Add private methods QPDFObjectHandle::asArray etc

Centralise casting of QPDFObjects and reduce repeated dereferencing.

4 files changed, 287 insertions, 177 deletions

diff --git a/include/qpdf/QPDFObjectHandle.hh b/include/qpdf/QPDFObjectHandle.hh
index 3c7b62f8..af454e75 100644
--- a/include/qpdf/QPDFObjectHandle.hh
+++ b/include/qpdf/QPDFObjectHandle.hh
@@ -43,8 +43,18 @@
 
 class Pipeline;
 class QPDF;
-class QPDF_Dictionary;
 class QPDF_Array;
+class QPDF_Bool;
+class QPDF_Dictionary;
+class QPDF_InlineImage;
+class QPDF_Integer;
+class QPDF_Name;
+class QPDF_Null;
+class QPDF_Operator;
+class QPDF_Real;
+class QPDF_Reserved;
+class QPDF_Stream;
+class QPDF_String;
 class QPDFTokenizer;
 class QPDFExc;
 class Pl_QPDFTokenizer;
@@ -1480,6 +1490,16 @@ class QPDFObjectHandle
             };
             return o.obj;
         }
+        static QPDF_Array*
+        asArray(QPDFObjectHandle& oh)
+        {
+            return oh.asArray();
+        }
+        static QPDF_Stream*
+        asStream(QPDFObjectHandle& oh)
+        {
+            return oh.asStream();
+        }
     };
     friend class ObjAccessor;
 
@@ -1581,6 +1601,20 @@ class QPDFObjectHandle
         qpdf_offset_t offset,
         size_t length);
 
+    QPDF_Array* asArray();
+    QPDF_Bool* asBool();
+    QPDF_Dictionary* asDictionary();
+    QPDF_InlineImage* asInlineImage();
+    QPDF_Integer* asInteger();
+    QPDF_Name* asName();
+    QPDF_Null* asNull();
+    QPDF_Operator* asOperator();
+    QPDF_Real* asReal();
+    QPDF_Reserved* asReserved();
+    QPDF_Stream* asStream();
+    QPDF_Stream* asStreamWithAssert();
+    QPDF_String* asString();
+
     void typeWarning(char const* expected_type, std::string const& warning);
     void objectWarning(std::string const& warning);
     void assertType(char const* type_name, bool istype);
@@ -1881,7 +1915,7 @@ QPDFObjectHandle::setParsedOffset(qpdf_offset_t offset)
 {
     // This is called during parsing on newly created direct objects,
     // so we can't call dereference() here.
-    if (this->obj.get()) {
+    if (initialized) {
         this->obj->setParsedOffset(offset);
     }
 }
diff --git a/libqpdf/QPDF.cc b/libqpdf/QPDF.cc
index 191d98f3..22f62a8b 100644
--- a/libqpdf/QPDF.cc
+++ b/libqpdf/QPDF.cc
@@ -1420,8 +1420,7 @@ QPDF::fixDanglingReferences(bool force)
                 to_check.push_back(iter.second);
             }
         } else if (obj.isArray()) {
-            QPDF_Array* arr = dynamic_cast<QPDF_Array*>(
-                QPDFObjectHandle::ObjAccessor::getObject(obj).get());
+            auto arr = QPDFObjectHandle::ObjAccessor::asArray(obj);
             arr->addExplicitElementsToList(to_check);
         }
         for (auto sub: to_check) {
@@ -2468,12 +2467,12 @@ QPDF::copyStreamData(QPDFObjectHandle result, QPDFObjectHandle foreign)
     QPDFObjGen local_og(result.getObjGen());
     // Copy information from the foreign stream so we can pipe its
     // data later without keeping the original QPDF object around.
+
     QPDF* foreign_stream_qpdf = foreign.getOwningQPDF(
         false, "unable to retrieve owning qpdf from foreign stream");
 
-    QPDF_Stream* stream = dynamic_cast<QPDF_Stream*>(
-        QPDFObjectHandle::ObjAccessor::getObject(foreign).get());
-    if (!stream) {
+    auto stream = QPDFObjectHandle::ObjAccessor::asStream(foreign);
+    if (stream == nullptr) {
         throw std::logic_error("unable to retrieve underlying"
                                " stream object from foreign stream");
     }
diff --git a/libqpdf/QPDFObjectHandle.cc b/libqpdf/QPDFObjectHandle.cc
index f872e984..f60d131a 100644
--- a/libqpdf/QPDFObjectHandle.cc
+++ b/libqpdf/QPDFObjectHandle.cc
@@ -277,24 +277,91 @@ QPDFObjectHandle::getTypeName()
     return dereference() ? this->obj->getTypeName() : "uninitialized";
 }
 
