commit 12f7dcb8071f3925539277d7b96de0efbe5eacd3
author Lei Zhang <thestig@chromium.org> Wed Jun 14 20:50:51 2023 +0000
committer Pdfium LUCI CQ <pdfium-scoped@luci-project-accounts.iam.gserviceaccount.com> Wed Jun 14 20:50:51 2023 +0000
tree 40de08ee3e2fd140df0c15979fa7e80f2ae43583
parent e70dfbc6b8d1031c904e29ed3acbb184f546e360

Document default type value in CPDF_Parser::ProcessCrossRefV5Entry()

Reference the PDF spec and explain why the default object type in
CPDF_Parser::ProcessCrossRefV5Entry() is set as such.

Change-Id: Ie11f1053f6092a39accc52a5e64ee953207fa454
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/108770
Commit-Queue: Lei Zhang <thestig@chromium.org>
Reviewed-by: Nigi <nigi@chromium.org>

core/fpdfapi/parser/cpdf_parser.cpp

diff --git a/core/fpdfapi/parser/cpdf_parser.cpp b/core/fpdfapi/parser/cpdf_parser.cpp
index 39324f2..b1f591d 100644
--- a/core/fpdfapi/parser/cpdf_parser.cpp
+++ b/core/fpdfapi/parser/cpdf_parser.cpp
@@ -839,13 +839,18 @@
     pdfium::span<const uint32_t> field_widths,
     uint32_t obj_num) {
   DCHECK_GE(field_widths.size(), kMinFieldCount);
-  ObjectType type = ObjectType::kNotCompressed;
+  ObjectType type;
   if (field_widths[0]) {
     const uint32_t cross_ref_stream_obj_type =
         GetFirstXRefStreamEntry(entry_span, field_widths);
     type = GetObjectTypeFromCrossRefStreamType(cross_ref_stream_obj_type);
     if (type == ObjectType::kNull)
       return;
+  } else {
+    // Per ISO 32000-1:2008 table 17, use the default value of 1 for the xref
+    // stream entry when it is not specified. The `type` assignment is the
+    // equivalent to calling GetObjectTypeFromCrossRefStreamType(1).
+    type = ObjectType::kNotCompressed;
   }
 
   const ObjectType existing_type = GetObjectType(obj_num);