diff --git a/examples/pdf-custom-filter.cc b/examples/pdf-custom-filter.cc
index 2cc4199..1cd4665 100644
--- a/examples/pdf-custom-filter.cc
+++ b/examples/pdf-custom-filter.cc
@@ -1,3 +1,5 @@
+
+#include <qpdf/QIntC.hh>
 #include <qpdf/QPDF.hh>
 #include <qpdf/QPDFStreamFilter.hh>
 #include <qpdf/QPDFWriter.hh>
diff --git a/include/qpdf/QPDF.hh b/include/qpdf/QPDF.hh
index dba648b..1ac5351 100644
--- a/include/qpdf/QPDF.hh
+++ b/include/qpdf/QPDF.hh
@@ -37,7 +37,6 @@
 #include <qpdf/Buffer.hh>
 #include <qpdf/InputSource.hh>
 #include <qpdf/PDFVersion.hh>
-#include <qpdf/QIntC.hh>
 #include <qpdf/QPDFExc.hh>
 #include <qpdf/QPDFObjGen.hh>
 #include <qpdf/QPDFObjectHandle.hh>
@@ -803,32 +802,6 @@ class QPDF
     // JSON import
     void importJSON(std::shared_ptr<InputSource>, bool must_be_complete);
 
-    // Type conversion helper methods
-    template <typename T>
-    static qpdf_offset_t
-    toO(T const& i)
-    {
-        return QIntC::to_offset(i);
-    }
-    template <typename T>
-    static size_t
-    toS(T const& i)
-    {
-        return QIntC::to_size(i);
-    }
-    template <typename T>
-    static int
-    toI(T const& i)
-    {
-        return QIntC::to_int(i);
-    }
-    template <typename T>
-    static unsigned long long
-    toULL(T const& i)
-    {
-        return QIntC::to_ulonglong(i);
-    }
-
     class Members;
 
     // Keep all member variables inside the Members object, which we dynamically allocate. This
diff --git a/libqpdf/QPDF.cc b/libqpdf/QPDF.cc
index c9669b5..07faa88 100644
--- a/libqpdf/QPDF.cc
+++ b/libqpdf/QPDF.cc
@@ -761,7 +761,10 @@ QPDF::pipeStreamData(
         auto buf = file->read(length, offset);
         if (buf.size() != length) {
             throw qpdf_for_warning.m->c.damagedPDF(
-                *file, "", offset + toO(buf.size()), "unexpected EOF reading stream data");
+                *file,
+                "",
+                offset + QIntC::to_offset(buf.size()),
+                "unexpected EOF reading stream data");
         }
         pipeline->write(buf.data(), length);
         attempted_finish = true;
diff --git a/libqpdf/QPDF_encryption.cc b/libqpdf/QPDF_encryption.cc
index 5a0f2c0..e0fe8dc 100644
--- a/libqpdf/QPDF_encryption.cc
+++ b/libqpdf/QPDF_encryption.cc
@@ -1010,7 +1010,7 @@ QPDF::decryptString(std::string& str, QPDFObjGen og)
             // Using std::shared_ptr guarantees that tmp will be freed even if rc4.process throws an
             // exception.
             auto tmp = QUtil::make_unique_cstr(str);
-            RC4 rc4(QUtil::unsigned_char_pointer(key), toI(key.length()));
+            RC4 rc4(QUtil::unsigned_char_pointer(key), QIntC::to_int(key.length()));
             auto data = QUtil::unsigned_char_pointer(tmp.get());
             rc4.process(data, vlen, data);
             str = std::string(tmp.get(), vlen);
diff --git a/libqpdf/QPDF_objects.cc b/libqpdf/QPDF_objects.cc
index b8c43dc..b5653bc 100644
--- a/libqpdf/QPDF_objects.cc
+++ b/libqpdf/QPDF_objects.cc
@@ -1138,7 +1138,7 @@ QPDF::getObjectCount()
     if (!m->obj_cache.empty()) {
         og = (*(m->obj_cache.rbegin())).first;
     }
-    return toS(og.getObj());
+    return QIntC::to_size(og.getObj());
 }
 
 std::vector<QPDFObjectHandle>
diff --git a/libqpdf/qpdf/QPDF_private.hh b/libqpdf/qpdf/QPDF_private.hh
index 895b06f..fdc38c2 100644
--- a/libqpdf/qpdf/QPDF_private.hh
+++ b/libqpdf/qpdf/QPDF_private.hh
@@ -3,6 +3,7 @@
 
 #include <qpdf/QPDF.hh>
 
+#include <qpdf/QIntC.hh>
 #include <qpdf/QPDFAcroFormDocumentHelper.hh>
 #include <qpdf/QPDFEmbeddedFileDocumentHelper.hh>
 #include <qpdf/QPDFLogger.hh>
@@ -323,13 +324,39 @@ class QPDF::Doc
         }
 
       protected:
+        // Type conversion helper methods
+        template <typename T>
+        static qpdf_offset_t
+        toO(T const& i)
+        {
+            return QIntC::to_offset(i);
+        }
+        template <typename T>
+        static size_t
+        toS(T const& i)
+        {
+            return QIntC::to_size(i);
+        }
+        template <typename T>
+        static int
+        toI(T const& i)
+        {
+            return QIntC::to_int(i);
+        }
+        template <typename T>
+        static unsigned long long
+        toULL(T const& i)
+        {
+            return QIntC::to_ulonglong(i);
+        }
+
         QPDF& qpdf;
         QPDF::Members* m;
 
         qpdf::Doc::Config& cf;
         QPDF::Doc::Pages& pages;
         QPDF::Doc::Objects& objects;
-    };
+    }; // class qpdf::Doc::Common
 
     Doc() = delete;
     Doc(Doc const&) = delete;