-namespace
+QPDF_Array*
+QPDFObjectHandle::asArray()
 {
-    template <class T>
-    class QPDFObjectTypeAccessor
-    {
-      public:
-        static bool
-        check(std::shared_ptr<QPDFObject> const& o)
-        {
-            return (o && dynamic_cast<T const*>(o.get()));
-        }
-    };
-} // namespace
+    return isArray() ? dynamic_cast<QPDF_Array*>(obj.get()) : nullptr;
+}
+
+QPDF_Bool*
+QPDFObjectHandle::asBool()
+{
+    return isBool() ? dynamic_cast<QPDF_Bool*>(obj.get()) : nullptr;
+}
+
+QPDF_Dictionary*
+QPDFObjectHandle::asDictionary()
+{
+    return isDictionary() ? dynamic_cast<QPDF_Dictionary*>(obj.get()) : nullptr;
+}
+
+QPDF_InlineImage*
+QPDFObjectHandle::asInlineImage()
+{
+    return isInlineImage() ? dynamic_cast<QPDF_InlineImage*>(obj.get())
+                           : nullptr;
+}
+
+QPDF_Integer*
+QPDFObjectHandle::asInteger()
+{
+    return isInteger() ? dynamic_cast<QPDF_Integer*>(obj.get()) : nullptr;
+}
+
+QPDF_Name*
+QPDFObjectHandle::asName()
+{
+    return isName() ? dynamic_cast<QPDF_Name*>(obj.get()) : nullptr;
+}
+
+QPDF_Null*
+QPDFObjectHandle::asNull()
+{
+    return isNull() ? dynamic_cast<QPDF_Null*>(obj.get()) : nullptr;
+}
+
+QPDF_Operator*
+QPDFObjectHandle::asOperator()
+{
+    return isOperator() ? dynamic_cast<QPDF_Operator*>(obj.get()) : nullptr;
+}
+
+QPDF_Real*
+QPDFObjectHandle::asReal()
+{
+    return isReal() ? dynamic_cast<QPDF_Real*>(obj.get()) : nullptr;
+}
+
+QPDF_Reserved*
+QPDFObjectHandle::asReserved()
+{
+    return isReserved() ? dynamic_cast<QPDF_Reserved*>(obj.get()) : nullptr;
+}
+
+QPDF_Stream*
+QPDFObjectHandle::asStream()
+{
+    return isStream() ? dynamic_cast<QPDF_Stream*>(obj.get()) : nullptr;
+}
+
+QPDF_Stream*
+QPDFObjectHandle::asStreamWithAssert()
+{
+    auto stream = asStream();
+    assertType("stream", stream);
+    return stream;
+}
+
+QPDF_String*
+QPDFObjectHandle::asString()
+{
+    return isString() ? dynamic_cast<QPDF_String*>(obj.get()) : nullptr;
+}
 
 bool
 QPDFObjectHandle::isBool()
 {
-    return dereference() && QPDFObjectTypeAccessor<QPDF_Bool>::check(obj);
+    return dereference() && (obj->getTypeCode() == QPDFObject::ot_boolean);
 }
 
 bool
@@ -303,26 +370,26 @@ QPDFObjectHandle::isDirectNull() const
     // Don't call dereference() -- this is a const method, and we know
     // objid == 0, so there's nothing to resolve.
     return (
-        this->initialized && (getObjectID() == 0) &&
-        QPDFObjectTypeAccessor<QPDF_Null>::check(obj));
+        initialized && (getObjectID() == 0) &&
+        (obj->getTypeCode() == QPDFObject::ot_null));
 }
 
 bool
 QPDFObjectHandle::isNull()
 {
-    return dereference() && QPDFObjectTypeAccessor<QPDF_Null>::check(obj);
+    return dereference() && (obj->getTypeCode() == QPDFObject::ot_null);
 }
 
 bool
 QPDFObjectHandle::isInteger()
 {
-    return dereference() && QPDFObjectTypeAccessor<QPDF_Integer>::check(obj);
+    return dereference() && (obj->getTypeCode() == QPDFObject::ot_integer);
 }
 
 bool
 QPDFObjectHandle::isReal()
 {
-    return dereference() && QPDFObjectTypeAccessor<QPDF_Real>::check(obj);
+    return dereference() && (obj->getTypeCode() == QPDFObject::ot_real);
 }
 
 bool
@@ -359,51 +426,49 @@ QPDFObjectHandle::getValueAsNumber(double& value)
 bool
 QPDFObjectHandle::isName()
 {
-    return dereference() && QPDFObjectTypeAccessor<QPDF_Name>::check(obj);
+    return dereference() && (obj->getTypeCode() == QPDFObject::ot_name);
 }
 
 bool
 QPDFObjectHandle::isString()
 {
-    return dereference() && QPDFObjectTypeAccessor<QPDF_String>::check(obj);
+    return dereference() && (obj->getTypeCode() == QPDFObject::ot_string);
 }
 
 bool
 QPDFObjectHandle::isOperator()
 {
-    return dereference() && QPDFObjectTypeAccessor<QPDF_Operator>::check(obj);
+    return dereference() && (obj->getTypeCode() == QPDFObject::ot_operator);
 }
 
 bool
 QPDFObjectHandle::isInlineImage()
 {
-    return dereference() &&
-        QPDFObjectTypeAccessor<QPDF_InlineImage>::check(obj);
+    return dereference() && (obj->getTypeCode() == QPDFObject::ot_inlineimage);
 }
 
 bool
 QPDFObjectHandle::isArray()
 {
-    return dereference() && QPDFObjectTypeAccessor<QPDF_Array>::check(obj);
+    return dereference() && (obj->getTypeCode() == QPDFObject::ot_array);
 }
 
 bool
 QPDFObjectHandle::isDictionary()
 {
-    return dereference() && QPDFObjectTypeAccessor<QPDF_Dictionary>::check(obj);
+    return dereference() && (obj->getTypeCode() == QPDFObject::ot_dictionary);
 }
 
