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2.1       frystyk     1: <HTML>
                      2: <HEAD>
                      3: <TITLE>Structured Stream Definition</TITLE>
                      4: </HEAD>
                      5: <BODY>
                      6: 
                      7: <H1>Structured Stream Definition</H1>
                      8: 
                      9: <PRE>
                     10: /*
2.2     ! frystyk    11: **     (c) COPYRIGHT MIT 1995.
2.1       frystyk    12: **     Please first read the full copyright statement in the file COPYRIGH.
                     13: */
                     14: </PRE>
                     15: 
                     16: This module is a part of the <A
                     17: HREF="http://www.w3.org/hypertext/WWW/Library/User/Guide/Guide.html">
                     18: Library of Common Code</A>.
                     19: 
                     20: <PRE>
                     21: #ifndef HTSTRUCT_H
                     22: #define HTSTRUCT_H
                     23: 
                     24: #include "HTStream.h"
                     25: </PRE>
                     26: 
                     27: A structured object is something which can reasonably be represented
                     28: in for eaxmple SGML.  I'll rephrase that.  A structured object is am
                     29: ordered tree-structured arrangement of data which is representable as
                     30: text. An example is the SGML parser which outputs to a
                     31: <CODE>Structured Object</CODE>. A Structured object can output its
                     32: contents to another <CODE>Structured Object</CODE>. It's a kind of
                     33: typed stream. The architecure is largely Dan Conolly's. Elements and
                     34: entities are passed to the sob by number, implying a knowledge of the
                     35: DTD.<P>
                     36: 
                     37: The <CODE>Streuctured Stream</CODE> is a subclass of a <A
                     38: HREF="HTStream.html">Generic Stream Object</A>. As always, we don't
                     39: have classes in basic C so we have to do this by hand! <P>
                     40: 
                     41: <B>NOTE:</B> The <CODE>put_block</CODE> method was <CODE>write</CODE>,
                     42: but this upset systems which had macros for <CODE>write()</CODE>. See
                     43: the <A HREF="HTStream.html">Generic Stream Definition</A> for valid
                     44: return codes.<P>
                     45: 
                     46: <PRE>
                     47: typedef struct _HTStructured HTStructured;
                     48: 
                     49: typedef struct _HTStructuredClass {
                     50: 
                     51:     char * name;
                     52: 
                     53:     int (*flush)               PARAMS((HTStructured *  me));
                     54: 
                     55:     int (*_free)               PARAMS((HTStructured *  me));
                     56: 
                     57:     int (*abort)               PARAMS((HTStructured *  me, HTError e));
                     58: 
                     59:     int (*put_character)       PARAMS((HTStructured *  me,
                     60:                                        char            ch));
                     61: 
                     62:     int (*put_string)          PARAMS((HTStructured *  me,
                     63:                                        CONST char *    str));
                     64: 
                     65:     int (*put_block)           PARAMS((HTStructured *  me,
                     66:                                        CONST char *    str,
                     67:                                        int             len));
                     68: </PRE>
                     69: 
                     70: See the <A HREF="HTStream.html">Generic Stream Definition</A> for an
                     71: explanation of these methods. Note that they all have a
                     72: <CODE>HTStructured</CODE> object a the parameter, not a generic
                     73: stream. This is to avoid <EM>incompatible pointer</EM> warnings
                     74: 
                     75: <PRE>
                     76:     void (*start_element)      PARAMS((HTStructured *  me,
                     77:                                        int             element_number,
                     78:                                        CONST BOOL *    attribute_present,
                     79:                                        CONST char **   attribute_value));
                     80: 
                     81:     void (*end_element)                PARAMS((HTStructured *  me,
                     82:                                        int             element_number));
                     83: 
                     84:     void (*put_entity)         PARAMS((HTStructured *  me,
                     85:                                        int             entity_number));
                     86:                
                     87: } HTStructuredClass;
                     88: 
                     89: #endif
                     90: </PRE>
                     91: End of Structured Stream definition
                     92: </BODY>
                     93: </HTML>
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