From 710d2e54f0762b7702640766d33b7e0977ba69de Mon Sep 17 00:00:00 2001
From: m-holger <m-holger@kubitscheck.org>
Date: Wed, 26 Jan 2022 01:28:53 +0000
Subject: [PATCH] Allow testing for subtype without specifying type in
 isDictionaryOfType etc

Accept empty string as type parameter in
QPDFObjectHandle::isDictionaryOfType and isStreamOfType
to allow for dictionaries with optional type.
---
 libqpdf/QPDFObjectHandle.cc | 12 +++---------
 qpdf/qpdf-ctest.c           |  2 +-
 qpdf/test_driver.cc         |  5 +++--
 3 files changed, 7 insertions(+), 12 deletions(-)

diff --git a/libqpdf/QPDFObjectHandle.cc b/libqpdf/QPDFObjectHandle.cc
index f2c77dca..2713eb95 100644
--- a/libqpdf/QPDFObjectHandle.cc
+++ b/libqpdf/QPDFObjectHandle.cc
@@ -507,15 +507,9 @@ bool
 QPDFObjectHandle::isDictionaryOfType(std::string const& type,
                                      std::string const& subtype)
 {
-    if (isDictionary() && getKey("/Type").isNameAndEquals(type))
-    {
-        return (subtype == "") ||
-            (hasKey("/Subtype") && getKey("/Subtype").isNameAndEquals(subtype));
-    }
-    else
-    {
-        return false;
-    }
+    return isDictionary() &&
+           (type.empty() || getKey("/Type").isNameAndEquals(type)) &&
+           (subtype.empty() || getKey("/Subtype").isNameAndEquals(subtype));
 }
 
 bool
diff --git a/qpdf/qpdf-ctest.c b/qpdf/qpdf-ctest.c
index 37225a22..e9a7f1a8 100644
--- a/qpdf/qpdf-ctest.c
+++ b/qpdf/qpdf-ctest.c
@@ -724,7 +724,7 @@ static void test25(char const* infile,
     assert(qpdf_oh_is_dictionary_of_type(qpdf, new_dict, "/Test", "/Marvin"));
     assert(! qpdf_oh_is_dictionary_of_type(qpdf, new_dict, "/Test2", ""));
     assert(! qpdf_oh_is_dictionary_of_type(qpdf, new_dict, "/Test", "/M"));
-    assert(! qpdf_oh_is_dictionary_of_type(qpdf, new_dict, "", ""));
+    assert(qpdf_oh_is_dictionary_of_type(qpdf, new_dict, "", ""));
     qpdf_oh new_array = qpdf_oh_new_array(qpdf);
     qpdf_oh_replace_or_remove_key(
         qpdf, new_dict, "/A", qpdf_oh_new_null(qpdf));
diff --git a/qpdf/test_driver.cc b/qpdf/test_driver.cc
index 28f42643..796d51fb 100644
--- a/qpdf/test_driver.cc
+++ b/qpdf/test_driver.cc
@@ -3110,11 +3110,12 @@ static void test_82(QPDF& pdf, char const* arg2)
     assert(dict.isDictionaryOfType( "/Test", ""));
     assert(dict.isDictionaryOfType("/Test"));
     assert(dict.isDictionaryOfType("/Test", "/Marvin"));
+    assert(dict.isDictionaryOfType("", "/Marvin"));
+    assert(dict.isDictionaryOfType("", ""));
     assert(! dict.isDictionaryOfType("/Test2", ""));
     assert(! dict.isDictionaryOfType("/Test2", "/Marvin"));
     assert(! dict.isDictionaryOfType("/Test", "/M"));
-    assert(! dict.isDictionaryOfType("", "/Marvin"));
-    assert(! dict.isDictionaryOfType("", ""));
+    assert(! name.isDictionaryOfType("", ""));
     dict = QPDFObjectHandle::parse("<</A 1 /Type null /Subtype /Marvin>>");
     assert(! dict.isDictionaryOfType("/Test"));
     dict = QPDFObjectHandle::parse("<</A 1 /Type (Test) /Subtype /Marvin>>");