 bool
 QPDFObjectHandle::isStream()
 {
-    return dereference() && QPDFObjectTypeAccessor<QPDF_Stream>::check(obj);
+    return dereference() && (obj->getTypeCode() == QPDFObject::ot_stream);
 }
 
 bool
 QPDFObjectHandle::isReserved()
 {
-    // dereference will clear reserved if this has been replaced
-    return dereference() && QPDFObjectTypeAccessor<QPDF_Reserved>::check(obj);
+    return dereference() && (obj->getTypeCode() == QPDFObject::ot_reserved);
 }
 
 bool
@@ -441,8 +506,9 @@ QPDFObjectHandle::isStreamOfType(
 bool
 QPDFObjectHandle::getBoolValue()
 {
-    if (isBool()) {
-        return dynamic_cast<QPDF_Bool*>(obj.get())->getVal();
+    auto boolean = asBool();
+    if (boolean) {
+        return boolean->getVal();
     } else {
         typeWarning("boolean", "returning false");
         QTC::TC("qpdf", "QPDFObjectHandle boolean returning false");
@@ -453,10 +519,11 @@ QPDFObjectHandle::getBoolValue()
 bool
 QPDFObjectHandle::getValueAsBool(bool& value)
 {
-    if (!isBool()) {
+    auto boolean = asBool();
+    if (boolean == nullptr) {
         return false;
     }
-    value = dynamic_cast<QPDF_Bool*>(obj.get())->getVal();
+    value = boolean->getVal();
     return true;
 }
 
@@ -465,8 +532,9 @@ QPDFObjectHandle::getValueAsBool(bool& value)
 long long
 QPDFObjectHandle::getIntValue()
 {
-    if (isInteger()) {
-        return dynamic_cast<QPDF_Integer*>(obj.get())->getVal();
+    auto integer = asInteger();
+    if (integer) {
+        return integer->getVal();
     } else {
         typeWarning("integer", "returning 0");
         QTC::TC("qpdf", "QPDFObjectHandle integer returning 0");
@@ -477,10 +545,11 @@ QPDFObjectHandle::getIntValue()
 bool
 QPDFObjectHandle::getValueAsInt(long long& value)
 {
-    if (!isInteger()) {
+    auto integer = asInteger();
+    if (integer == nullptr) {
         return false;
     }
-    value = dynamic_cast<QPDF_Integer*>(obj.get())->getVal();
+    value = integer->getVal();
     return true;
 }
 
@@ -576,8 +645,9 @@ QPDFObjectHandle::getValueAsUInt(unsigned int& value)
 std::string
 QPDFObjectHandle::getRealValue()
 {
-    if (isReal()) {
-        return dynamic_cast<QPDF_Real*>(obj.get())->getVal();
+    auto real = asReal();
+    if (real) {
+        return real->getVal();
     } else {
         typeWarning("real", "returning 0.0");
         QTC::TC("qpdf", "QPDFObjectHandle real returning 0.0");
@@ -588,10 +658,11 @@ QPDFObjectHandle::getRealValue()
 bool
 QPDFObjectHandle::getValueAsReal(std::string& value)
 {
-    if (!isReal()) {
+    auto real = asReal();
+    if (real == nullptr) {
         return false;
     }
-    value = dynamic_cast<QPDF_Real*>(obj.get())->getVal();
+    value = real->getVal();
     return true;
 }
 
@@ -600,8 +671,9 @@ QPDFObjectHandle::getValueAsReal(std::string& value)
 std::string
 QPDFObjectHandle::getName()
 {
-    if (isName()) {
-        return dynamic_cast<QPDF_Name*>(obj.get())->getName();
+    auto name = asName();
+    if (name) {
+        return name->getName();
     } else {
         typeWarning("name", "returning dummy name");
         QTC::TC("qpdf", "QPDFObjectHandle name returning dummy name");
@@ -612,10 +684,11 @@ QPDFObjectHandle::getName()
 bool
 QPDFObjectHandle::getValueAsName(std::string& value)
 {
-    if (!isName()) {
+    auto name = asName();
+    if (name == nullptr) {
         return false;
     }
-    value = dynamic_cast<QPDF_Name*>(obj.get())->getName();
+    value = name->getName();
     return true;
 }
 
@@ -624,8 +697,9 @@ QPDFObjectHandle::getValueAsName(std::string& value)
 std::string
 QPDFObjectHandle::getStringValue()
 {
-    if (isString()) {
-        return dynamic_cast<QPDF_String*>(obj.get())->getVal();
+    auto str = asString();
+    if (str) {
+        return str->getVal();
     } else {
         typeWarning("string", "returning empty string");
         QTC::TC("qpdf", "QPDFObjectHandle string returning empty string");
@@ -636,18 +710,20 @@ QPDFObjectHandle::getStringValue()
 bool
 QPDFObjectHandle::getValueAsString(std::string& value)
 {
-    if (!isString()) {
+    auto str = asString();
+    if (str == nullptr) {
         return false;
     }
-    value = dynamic_cast<QPDF_String*>(obj.get())->getVal();
+    value = str->getVal();
     return true;
 }
 
 std::string
 QPDFObjectHandle::getUTF8Value()
 {
-    if (isString()) {
-        return dynamic_cast<QPDF_String*>(obj.get())->getUTF8Val();
+    auto str = asString();
+    if (str) {
+        return str->getUTF8Val();
     } else {
         typeWarning("string", "returning empty string");
         QTC::TC("qpdf", "QPDFObjectHandle string returning empty utf8");
@@ -658,10 +734,11 @@ QPDFObjectHandle::getUTF8Value()
 bool
 QPDFObjectHandle::getValueAsUTF8(std::string& value)
 {
-    if (!isString()) {
+    auto str = asString();
+    if (str == nullptr) {
         return false;
     }
-    value = dynamic_cast<QPDF_String*>(obj.get())->getUTF8Val();
+    value = str->getUTF8Val();
     return true;
 }
 
