/*

 * $LynxId: SGML.h,v 1.46 2012/02/10 18:32:26 tom Exp $

 *			       SGML parse and stream definition for libwww

 *                             SGML AND STRUCTURED STREAMS

 *

 * The SGML parser is a state machine.	It is called for every character

 * of the input stream.	 The DTD data structure contains pointers

 * to functions which are called to implement the actual effect of the

 * text read. When these functions are called, the attribute structures pointed to by the

 * DTD are valid, and the function is passed a pointer to the current tag structure, and an

 * "element stack" which represents the state of nesting within SGML elements.

 *

 * The following aspects are from Dan Connolly's suggestions:  Binary search,

 * Structured object scheme basically, SGML content enum type.

 *

 * (c) Copyright CERN 1991 - See Copyright.html

 *

 */

#ifndef SGML_H

#define SGML_H

#include <HTStream.h>

#include <HTAnchor.h>

#include <LYJustify.h>

#ifdef __cplusplus

extern "C" {

#endif

/*

 *

 * SGML content types

 *

 */ typedef enum {

	SGML_EMPTY,		/* No content. */

	SGML_LITTERAL,		/* Literal character data.  Recognize exact close tag only.

				   Old www server compatibility only!  Not SGML */

	SGML_CDATA,		/* Character data.  Recognize </ only.

				   (But we treat it just as SGML_LITTERAL.) */

	SGML_SCRIPT,		/* Like CDATA, but allow it to be a comment */

	SGML_RCDATA,		/* Replaceable character data. Should recognize </ and &ref;

				   (but we treat it like SGML_MIXED for old times' sake). */

	SGML_MIXED,		/* Elements and parsed character data.

				   Recognize all markup. */

	SGML_ELEMENT,		/* Any data found should be regarded as an error.

				   (But we treat it just like SGML_MIXED.) */

	SGML_PCDATA		/* Should contain no elements but &ref; is parsed.

				   (We treat it like SGML_CDATA wrt. contained tags

				   i.e. pass them on literally, i.e. like we should

				   treat SGML_RCDATA) (added by KW). */

    } SGMLContent;

    typedef struct {

	const char *name;	/* The name of the attribute */

#ifdef USE_PRETTYSRC

	char type;		/* code of the type of the attribute. Code

				   values are in HTMLDTD.h */

#endif

    } attr;

    typedef const attr *AttrList;

    typedef struct {

	const char *name;

	AttrList list;

    } AttrType;

    typedef int TagClass;

    /* textflow */

#define Tgc_FONTlike	0x00001	/* S,STRIKE,I,B,TT,U,BIG,SMALL,STYLE,BLINK;BR,TAB */

#define Tgc_EMlike	0x00002	/* EM,STRONG,DFN,CODE,SAMP,KBD,VAR,CITE,Q,INS,DEL,SPAN,.. */

#define Tgc_MATHlike	0x00004	/* SUB,SUP,MATH,COMMENT */

#define Tgc_Alike	0x00008	/* A */

#define Tgc_formula	0x00010	/* not used until math is supported better... */

    /* used for special structures: forms, tables,... */

#define Tgc_TRlike	0x00020	/* TR and similar */

#define Tgc_SELECTlike	0x00040	/* SELECT,INPUT,TEXTAREA(,...) */

    /* structure */

#define Tgc_FORMlike	0x00080	/* FORM itself */

#define Tgc_Plike	0x00100	/* P,H1..H6,... structures containing text or

				   insertion but not other structures */

#define Tgc_DIVlike	0x00200	/* ADDRESS,FIG,BDO,NOTE,FN,DIV,CENTER;FIG

				   structures which can contain other structures */

#define Tgc_LIlike	0x00400	/* LH,LI,DT,DD;TH,TD structure-like, only valid

				   within certain other structures */

#define Tgc_ULlike	0x00800	/* UL,OL,DL,DIR,MENU;TABLE;XMP,LISTING

				   special in some way, cannot contain (parsed)

				   text directly */

    /* insertions */

#define Tgc_BRlike	0x01000	/* BR,IMG,TAB allowed in any text */

#define Tgc_APPLETlike	0x02000	/* APPLET,OBJECT,EMBED,SCRIPT;BUTTON */

#define Tgc_HRlike	0x04000	/* HR,MARQUEE can contain all kinds of things

				   and/or are not allowed (?) in running text */

#define Tgc_MAPlike	0x08000	/* MAP,AREA some specials that never contain

				   (directly or indirectly) other things than

				   special insertions */

#define Tgc_outer	0x10000	/* HTML,FRAMESET,FRAME,PLAINTEXT; */

#define Tgc_BODYlike	0x20000	/* BODY,BODYTEXT,NOFRAMES,TEXTFLOW; */

#define Tgc_HEADstuff	0x40000	/* HEAD,BASE,STYLE,TITLE; */

    /* special relations */

#define Tgc_same	0x80000

/*

 * Groups for contains-data.

