W3C Sample Code Library libwww Structured Stream Class

# Structured Stream Class

    /*
    **	(c) COPYRIGHT MIT 1995.
    **	Please first read the full copyright statement in the file COPYRIGH.
    */

The Structured stream class defines objects which accepts a structured sequence of characters for eaxmple a SGML document. I'll rephrase that. A structured object is am ordered tree-structured arrangement of data which is representable as text. An example is the SGML parser which outputs to a Structured Object. A Structured object can output its contents to another `Structured Object`. It's a kind of typed stream. The architecure is largely Dan Conolly's. Elements and entities are passed to the sob by number, implying a knowledge of the DTD.

The `Structured Stream` is a subclass of a Generic Stream Object. As always, we don't have classes in basic C so we have to do this by hand!

This module is a part of the W3C Sample Code Library.

    #ifndef HTSTRUCT_H
    #define HTSTRUCT_H

    #include "HTStream.h"
    #include "HTList.h"

    typedef struct _HTStructured HTStructured;

    typedef struct _HTStructuredClass {

        char * name;

        int (*flush)	(HTStructured * me);

        int (*_free)	(HTStructured *	me);

        int (*abort)	(HTStructured *	me, HTList * errorlist);

        int (*put_character)(HTStructured *	me, char ch);

        int (*put_string)	(HTStructured *	me, const char * str);

        int (*put_block)	(HTStructured * me, const char * str, int len);

See the Generic Stream Definition for an explanation of these methods. Note that they all have a `HTStructured` object a the parameter, not a generic stream. This is to avoid incompatible pointer warnings

        void (*start_element)(HTStructured *me,
    			  int		element_number,
    			  const BOOL *	attribute_present,
    			  const char **	attribute_value);

        void (*end_element)	(HTStructured *	me, int element_number);

        void (*put_entity)	(HTStructured *	me, int entity_number);

        int (*unparsed_begin_element)(HTStructured * me, const char * str, int len);

        int (*unparsed_end_element)(HTStructured * me, const char * str, int len);

        int (*unparsed_entity)(HTStructured * me, const char * str, int len);

    } HTStructuredClass;

    #endif