@@ -670,8 +747,9 @@ QPDFObjectHandle::getValueAsUTF8(std::string& value)
 std::string
 QPDFObjectHandle::getOperatorValue()
 {
-    if (isOperator()) {
-        return dynamic_cast<QPDF_Operator*>(obj.get())->getVal();
+    auto op = asOperator();
+    if (op) {
+        return op->getVal();
     } else {
         typeWarning("operator", "returning fake value");
         QTC::TC("qpdf", "QPDFObjectHandle operator returning fake value");
@@ -682,18 +760,20 @@ QPDFObjectHandle::getOperatorValue()
 bool
 QPDFObjectHandle::getValueAsOperator(std::string& value)
 {
-    if (!isOperator()) {
+    auto op = asOperator();
+    if (op == nullptr) {
         return false;
     }
-    value = dynamic_cast<QPDF_Operator*>(obj.get())->getVal();
+    value = op->getVal();
     return true;
 }
 
 std::string
 QPDFObjectHandle::getInlineImageValue()
 {
-    if (isInlineImage()) {
-        return dynamic_cast<QPDF_InlineImage*>(obj.get())->getVal();
+    auto image = asInlineImage();
+    if (image) {
+        return image->getVal();
     } else {
         typeWarning("inlineimage", "returning empty data");
         QTC::TC("qpdf", "QPDFObjectHandle inlineimage returning empty data");
@@ -704,10 +784,11 @@ QPDFObjectHandle::getInlineImageValue()
 bool
 QPDFObjectHandle::getValueAsInlineImage(std::string& value)
 {
-    if (!isInlineImage()) {
+    auto image = asInlineImage();
+    if (image == nullptr) {
         return false;
     }
-    value = dynamic_cast<QPDF_InlineImage*>(obj.get())->getVal();
+    value = image->getVal();
     return true;
 }
 
