
 			 * Comparing stream objects data contents would take too long.
 			 *
-			 * pdf_is_stream calls pdf_cache_object and ensures
+			 * pdf_obj_num_is_stream calls pdf_cache_object and ensures
 			 * that the xref table has the objects loaded.
 			 */
 			fz_try(ctx)
 			{
-				streama = pdf_obj_num_is_stream(ctx, doc, num, 0);
-				streamb = pdf_obj_num_is_stream(ctx, doc, other, 0);
+				streama = pdf_obj_num_is_stream(ctx, doc, num);
+				streamb = pdf_obj_num_is_stream(ctx, doc, other);
 				differ = streama || streamb;
 				if (streama && streamb && opts->do_garbage >= 4)
 					differ = 0;
@@ -695,8 +693,8 @@ static void removeduplicateobjs(fz_context *ctx, pdf_document *doc, pdf_write_st
 				{
 					unsigned char *dataa, *datab;
 					size_t lena, lenb;
-					sa = pdf_load_raw_renumbered_stream(ctx, doc, num, 0, num, 0);
-					sb = pdf_load_raw_renumbered_stream(ctx, doc, other, 0, other, 0);
+					sa = pdf_load_raw_stream(ctx, doc, num);
+					sb = pdf_load_raw_stream(ctx, doc, other);
 					lena = fz_buffer_storage(ctx, sa, &dataa);
 					lenb = fz_buffer_storage(ctx, sb, &datab);
 					if (lena == lenb && memcmp(dataa, datab, lena) == 0)
@@ -758,7 +756,6 @@ static void compactxref(fz_context *ctx, pdf_document *doc, pdf_write_state *opt
 		else if (opts->renumber_map[num] == num)
 		{
 			opts->rev_renumber_map[newnum] = opts->rev_renumber_map[num];
-			opts->rev_gen_list[newnum] = opts->rev_gen_list[num];
 			opts->renumber_map[num] = newnum++;
 		}
 		/* Otherwise it's used, and moved. We know that it must have
@@ -1159,7 +1156,6 @@ add_linearization_objs(fz_context *ctx, pdf_document *doc, pdf_write_state *opts
 		opts->renumber_map[params_num] = params_num;
 		opts->rev_renumber_map[params_num] = params_num;
 		opts->gen_list[params_num] = 0;
-		opts->rev_gen_list[params_num] = 0;
 		pdf_dict_put_drop(ctx, params_obj, PDF_NAME_Linearized, pdf_new_real(ctx, doc, 1.0));
 		opts->linear_l = pdf_new_int(ctx, doc, INT_MIN);
 		pdf_dict_put(ctx, params_obj, PDF_NAME_L, opts->linear_l);
@@ -1187,7 +1183,6 @@ add_linearization_objs(fz_context *ctx, pdf_document *doc, pdf_write_state *opts
 		opts->renumber_map[hint_num] = hint_num;
 		opts->rev_renumber_map[hint_num] = hint_num;
 		opts->gen_list[hint_num] = 0;
-		opts->rev_gen_list[hint_num] = 0;
 		pdf_dict_put_drop(ctx, hint_obj, PDF_NAME_P, pdf_new_int(ctx, doc, 0));
 		opts->hints_s = pdf_new_int(ctx, doc, INT_MIN);
 		pdf_dict_put(ctx, hint_obj, PDF_NAME_S, opts->hints_s);
@@ -1400,7 +1395,6 @@ linearize(fz_context *ctx, pdf_document *doc, pdf_write_state *opts)
 	int n = pdf_xref_len(ctx, doc) + 2;
 	int *reorder;
 	int *rev_renumber_map;
-	int *rev_gen_list;
 
 	opts->page_object_lists = page_objects_list_create(ctx);
 
@@ -1428,7 +1422,6 @@ linearize(fz_context *ctx, pdf_document *doc, pdf_write_state *opts)
 	/* Allocate/init the structures used for renumbering the objects */
 	reorder = fz_calloc(ctx, n, sizeof(int));
 	rev_renumber_map = fz_calloc(ctx, n, sizeof(int));
-	rev_gen_list = fz_calloc(ctx, n, sizeof(int));
 	for (i = 0; i < n; i++)
 	{
 		reorder[i] = i;
@@ -1454,12 +1447,9 @@ linearize(fz_context *ctx, pdf_document *doc, pdf_write_state *opts)
 	{
 		opts->renumber_map[reorder[i]] = i;
 		rev_renumber_map[i] = opts->rev_renumber_map[reorder[i]];
-		rev_gen_list[i] = opts->rev_gen_list[reorder[i]];
 	}
 	fz_free(ctx, opts->rev_renumber_map);
-	fz_free(ctx, opts->rev_gen_list);
 	opts->rev_renumber_map = rev_renumber_map;
-	opts->rev_gen_list = rev_gen_list;
 	fz_free(ctx, reorder);
 
