From: Till Kamppeter <till.kamppeter@gmail.com>
Date: Fri, 22 Jul 2016 09:33:04 +0200
Subject: Workaround patch for missing Python3 transition of the old
 (pre-USB-storage) photo memory card support (pcardext) as this part builds
 in Python3 environments but with pointer-related warnings which are fatal
 errors for Ubuntu's build servers. The patch silences the warnings but the
 memory card support is dropped in Python3 environments. This patch is
 supplied by the HPLIP upstream developers and will be replaced by a more
 proper solution in the next upstream release of HPLIP (see LP: #1275353)

---
 pcard/pcardext/pcardext.c | 59 +++++++++++++++++++++++++++++++++++++----------
 pcard/photocard.py        |  2 +-
 unload.py                 |  5 ++++
 3 files changed, 53 insertions(+), 13 deletions(-)

diff --git a/pcard/pcardext/pcardext.c b/pcard/pcardext/pcardext.c
index c1a8273..37d979b 100644
--- a/pcard/pcardext/pcardext.c
+++ b/pcard/pcardext/pcardext.c
@@ -20,7 +20,7 @@ pcardext - Python extension for HP photocard services
 Requires:
 Python 2.2+
 
-Author: Don Welch
+Author: Don Welch 
 
 \*****************************************************************************/
 
@@ -38,9 +38,37 @@ typedef int Py_ssize_t;
 
 int verbose=0;
 
+#if PY_MAJOR_VERSION >= 3
+  #define MOD_ERROR_VAL NULL
+  #define MOD_SUCCESS_VAL(val) val
+  #define MOD_INIT(name) PyMODINIT_FUNC PyInit_##name(void)
+  #define PyInt_AS_LONG PyLong_AS_LONG
+  #define MOD_DEF(ob, name, doc, methods) \
+          static struct PyModuleDef moduledef = { \
+            PyModuleDef_HEAD_INIT, name, doc, -1, methods, }; \
+          ob = PyModule_Create(&moduledef);
+
+
+  #define PY_String_Bytes  PyBytes_FromStringAndSize
+  #define PY_AsString_Bytes  PyBytes_AsStringAndSize
+
+#else
+  #define MOD_ERROR_VAL
+  #define MOD_SUCCESS_VAL(val)
+  #define MOD_INIT(name) void init##name(void)
+  #define MOD_DEF(ob, name, doc, methods)         \
+        ob = Py_InitModule3(name, methods, doc);
+
+  #define PY_String_Bytes PyString_FromStringAndSize
+  #define PY_AsString_Bytes PyString_AsStringAndSize
+  
+#endif
+
 PyObject * readsectorFunc = NULL;
 PyObject * writesectorFunc = NULL;
 
+
+
 int ReadSector(int sector, int nsector, void *buf, int size)
 {
     PyObject * result;
@@ -56,9 +84,13 @@ int ReadSector(int sector, int nsector, void *buf, int size)
         if( result )
         {
             Py_ssize_t len = 0;
-            PyString_AsStringAndSize( result, &result_str, &len );
+
+            //PyString_AsStringAndSize( result, &result_str, &len );    
+            //PyBytes_AsStringAndSize( result, &result_str, &len ); 
+            PY_AsString_Bytes( result, &result_str, &len );
             
-            if( len < nsector*FAT_HARDSECT )
+
+	    if( len < nsector*FAT_HARDSECT )
             {
                 goto abort;
             }
@@ -205,7 +237,9 @@ PyObject * pcardext_read( PyObject * self, PyObject * args )
     
     if( FatReadFileExt( name, offset, len, buffer ) == len )
     {
-        return PyString_FromStringAndSize( (char *)buffer, len );
+        // return PyString_FromStringAndSize( (char *)buffer, len );
+        return PY_String_Bytes( (char *)buffer, len );
+        // return PyBytes_FromStringAndSize( (char *)buffer, len );
     }
     else
     {
@@ -233,14 +267,15 @@ static PyMethodDef pcardext_methods[] =
 
 static char pcardext_documentation[] = "Python extension for HP photocard services";
 
-void initpcardext( void )
-{
-    PyObject * mod = Py_InitModule4( "pcardext", pcardext_methods, 
-                                     pcardext_documentation, (PyObject*)NULL, 
-                                     PYTHON_API_VERSION );
-                     
-    if (mod == NULL)
-      return;
+MOD_INIT(pcardext)  {
+
+  PyObject* mod ;
+  MOD_DEF(mod, "pcardext", pcardext_documentation, pcardext_methods);
+  if (mod == NULL)
+    return MOD_ERROR_VAL;
+
+  return MOD_SUCCESS_VAL(mod);
+
 }
 
 
diff --git a/pcard/photocard.py b/pcard/photocard.py
index 913dc4e..2c73158 100644
--- a/pcard/photocard.py
+++ b/pcard/photocard.py
@@ -30,7 +30,7 @@ from base.codes import *
 from base import device, utils, exif
 
 try:
-    from . import pcardext
+    import pcardext
 except ImportError:
     if not os.getenv("HPLIP_BUILD"):
         log.error("PCARDEXT could not be loaded. Please check HPLIP installation.")
diff --git a/unload.py b/unload.py
index 3fdd5a3..ce8b069 100755
--- a/unload.py
+++ b/unload.py
@@ -44,6 +44,11 @@ except ImportError:
 
 # Local
 from base.g import *
+from base.sixext import PY3
+if PY3:
+    log.error("This functionality is not spported in python3 environment.")
+    sys.exit(1)
+
 from base import device, utils, tui, module
 from prnt import cups