@@ -722,8 +803,9 @@ QPDFObjectHandle::aitems()
 int
 QPDFObjectHandle::getArrayNItems()
 {
-    if (isArray()) {
-        return dynamic_cast<QPDF_Array*>(obj.get())->getNItems();
+    auto array = asArray();
+    if (array) {
+        return array->getNItems();
     } else {
         typeWarning("array", "treating as empty");
         QTC::TC("qpdf", "QPDFObjectHandle array treating as empty");
@@ -735,11 +817,12 @@ QPDFObjectHandle
 QPDFObjectHandle::getArrayItem(int n)
 {
     QPDFObjectHandle result;
-    if (isArray() && (n < getArrayNItems()) && (n >= 0)) {
-        result = dynamic_cast<QPDF_Array*>(obj.get())->getItem(n);
+    auto array = asArray();
+    if (array && (n < array->getNItems()) && (n >= 0)) {
+        result = array->getItem(n);
     } else {
         result = newNull();
-        if (isArray()) {
+        if (array) {
             objectWarning("returning null for out of bounds array access");
             QTC::TC("qpdf", "QPDFObjectHandle array bounds");
         } else {
@@ -748,7 +831,7 @@ QPDFObjectHandle::getArrayItem(int n)
         }
         QPDF* context = nullptr;
         std::string description;
-        if (this->obj->getDescription(context, description)) {
+        if (obj->getDescription(context, description)) {
             result.setObjectDescription(
                 context,
                 description + " -> null returned from invalid array access");
@@ -760,14 +843,12 @@ QPDFObjectHandle::getArrayItem(int n)
 bool
 QPDFObjectHandle::isRectangle()
 {
-    if (!isArray()) {
-        return false;
-    }
-    if (getArrayNItems() != 4) {
+    auto array = asArray();
+    if ((array == nullptr) || (array->getNItems() != 4)) {
         return false;
     }
     for (int i = 0; i < 4; ++i) {
-        if (!getArrayItem(i).isNumber()) {
+        if (!array->getItem(i).isNumber()) {
             return false;
         }
     }
@@ -777,14 +858,12 @@ QPDFObjectHandle::isRectangle()
 bool
 QPDFObjectHandle::isMatrix()
 {
-    if (!isArray()) {
-        return false;
-    }
-    if (getArrayNItems() != 6) {
+    auto array = asArray();
+    if ((array == nullptr) || (array->getNItems() != 6)) {
         return false;
     }
     for (int i = 0; i < 6; ++i) {
-        if (!getArrayItem(i).isNumber()) {
+        if (!array->getItem(i).isNumber()) {
             return false;
         }
     }
@@ -796,13 +875,14 @@ QPDFObjectHandle::getArrayAsRectangle()
 {
     Rectangle result;
     if (isRectangle()) {
+        auto array = asArray();
         // Rectangle coordinates are always supposed to be llx, lly,
         // urx, ury, but files have been found in the wild where
         // llx > urx or lly > ury.
-        double i0 = getArrayItem(0).getNumericValue();
-        double i1 = getArrayItem(1).getNumericValue();
-        double i2 = getArrayItem(2).getNumericValue();
-        double i3 = getArrayItem(3).getNumericValue();
+        double i0 = array->getItem(0).getNumericValue();
+        double i1 = array->getItem(1).getNumericValue();
+        double i2 = array->getItem(2).getNumericValue();
+        double i3 = array->getItem(3).getNumericValue();
         result = Rectangle(
             std::min(i0, i2),
             std::min(i1, i3),
@@ -817,13 +897,14 @@ QPDFObjectHandle::getArrayAsMatrix()
 {
     Matrix result;
     if (isMatrix()) {
+        auto array = asArray();
         result = Matrix(
-            getArrayItem(0).getNumericValue(),
-            getArrayItem(1).getNumericValue(),
-            getArrayItem(2).getNumericValue(),
-            getArrayItem(3).getNumericValue(),
-            getArrayItem(4).getNumericValue(),
-            getArrayItem(5).getNumericValue());
+            array->getItem(0).getNumericValue(),
+            array->getItem(1).getNumericValue(),
+            array->getItem(2).getNumericValue(),
+            array->getItem(3).getNumericValue(),
+            array->getItem(4).getNumericValue(),
+            array->getItem(5).getNumericValue());
     }
     return result;
 }
@@ -832,8 +913,9 @@ std::vector<QPDFObjectHandle>
 QPDFObjectHandle::getArrayAsVector()
 {
     std::vector<QPDFObjectHandle> result;
-    if (isArray()) {
-        dynamic_cast<QPDF_Array*>(obj.get())->getAsVector(result);
+    auto array = asArray();
+    if (array) {
+        array->getAsVector(result);
     } else {
         typeWarning("array", "treating as empty");
         QTC::TC("qpdf", "QPDFObjectHandle array treating as empty vector");
@@ -846,9 +928,10 @@ QPDFObjectHandle::getArrayAsVector()
 void
 QPDFObjectHandle::setArrayItem(int n, QPDFObjectHandle const& item)
 {
-    if (isArray()) {
+    auto array = asArray();
+    if (array) {
         checkOwnership(item);
-        dynamic_cast<QPDF_Array*>(obj.get())->setItem(n, item);
+        array->setItem(n, item);
     } else {
         typeWarning("array", "ignoring attempt to set item");
         QTC::TC("qpdf", "QPDFObjectHandle array ignoring set item");
@@ -858,11 +941,12 @@ QPDFObjectHandle::setArrayItem(int n, QPDFObjectHandle const& item)
 void
 QPDFObjectHandle::setArrayFromVector(std::vector<QPDFObjectHandle> const& items)
 {
-    if (isArray()) {
+    auto array = asArray();
+    if (array) {
         for (auto const& item: items) {
             checkOwnership(item);
         }
-        dynamic_cast<QPDF_Array*>(obj.get())->setFromVector(items);
+        array->setFromVector(items);
     } else {
         typeWarning("array", "ignoring attempt to replace items");
         QTC::TC("qpdf", "QPDFObjectHandle array ignoring replace items");
@@ -872,8 +956,9 @@ QPDFObjectHandle::setArrayFromVector(std::vector<QPDFObjectHandle> const& items)
 void
