implement replace and swap

1 files changed, 30 insertions, 0 deletions

diff --git a/include/qpdf/QPDF.hh b/include/qpdf/QPDF.hh
index 1ef353e7..dc2b4c22 100644
--- a/include/qpdf/QPDF.hh
+++ b/include/qpdf/QPDF.hh
@@ -128,6 +128,36 @@ class QPDF
     QPDF_DLL
     QPDFObjectHandle getObjectByID(int objid, int generation);
 
+    // Replace the object with the given object id with the given
+    // object.  The object handle passed in must be a direct object,
+    // though it may contain references to other indirect objects
+    // within it.  Calling this method can have somewhat confusing
+    // results.  Any existing QPDFObjectHandle instances that point to
+    // the old object and that have been resolved (which happens
+    // automatically if you access them in any way) will continue to
+    // point to the old object even though that object will no longer
+    // be associated with the PDF file.  Note that replacing an object
+    // with QPDFObjectHandle::newNull() effectively removes the object
+    // from the file since a non-existent object is treated as a null
+    // object.
+    QPDF_DLL
+    void replaceObject(int objid, int generation, QPDFObjectHandle);
+
+    // Swap two objects given by ID.  Calling this method can have
+    // confusing results.  After swapping two objects, existing
+    // QPDFObjectHandle instances that reference them will still
+    // reference the same underlying objects, at which point those
+    // existing QPDFObjectHandle instances will have incorrect
+    // information about the object and generation number of those
+    // objects.  While this does not necessarily cause a problem, it
+    // can certainly be confusing.  It is therefore recommended that
+    // you replace any existing QPDFObjectHandle instances that point
+    // to the swapped objects with new ones, possibly by calling
+    // getObjectByID.
+    QPDF_DLL
+    void swapObjects(int objid1, int generation1,
+		     int objid2, int generation2);
+
     // Encryption support
 
     enum encryption_method_e { e_none, e_unknown, e_rc4, e_aes };