 */

#define Tgc_INLINElike	(Tgc_Alike | Tgc_APPLETlike | Tgc_BRlike | Tgc_EMlike | Tgc_FONTlike | Tgc_SELECTlike)

#define Tgc_LISTlike	(Tgc_LIlike | Tgc_ULlike)

#define Tgc_BLOCKlike	(Tgc_DIVlike | Tgc_LISTlike)

/* Some more properties of tags (or rather, elements) and rules how

   to deal with them. - kw */

    typedef int TagFlags;

#define Tgf_endO	0x00001	/* end tag can be Omitted */

#define Tgf_startO	0x00002	/* start tag can be Omitted */

#define Tgf_mafse	0x00004	/* Make Attribute-Free Start-tag End instead

				   (if found invalid) */

#define Tgf_strict	0x00008	/* Ignore contained invalid elements,

				   don't pass them on; or other variant

				   handling for some content types */

#define Tgf_nreie	0x00010	/* Not Really Empty If Empty,

				   used by color style code */

#define Tgf_frecyc	0x00020	/* Pass element content on in a form that

				   allows recycling, i.e. don't translate to

				   output (display) character set yet (treat

				   content similar to attribute values) */

#define Tgf_nolyspcl	0x00040	/* Don't generate lynx special characters

				   for soft hyphen and various spaces (nbsp,

				   ensp,..) */

/*		A tag structure describes an SGML element.

 *		-----------------------------------------

 *

 *

 *	name		is the string which comes after the tag opener "<".

 *

 *	attributes	points to a zero-terminated array

 *			of attribute names.

 *

 *	litteral	determines how the SGML engine parses the characters

 *			within the element.  If set, tag openers are ignored

 *			except for that which opens a matching closing tag.

 *

 */

    typedef struct _tag HTTag;

    struct _tag {

	const char *name;	/* The name of the tag */

#ifdef USE_COLOR_STYLE

	unsigned name_len;	/* The length of the name */

#endif

#ifdef USE_JUSTIFY_ELTS

	BOOL can_justify;	/* justification allowed? */

#endif

	AttrList attributes;	/* The list of acceptable attributes */

	int number_of_attributes;	/* Number of possible attributes */

	const AttrType *attr_types;

	SGMLContent contents;	/* End only on end tag @@ */

	TagClass tagclass;

	TagClass contains;	/* which classes of elements this one can contain directly */

	TagClass icontains;	/* which classes of elements this one can contain indirectly */

	TagClass contained;	/* in which classes can this tag be contained ? */

	TagClass icontained;	/* in which classes can this tag be indirectly contained ? */

	TagClass canclose;	/* which classes of elements can this one close

				   if something looks wrong ? */

	TagFlags flags;

    };

/*		DTD Information

 *		---------------

 *

 *  Not the whole DTD, but all this parser uses of it.

 */

    typedef struct {

	HTTag *tags;		/* Must be in strcmp order by name */

	int number_of_tags;

	STRING2PTR entity_names;	/* Must be in strcmp order by name */

	size_t number_of_entities;

	/*  "entity_names" table probably unused,

	 *  see comments in HTMLDTD.c near the top

	 */

    } SGML_dtd;

/*	SGML context passed to parsers

*/

    typedef struct _HTSGMLContext *HTSGMLContext;	/* Hidden */

/*__________________________________________________________________________

*/

/*

Structured Object definition

   A structured object is something which can reasonably be represented

   in SGML.  I'll rephrase that.  A structured object is an ordered

   tree-structured arrangement of data which is representable as text.

   The SGML parser outputs to a Structured object.  A Structured object

   can output its contents to another Structured Object.  It's a kind of

   typed stream.  The architecture is largely Dan Conolly's.  Elements and

   entities are passed to the sob by number, implying a knowledge of the

   DTD.	 Knowledge of the SGML syntax is not here, though.

   Superclass: HTStream

   The creation methods will vary on the type of Structured Object.

   Maybe the callerData is enough info to pass along.

 */

    typedef struct _HTStructured HTStructured;

    typedef struct _HTStructuredClass {

	const char *name;	/* Just for diagnostics */

	void (*_free) (HTStructured * me);

	void (*_abort) (HTStructured * me, HTError e);

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

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

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

	/* HTStreamClass ends here */

	int (*start_element) (HTStructured * me, int element_number,

			      const BOOL *attribute_present,

			      STRING2PTR attribute_value,

			      int charset,

			      char **include);

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

			    char **include);

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

    } HTStructuredClass;

/*

  Equivalents to the following functions possibly could be generalised

  into additional HTStructuredClass members.  For now they don't do

  anything target-specific. - kw

  */

    extern BOOLEAN LYCheckForCSI(HTParentAnchor *anchor, char **url);

    extern void LYDoCSI(char *url, const char *comment, char **csi);

    extern BOOLEAN LYCommentHacks(HTParentAnchor *anchor, const char *comment);

/*

Find a Tag by Name

   Returns a pointer to the tag within the DTD.

 */

    extern HTTag *SGMLFindTag(const SGML_dtd * dtd,

			      const char *string);

/*

 * Return the current offset within the file that SGML is parsing

 */

    extern int SGML_offset(void);

/*

Create an SGML parser

 */

/*

 * On entry,

 *	dtd		must point to a DTD structure as defined above

 *	callbacks	must point to user routines.

 *	callData	is returned in callbacks transparently.

 * On exit,

 *		The default tag starter has been processed.

 */

    extern HTStream *SGML_new(const SGML_dtd * dtd,

			      HTParentAnchor *anchor,

			      HTStructured * target);

    extern const HTStreamClass SGMLParser;

#ifdef __cplusplus

}

#endif

#endif				/* SGML_H */