 QPDFObjectHandle::insertItem(int at, QPDFObjectHandle const& item)
 {
-    if (isArray()) {
-        dynamic_cast<QPDF_Array*>(obj.get())->insertItem(at, item);
+    auto array = asArray();
+    if (array) {
+        array->insertItem(at, item);
     } else {
         typeWarning("array", "ignoring attempt to insert item");
         QTC::TC("qpdf", "QPDFObjectHandle array ignoring insert item");
@@ -890,9 +975,10 @@ QPDFObjectHandle::insertItemAndGetNew(int at, QPDFObjectHandle const& item)
 void
 QPDFObjectHandle::appendItem(QPDFObjectHandle const& item)
 {
-    if (isArray()) {
+    auto array = asArray();
+    if (array) {
         checkOwnership(item);
-        dynamic_cast<QPDF_Array*>(obj.get())->appendItem(item);
+        array->appendItem(item);
     } else {
         typeWarning("array", "ignoring attempt to append item");
         QTC::TC("qpdf", "QPDFObjectHandle array ignoring append item");
@@ -909,10 +995,11 @@ QPDFObjectHandle::appendItemAndGetNew(QPDFObjectHandle const& item)
 void
 QPDFObjectHandle::eraseItem(int at)
 {
-    if (isArray() && (at < getArrayNItems()) && (at >= 0)) {
-        dynamic_cast<QPDF_Array*>(obj.get())->eraseItem(at);
+    auto array = asArray();
+    if (array && (at < array->getNItems()) && (at >= 0)) {
+        array->eraseItem(at);
     } else {
-        if (isArray()) {
+        if (array) {
             objectWarning("ignoring attempt to erase out of bounds array item");
             QTC::TC("qpdf", "QPDFObjectHandle erase array bounds");
         } else {
@@ -926,8 +1013,9 @@ QPDFObjectHandle
 QPDFObjectHandle::eraseItemAndGetOld(int at)
 {
     auto result = QPDFObjectHandle::newNull();
-    if (isArray() && (at < getArrayNItems()) && (at >= 0)) {
-        result = getArrayItem(at);
+    auto array = asArray();
+    if (array && (at < array->getNItems()) && (at >= 0)) {
+        result = array->getItem(at);
     }
     eraseItem(at);
     return result;
@@ -944,8 +1032,9 @@ QPDFObjectHandle::ditems()
 bool
 QPDFObjectHandle::hasKey(std::string const& key)
 {
-    if (isDictionary()) {
-        return dynamic_cast<QPDF_Dictionary*>(obj.get())->hasKey(key);
+    auto dict = asDictionary();
+    if (dict) {
+        return dict->hasKey(key);
     } else {
         typeWarning(
             "dictionary", "returning false for a key containment request");
@@ -958,15 +1047,16 @@ QPDFObjectHandle
 QPDFObjectHandle::getKey(std::string const& key)
 {
     QPDFObjectHandle result;
-    if (isDictionary()) {
-        result = dynamic_cast<QPDF_Dictionary*>(obj.get())->getKey(key);
+    auto dict = asDictionary();
+    if (dict) {
+        result = dict->getKey(key);
     } else {
         typeWarning("dictionary", "returning null for attempted key retrieval");
         QTC::TC("qpdf", "QPDFObjectHandle dictionary null for getKey");
         result = newNull();
         QPDF* qpdf = nullptr;
         std::string description;
-        if (this->obj->getDescription(qpdf, description)) {
+        if (obj->getDescription(qpdf, description)) {
             result.setObjectDescription(
                 qpdf,
                 (description + " -> null returned from getting key " + key +
@@ -986,8 +1076,9 @@ std::set<std::string>
 QPDFObjectHandle::getKeys()
 {
     std::set<std::string> result;
-    if (isDictionary()) {
-        result = dynamic_cast<QPDF_Dictionary*>(obj.get())->getKeys();
+    auto dict = asDictionary();
+    if (dict) {
+        result = dict->getKeys();
     } else {
         typeWarning("dictionary", "treating as empty");
         QTC::TC("qpdf", "QPDFObjectHandle dictionary empty set for getKeys");
@@ -999,8 +1090,9 @@ std::map<std::string, QPDFObjectHandle>
 QPDFObjectHandle::getDictAsMap()
 {
     std::map<std::string, QPDFObjectHandle> result;
-    if (isDictionary()) {
-        result = dynamic_cast<QPDF_Dictionary*>(obj.get())->getAsMap();
+    auto dict = asDictionary();
+    if (dict) {
+        result = dict->getAsMap();
     } else {
         typeWarning("dictionary", "treating as empty");
         QTC::TC("qpdf", "QPDFObjectHandle dictionary empty map for asMap");
@@ -1191,9 +1283,10 @@ void
 QPDFObjectHandle::replaceKey(
     std::string const& key, QPDFObjectHandle const& value)
 {
-    if (isDictionary()) {
+    auto dict = asDictionary();
+    if (dict) {
         checkOwnership(value);
-        dynamic_cast<QPDF_Dictionary*>(obj.get())->replaceKey(key, value);
+        dict->replaceKey(key, value);
     } else {
         typeWarning("dictionary", "ignoring key replacement request");
         QTC::TC("qpdf", "QPDFObjectHandle dictionary ignoring replaceKey");
@@ -1220,8 +1313,9 @@ QPDFObjectHandle::replaceKeyAndGetOld(
 void
 QPDFObjectHandle::removeKey(std::string const& key)
 {
-    if (isDictionary()) {
-        dynamic_cast<QPDF_Dictionary*>(obj.get())->removeKey(key);
+    auto dict = asDictionary();
+    if (dict) {
+        dict->removeKey(key);
     } else {
         typeWarning("dictionary", "ignoring key removal request");
         QTC::TC("qpdf", "QPDFObjectHandle dictionary ignoring removeKey");
@@ -1232,8 +1326,9 @@ QPDFObjectHandle
 QPDFObjectHandle::removeKeyAndGetOld(std::string const& key)
 {
     auto result = QPDFObjectHandle::newNull();
-    if (isDictionary()) {
-        result = getKey(key);
+    auto dict = asDictionary();
+    if (dict) {
+        result = dict->getKey(key);
     }
     removeKey(key);
     return result;
@@ -1250,50 +1345,43 @@ QPDFObjectHandle::replaceOrRemoveKey(
 QPDFObjectHandle
 QPDFObjectHandle::getDict()
 {
-    assertStream();
-    return dynamic_cast<QPDF_Stream*>(obj.get())->getDict();
+    return asStreamWithAssert()->getDict();
 }
 
