Improve readability in CPDF_Parser::ObjectInfo.

Make CPDF_Parser::ObjectInfo::pos a union, since the data is used as an
object number when the object is compressed.

Change-Id: Id7c32759f7411cc80285bb7f3088b5aa6ff5bf05
Reviewed-on: https://pdfium-review.googlesource.com/9570
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Art Snake <art-snake@yandex-team.ru>

1 files changed, 7 insertions, 2 deletions

diff --git a/core/fpdfapi/parser/cpdf_parser.h b/core/fpdfapi/parser/cpdf_parser.h
index 4d78d7052f..ece1e6a2d4 100644
--- a/core/fpdfapi/parser/cpdf_parser.h
+++ b/core/fpdfapi/parser/cpdf_parser.h
@@ -111,8 +111,13 @@ class CPDF_Parser {
  protected:
   struct ObjectInfo {
     ObjectInfo() : pos(0), type(ObjectType::kFree), gennum(0) {}
-
-    FX_FILESIZE pos;
+    // if type is ObjectType::kCompressed the archive_obj_num should be used.
+    // if type is ObjectType::kNotCompressed the pos should be used.
+    // In other cases its are unused.
+    union {
+      FX_FILESIZE pos;
+      FX_FILESIZE archive_obj_num;
+    };
     ObjectType type;
     uint16_t gennum;
   };