The HTML to styled text object converter

/*
**	(c) COPYRIGHT MIT 1995.
**	Please first read the full copyright statement in the file COPYRIGH.
*/
This interprets the HTML semantics and some HTMLPlus.

This module is implemented by HTML.c, and it is a part of the W3C Sample Code Library. 

#ifndef HTML_H
#define HTML_H

#include "HTFormat.h"
#include "HTAnchor.h"
#include "HTMLPDTD.h"

Reopen an Existing HTML object

Reopening an existing HTML object allows it to be retained (for example by the styled text object) after the structured stream has been closed. To be actually deleted, the HTML object must be closed once more times than it has been reopened. 
extern void HTML_reopen (HTStructured * me);

Converters

These are the converters implemented in this module: 
extern HTConverter HTMLToPlain, HTMLToC, HTMLPresent;

Selecting internal character set representations

typedef enum _HTMLCharacterSet {
	HTML_ISO_LATIN1,
	HTML_NEXT_CHARS,
	HTML_PC_CP950
} HTMLCharacterSet;

extern void HTMLUseCharacterSet (HTMLCharacterSet i);

White Space Treatment

There is a small number of different ways of treating white space in SGML, in mapping from a text object to HTML. These have to be programmed it seems. 
/*
In text object	\n\n		\n	tab	\n\n\t
--------------	-------------	-----	-----	-------
in Address,
Blockquote,
Normal,		<P>		<BR>	-		NORMAL
H1-6:		close+open	<BR>	-		HEADING
Glossary	<DT>		<DT>	<DD>	<P>	GLOSSARY
List,				
Menu		<LI>		<LI>	-	<P>	LIST
Dir		<LI>		<LI>	<LI>		DIR
Pre etc		\n\n		\n	\t		PRE

*/

typedef enum _white_space_treatment {
	WS_NORMAL,
	WS_HEADING,
	WS_GLOSSARY,
	WS_LIST,
	WS_DIR,
	WS_PRE
} white_space_treatment;

Nesting State

These elements form tree with an item for each nesting state: that is, each unique combination of nested elements which has a specific style. 
typedef struct _HTNesting {
    void *			style;  /* HTStyle *: Platform dependent */
    white_space_treatment	wst;
    struct _HTNesting *		parent;
    int				element_number;
    int				item_number;	/* only for ordered lists */
    int				list_level;	/* how deep nested */
    HTList *			children;
    BOOL			paragraph_break;
    int				magic;
    BOOL			object_gens_HTML; /* we don't generate HTML */
} HTNesting;

Nesting functions

These functions were new with HTML2.c. They allow the tree of SGML nesting states to be manipulated, and SGML regenerated from the style sequence. 

extern void HTRegenInit (void);

extern void HTRegenCharacter (
	char			c,
	HTNesting *		nesting,
	HTStructured *		target);

extern	void HTNestingChange (
	HTStructured* 	s, 
	HTNesting*		old, 
	HTNesting *		newnest,
	HTChildAnchor *		info,
	const char *		aName);

extern HTNesting * HTMLCommonality (
	HTNesting * 	s1,
	HTNesting *	s2);

extern HTNesting * HTNestElement (HTNesting * p, int ele);
extern /* HTStyle * */ void * HTStyleForNesting (HTNesting * n);

extern HTNesting* HTMLAncestor (HTNesting * old, int depth);

extern HTNesting* CopyBranch (HTNesting * old, HTNesting * newnest,
				     int depth);

extern HTNesting * HTInsertLevel (HTNesting * old,
		int	element_number,
		int	level);
extern HTNesting * HTDeleteLevel (HTNesting * old,
		int	level);
extern int HTMLElementNumber (HTNesting * s);
extern int HTMLLevel ( HTNesting * s);
extern HTNesting* HTMLAncestor (HTNesting * old, int depth);

#endif		/* end HTML_H */
@(#) $Id: HTML.html,v 2.34 1997/02/16 18:42:34 frystyk Exp $