 void
 QPDFObjectHandle::setFilterOnWrite(bool val)
 {
-    assertStream();
-    dynamic_cast<QPDF_Stream*>(obj.get())->setFilterOnWrite(val);
+    asStreamWithAssert()->setFilterOnWrite(val);
 }
 
 bool
 QPDFObjectHandle::getFilterOnWrite()
 {
-    assertStream();
-    return dynamic_cast<QPDF_Stream*>(obj.get())->getFilterOnWrite();
+    return asStreamWithAssert()->getFilterOnWrite();
 }
 
 bool
 QPDFObjectHandle::isDataModified()
 {
-    assertStream();
-    return dynamic_cast<QPDF_Stream*>(obj.get())->isDataModified();
+    return asStreamWithAssert()->isDataModified();
 }
 
 void
 QPDFObjectHandle::replaceDict(QPDFObjectHandle const& new_dict)
 {
-    assertStream();
-    dynamic_cast<QPDF_Stream*>(obj.get())->replaceDict(new_dict);
+    asStreamWithAssert()->replaceDict(new_dict);
 }
 
 std::shared_ptr<Buffer>
 QPDFObjectHandle::getStreamData(qpdf_stream_decode_level_e level)
 {
-    assertStream();
-    return dynamic_cast<QPDF_Stream*>(obj.get())->getStreamData(level);
+    return asStreamWithAssert()->getStreamData(level);
 }
 
 std::shared_ptr<Buffer>
 QPDFObjectHandle::getRawStreamData()
 {
-    assertStream();
-    return dynamic_cast<QPDF_Stream*>(obj.get())->getRawStreamData();
+    return asStreamWithAssert()->getRawStreamData();
 }
 
 bool
@@ -1305,8 +1393,7 @@ QPDFObjectHandle::pipeStreamData(
     bool suppress_warnings,
     bool will_retry)
 {
-    assertStream();
-    return dynamic_cast<QPDF_Stream*>(obj.get())->pipeStreamData(
+    return asStreamWithAssert()->pipeStreamData(
         p,
         filtering_attempted,
         encode_flags,
@@ -1323,9 +1410,8 @@ QPDFObjectHandle::pipeStreamData(
     bool suppress_warnings,
     bool will_retry)
 {
-    assertStream();
     bool filtering_attempted;
-    dynamic_cast<QPDF_Stream*>(obj.get())->pipeStreamData(
+    asStreamWithAssert()->pipeStreamData(
         p,
         &filtering_attempted,
         encode_flags,
@@ -1359,9 +1445,7 @@ QPDFObjectHandle::replaceStreamData(
     QPDFObjectHandle const& filter,
     QPDFObjectHandle const& decode_parms)
 {
-    assertStream();
-    dynamic_cast<QPDF_Stream*>(obj.get())->replaceStreamData(
-        data, filter, decode_parms);
+    asStreamWithAssert()->replaceStreamData(data, filter, decode_parms);
 }
 
 void
@@ -1370,14 +1454,12 @@ QPDFObjectHandle::replaceStreamData(
     QPDFObjectHandle const& filter,
     QPDFObjectHandle const& decode_parms)
 {
-    assertStream();
     auto b = std::make_shared<Buffer>(data.length());
     unsigned char* bp = b->getBuffer();
     if (bp) {
         memcpy(bp, data.c_str(), data.length());
     }
-    dynamic_cast<QPDF_Stream*>(obj.get())->replaceStreamData(
-        b, filter, decode_parms);
+    asStreamWithAssert()->replaceStreamData(b, filter, decode_parms);
 }
 
 void
@@ -1386,9 +1468,7 @@ QPDFObjectHandle::replaceStreamData(
     QPDFObjectHandle const& filter,
     QPDFObjectHandle const& decode_parms)
 {
-    assertStream();
-    dynamic_cast<QPDF_Stream*>(obj.get())->replaceStreamData(
-        provider, filter, decode_parms);
+    asStreamWithAssert()->replaceStreamData(provider, filter, decode_parms);
 }
 
 namespace
@@ -1437,11 +1517,9 @@ QPDFObjectHandle::replaceStreamData(
     QPDFObjectHandle const& filter,
     QPDFObjectHandle const& decode_parms)
 {
-    assertStream();
     auto sdp =
         std::shared_ptr<StreamDataProvider>(new FunctionProvider(provider));
-    dynamic_cast<QPDF_Stream*>(obj.get())->replaceStreamData(
-        sdp, filter, decode_parms);
+    asStreamWithAssert()->replaceStreamData(sdp, filter, decode_parms);
 }
 
 void
@@ -1450,11 +1528,9 @@ QPDFObjectHandle::replaceStreamData(
     QPDFObjectHandle const& filter,
     QPDFObjectHandle const& decode_parms)
 {
-    assertStream();
     auto sdp =
         std::shared_ptr<StreamDataProvider>(new FunctionProvider(provider));
-    dynamic_cast<QPDF_Stream*>(obj.get())->replaceStreamData(
-        sdp, filter, decode_parms);
+    asStreamWithAssert()->replaceStreamData(sdp, filter, decode_parms);
 }
 
 std::map<std::string, QPDFObjectHandle>
@@ -1469,10 +1545,11 @@ QPDFObjectHandle::arrayOrStreamToStreamArray(
 {
     all_description = description;
     std::vector<QPDFObjectHandle> result;
-    if (isArray()) {
-        int n_items = getArrayNItems();
+    auto array = asArray();
+    if (array) {
+        int n_items = array->getNItems();
         for (int i = 0; i < n_items; ++i) {
-            QPDFObjectHandle item = getArrayItem(i);
+            QPDFObjectHandle item = array->getItem(i);
             if (item.isStream()) {
                 result.push_back(item);
             } else {
@@ -1649,8 +1726,9 @@ QPDFObjectHandle::unparseResolved()
 std::string
 QPDFObjectHandle::unparseBinary()
 {
-    if (this->isString()) {
-        return dynamic_cast<QPDF_String*>(this->obj.get())->unparse(true);
+    auto str = asString();
+    if (str) {
+        return str->unparse(true);
     } else {
         return unparse();
     }
@@ -1666,7 +1744,7 @@ QPDFObjectHandle::getJSON(bool dereference_indirect)
 JSON
 QPDFObjectHandle::getJSON(int json_version, bool dereference_indirect)
 {
-    if ((!dereference_indirect) && this->isIndirect()) {
+    if ((!dereference_indirect) && isIndirect()) {
         return JSON::makeString(unparse());
     } else if (!dereference()) {
         throw std::logic_error(
@@ -1675,7 +1753,7 @@ QPDFObjectHandle::getJSON(int json_version, bool dereference_indirect)
         throw std::logic_error(
             "QPDFObjectHandle: attempting to unparse a reserved object");
     } else {
-        return this->obj->getJSON(json_version);
+        return obj->getJSON(json_version);
     }
 }
 
