/***	MERGE CLASS STREAM DEFINITION****	(c) COPYRIGHT MIT 1995.**	Please first read the full copyright statement in the file COPYRIGH.**	@(#) $Id: HTMerge.c,v 2.3 1999/02/22 22:10:11 frystyk Exp $****	The Merge class just is a n entry stream. Easy. The reason for having**	this stream is that we must be able to handle free and abort in an**	organized manner.**	You can also check out the. Tee stream and the Black hole stream.**** HISTORY:**	25 Sep 96  HFN	Written*//* Library include files */#include "wwwsys.h"#include "WWWUtil.h"#include "HTMerge.h"struct _HTStream {    const HTStreamClass *	isa;    HTStream *			target;    int				feeds;			  /* Number of feeds */};PRIVATE int HTMerge_putCharacter (HTStream * me, char c){    return (me->feeds > 0) ?	(*me->target->isa->put_character)(me->target, c) : HT_OK;}PRIVATE int HTMerge_putString (HTStream * me, const char * s){    return (me->feeds > 0) ?	(*me->target->isa->put_string)(me->target, s) : HT_OK;}PRIVATE int HTMerge_putBlock (HTStream * me, const char * s, int l){    return (me->feeds > 0) ?	(*me->target->isa->put_block)(me->target, s, l) : HT_OK;}PRIVATE int HTMerge_flush (HTStream * me){    return (me->feeds > 0) ?	(*me->target->isa->flush)(me->target) : HT_OK;}/***  We expect n number of calls to this method but as long as our number**  of feeds is not down to 1, we just ignore it. Abort works the same way*/PRIVATE int HTMerge_free (HTStream * me){    if (me) {	HTTRACE(STREAM_TRACE, "Merge Free.. Called with %d feeds\n" _ me->feeds);	if (--me->feeds <= 0) {	    (*me->target->isa->_free)(me->target);	    HT_FREE(me);	}	return HT_OK;    }    return HT_ERROR;}PRIVATE int HTMerge_abort (HTStream * me, HTList * e){    if (me) {	HTTRACE(STREAM_TRACE, "Merge Abort. Called with %d feeds\n" _ me->feeds);	if (--me->feeds <= 0) {	    (*me->target->isa->abort)(me->target, e);	    HT_FREE(me);	}    }    return HT_ERROR;}PRIVATE const HTStreamClass HTMergeClass ={		    "MergeStream",    HTMerge_flush,    HTMerge_free,    HTMerge_abort,    HTMerge_putCharacter,    HTMerge_putString,    HTMerge_putBlock}; PUBLIC HTStream * HTMerge (HTStream * target, int feeds){    HTStream * me;    if ((me = (HTStream  *) HT_CALLOC(1, sizeof(*me))) == NULL)        HT_OUTOFMEM("HTMerge");    me->isa = &HTMergeClass;    me->target = target ? target : HTBlackHole();    me->feeds = feeds >= 1 ? feeds : 1;			       /* Min 1 feed */    HTTRACE(STREAM_TRACE, "Merge....... Created stream %p\n" _ me);    return me;}