1 files changed, 24 insertions, 0 deletions
diff --git a/libqpdf/QPDFObjectHandle.cc b/libqpdf/QPDFObjectHandle.cc
index b802a55c..4e77bbaa 100644
--- a/libqpdf/QPDFObjectHandle.cc
+++ b/libqpdf/QPDFObjectHandle.cc
@@ -931,6 +931,30 @@ QPDFObjectHandle::getResourceNames()
     return result;
 }
 
+std::string
+QPDFObjectHandle::getUniqueResourceName(std::string const& prefix,
+                                        int& min_suffix)
+{
+    std::set<std::string> names = getResourceNames();
+    int max_suffix = min_suffix + names.size();
+    while (min_suffix <= max_suffix)
+    {
+        std::string candidate = prefix + QUtil::int_to_string(min_suffix);
+        if (names.count(candidate) == 0)
+        {
+            return candidate;
+        }
+        // Increment after return; min_suffix should be the value
+        // used, not the next value.
+        ++min_suffix;
+    }
+    // This could only happen if there is a coding error.
+    // The number of candidates we test is more than the
+    // number of keys we're checking against.
+    throw std::logic_error("unable to find unconflicting name in"
+                           " QPDFObjectHandle::getUniqueResourceName");
+}
+
 // Indirect object accessors
 QPDF*
 QPDFObjectHandle::getOwningQPDF()