@@ -1687,8 +1765,7 @@ QPDFObjectHandle::getStreamJSON(
     Pipeline* p,
     std::string const& data_filename)
 {
-    assertStream();
-    return dynamic_cast<QPDF_Stream*>(obj.get())->getStreamJSON(
+    return asStreamWithAssert()->getStreamJSON(
         json_version, json_data, decode_level, p, data_filename);
 }
 
@@ -1908,8 +1985,7 @@ QPDFObjectHandle::addContentTokenFilter(std::shared_ptr<TokenFilter> filter)
 void
 QPDFObjectHandle::addTokenFilter(std::shared_ptr<TokenFilter> filter)
 {
-    assertStream();
-    return dynamic_cast<QPDF_Stream*>(obj.get())->addTokenFilter(filter);
+    return asStreamWithAssert()->addTokenFilter(filter);
 }
 
 QPDFObjectHandle
@@ -1946,7 +2022,6 @@ QPDFObjectHandle::newIndirect(QPDF* qpdf, QPDFObjGen const& og)
         QTC::TC("qpdf", "QPDFObjectHandle indirect with 0 objid");
         return newNull();
     }
-
     return QPDFObjectHandle(qpdf, og, QPDF_Unresolved::create());
 }
 
@@ -2119,8 +2194,7 @@ QPDFObjectHandle::newStream(QPDF* qpdf)
     QPDFObjectHandle stream_dict = newDictionary();
     QPDFObjectHandle result = qpdf->makeIndirectObject(QPDFObjectHandle(
         QPDF_Stream::create(qpdf, QPDFObjGen(), stream_dict, 0, 0)));
-    result.dereference();
-    QPDF_Stream* stream = dynamic_cast<QPDF_Stream*>(result.obj.get());
+    auto stream = result.asStream();
     stream->setObjGen(result.getObjGen());
     return result;
 }
@@ -2248,9 +2322,10 @@ QPDFObjectHandle::copyObject(
         new_obj = obj->shallowCopy();
     } else if (isArray()) {
         std::vector<QPDFObjectHandle> items;
-        int n = getArrayNItems();
+        auto array = asArray();
+        int n = array->getNItems();
         for (int i = 0; i < n; ++i) {
-            items.push_back(getArrayItem(i));
+            items.push_back(array->getItem(i));
             if ((!first_level_only) &&
                 (cross_indirect || (!items.back().isIndirect()))) {
                 items.back().copyObject(
@@ -2260,8 +2335,9 @@ QPDFObjectHandle::copyObject(
         new_obj = QPDF_Array::create(items);
     } else if (isDictionary()) {
         std::map<std::string, QPDFObjectHandle> items;
+        auto dict = asDictionary();
         for (auto const& key: getKeys()) {
-            items[key] = getKey(key);
+            items[key] = dict->getKey(key);
             if ((!first_level_only) &&
                 (cross_indirect || (!items[key].isIndirect()))) {
                 items[key].copyObject(
@@ -2309,7 +2385,7 @@ QPDFObjectHandle::makeDirect(bool allow_streams)
 void
 QPDFObjectHandle::assertInitialized() const
 {
-    if (!this->initialized) {
+    if (!initialized) {
         throw std::logic_error("operation attempted on uninitialized "
                                "QPDFObjectHandle");
     }
@@ -2551,7 +2627,6 @@ QPDFObjectHandle::dereference()
         (getObjectID() &&
          QPDF::Resolver::objectChanged(this->qpdf, getObjGen(), this->obj))) {
         this->obj = QPDF::Resolver::resolve(this->qpdf, getObjGen());
-
     }
     return true;
 }
diff --git a/libqpdf/QPDF_Reserved.cc b/libqpdf/QPDF_Reserved.cc
index 5808a369..d5009674 100644
--- a/libqpdf/QPDF_Reserved.cc
+++ b/libqpdf/QPDF_Reserved.cc
@@ -17,14 +17,16 @@ QPDF_Reserved::shallowCopy()
 std::string
 QPDF_Reserved::unparse()
 {
-    throw std::logic_error("attempt to unparse QPDF_Reserved");
+    throw std::logic_error(
+        "QPDFObjectHandle: attempting to unparse a reserved object");
     return "";
 }
 
 JSON
 QPDF_Reserved::getJSON(int json_version)
 {
-    throw std::logic_error("attempt to generate JSON from QPDF_Reserved");
+    throw std::logic_error(
+        "QPDFObjectHandle: attempting to unparse a reserved object");
     return JSON::makeNull();
 }