// xmlXPathEvalExpression shim around the libxml2 function of the same name
func (xp *Xp) xmlXPathEvalExpression(context *C.xmlNode, path string) (xmlXPathObject *C.xmlXPathObject) {
if context == nil {
context = C.xmlDocGetRootElement(xp.doc)
}
C.xmlXPathSetContextNode(context, xp.xpathCtx)
Cpath := unsafe.Pointer(C.CString(path))
defer C.free(Cpath)
xmlXPathObject = C.xmlXPathEvalExpression((*C.xmlChar)(Cpath), xp.xpathCtx)
return
}
// C14n Canonicalise the node using the SAML specified exclusive method
// Very slow on large documents with node != nil
func (xp *Xp) C14n(node *C.xmlNode) string {
var buffer *C.xmlChar
var nodeset *C.xmlNodeSet
if node != nil {
C.xmlXPathSetContextNode(node, xp.xpathCtx)
xpathObj := C.xmlXPathEvalExpression(exclc14nxpath, xp.xpathCtx)
defer C.xmlXPathFreeObject(xpathObj)
nodeset = xpathObj.nodesetval
//fmt.Printf("%+v\n", nodeset)
}
C.xmlC14NDocDumpMemory(xp.doc, nodeset, C.XML_C14N_EXCLUSIVE_1_0, nil, 0, &buffer)
defer C.free(unsafe.Pointer(buffer))
p := (*C.char)(unsafe.Pointer(buffer))
return C.GoString(p)
}