Add JSON::isDictionary and JSON::isArray

ChangeLog

@@ -4,6 +4,10 @@
 	to QPDFObjectHandle with corresponding functions added to the C
 	API. Thanks to m-holger for the contribution.
 
+2022-01-17  Jay Berkenbilt  <ejb@ql.org>
+
+	* Add isDictionary and isArray to JSON
+
 2022-01-11  Jay Berkenbilt  <ejb@ql.org>
 
 	* Bug fix: add missing characters from PDF doc encoding.

include/qpdf/JSON.hh

@@ -69,6 +69,12 @@ class JSON
     QPDF_DLL
     static JSON makeNull();
 
+    QPDF_DLL
+    bool isArray() const;
+
+    QPDF_DLL
+    bool isDictionary() const;
+
     // Check this JSON object against a "schema". This is not a schema
     // according to any standard. It's just a template of what the
     // JSON is supposed to contain. The checking does the following:

libqpdf/JSON.cc

@@ -293,6 +293,20 @@ JSON::makeNull()
     return JSON(new JSON_null());
 }
 
+bool
+JSON::isArray() const
+{
+    return nullptr != dynamic_cast<JSON_array const*>(
+        this->m->value.getPointer());
+}
+
+bool
+JSON::isDictionary() const
+{
+    return nullptr != dynamic_cast<JSON_dictionary const*>(
+        this->m->value.getPointer());
+}
+
 bool
 JSON::checkSchema(JSON schema, std::list<std::string>& errors)
 {