 	/* Apply the renumber_map */
@@ -1511,7 +1501,7 @@ static void preloadobjstms(fz_context *ctx, pdf_document *doc)
 	{
 		if (pdf_get_xref_entry(ctx, doc, num)->type == 'o')
 		{
-			obj = pdf_load_object(ctx, doc, num, 0);
+			obj = pdf_load_object(ctx, doc, num);
 			pdf_drop_obj(ctx, obj);
 		}
 	}
@@ -1641,10 +1631,8 @@ static void copystream(fz_context *ctx, pdf_document *doc, pdf_write_state *opts
 	fz_buffer *buf, *tmp;
 	pdf_obj *newlen;
 	pdf_obj *obj;
-	int orig_num = opts->rev_renumber_map[num];
-	int orig_gen = opts->rev_gen_list[num];
 
-	buf = pdf_load_raw_renumbered_stream(ctx, doc, num, gen, orig_num, orig_gen);
+	buf = pdf_load_raw_stream(ctx, doc, num);
 
 	obj = pdf_copy_dict(ctx, obj_orig);
 
@@ -1687,11 +1675,9 @@ static void expandstream(fz_context *ctx, pdf_document *doc, pdf_write_state *op
 	fz_buffer *buf, *tmp;
 	pdf_obj *newlen;
 	pdf_obj *obj;
-	int orig_num = opts->rev_renumber_map[num];
-	int orig_gen = opts->rev_gen_list[num];
 	int truncated = 0;
 
-	buf = pdf_load_renumbered_stream(ctx, doc, num, gen, orig_num, orig_gen, (opts->continue_on_error ? &truncated : NULL));
+	buf = pdf_load_stream_truncated(ctx, doc, num, (opts->continue_on_error ? &truncated : NULL));
 	if (truncated && opts->errors)
 		(*opts->errors)++;
 
@@ -1802,7 +1788,7 @@ static void writeobject(fz_context *ctx, pdf_document *doc, pdf_write_state *opt
 
 	fz_try(ctx)
 	{
-		obj = pdf_load_object(ctx, doc, num, gen);
+		obj = pdf_load_object(ctx, doc, num);
 	}
 	fz_catch(ctx)
 	{
@@ -1838,7 +1824,7 @@ static void writeobject(fz_context *ctx, pdf_document *doc, pdf_write_state *opt
 	}
 
 	entry = pdf_get_xref_entry(ctx, doc, num);
-	if (!pdf_obj_num_is_stream(ctx, doc, num, gen))
+	if (!pdf_obj_num_is_stream(ctx, doc, num))
 	{
 		fz_printf(ctx, opts->out, "%d %d obj\n", num, gen);
 		pdf_print_obj(ctx, opts->out, obj, opts->do_tight);
@@ -2516,7 +2502,7 @@ make_hint_stream(fz_context *ctx, pdf_document *doc, pdf_write_state *opts)
 	fz_try(ctx)
 	{
 		make_page_offset_hints(ctx, doc, opts, buf);
-		pdf_update_stream(ctx, doc, pdf_load_object(ctx, doc, pdf_xref_len(ctx, doc)-1, 0), buf, 0);
+		pdf_update_stream(ctx, doc, pdf_load_object(ctx, doc, pdf_xref_len(ctx, doc)-1), buf, 0);
 		opts->hintstream_len = (int)buf->len;
 		fz_drop_buffer(ctx, buf);
 	}
@@ -2716,7 +2702,6 @@ static void initialise_write_state(fz_context *ctx, pdf_document *doc, const pdf
 	opts->gen_list = fz_calloc(ctx, xref_len + 3, sizeof(int));
 	opts->renumber_map = fz_malloc_array(ctx, xref_len + 3, sizeof(int));
 	opts->rev_renumber_map = fz_malloc_array(ctx, xref_len + 3, sizeof(int));
-	opts->rev_gen_list = fz_malloc_array(ctx, xref_len + 3, sizeof(int));
 	opts->continue_on_error = in_opts->continue_on_error;
 	opts->errors = in_opts->errors;
 
@@ -2726,7 +2711,6 @@ static void initialise_write_state(fz_context *ctx, pdf_document *doc, const pdf
 		opts->ofs_list[num] = 0;
 		opts->renumber_map[num] = num;
 		opts->rev_renumber_map[num] = num;
-		opts->rev_gen_list[num] = pdf_get_xref_entry(ctx, doc, num)->gen;
 	}
 }
 
@@ -2738,7 +2722,6 @@ static void finalise_write_state(fz_context *ctx, pdf_write_state *opts)
 	fz_free(ctx, opts->gen_list);
 	fz_free(ctx, opts->renumber_map);
 	fz_free(ctx, opts->rev_renumber_map);
-	fz_free(ctx, opts->rev_gen_list);
 	pdf_drop_obj(ctx, opts->linear_l);
 	pdf_drop_obj(ctx, opts->linear_h0);
 	pdf_drop_obj(ctx, opts->linear_h1);