Abstract: A method and system to efficiently and automatically determine whether a document to be processed and printed has been encoded in a binary or clear text representation of a page description language. The document is initially processed as if it were binary encoded and the first three tags of the document are examined to determine if they contain the object identifier having the value "28 CF 44 00 H". If one of the first three tags has this value, an encoding flag is set to indicate the document is a binary SPDL file and the recognition process is terminated. If the document is determined not to be a binary SPDL file it is examined to see if it is clear text SPDL file. The beginning of the document is examined to determine if it contains zero or more S separators which are defined to be spaces, carriage returns, line feeds, and tabs followed by the characters "<!DOCTYPE" regardless of capitalization followed by one or more S separators followed by the characters "SPDL".

Abstract: An apparatus for controlling printing or display of documents represented in a structured hierarchal page description language. Documents are provided as a document data stream which can include references to external references and external data declarations which can be incorporated into the document by the content processor. Documents are defined by a prologue section which may contain definitions and declaratory commands, with content portions containing specific tokens or command for specific images. The document data stream has a hierarchal structure. A means to provide external declarations is provided which will process external declarations as if the external declaration which can be stored on a separate device were part of the original document data structure. The storage of the references to the external declarations is accomplished in a tree linked stack structure with a last in first out arrangement which allows for a faster search order of external declarations.