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att
GitHub Repository: att/ast
 Path: blob/master/src/lib/libvcodex/vccontext.c
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/***********************************************************************

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*                                                                      *

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*               This software is part of the ast package               *

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*          Copyright (c) 2003-2011 AT&T Intellectual Property          *

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*                      and is licensed under the                       *

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*                 Eclipse Public License, Version 1.0                  *

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*                    by AT&T Intellectual Property                     *

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*                                                                      *

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*                A copy of the License is available at                 *

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*          http://www.eclipse.org/org/documents/epl-v10.html           *

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*         (with md5 checksum b35adb5213ca9657e911e9befb180842)         *

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*                                                                      *

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*              Information and Software Systems Research               *

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*                            AT&T Research                             *

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*                           Florham Park NJ                            *

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*                                                                      *

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*                   Phong Vo <[email protected]>                    *

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*                                                                      *

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***********************************************************************/

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#include	"vchdr.h"

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/*	If a method carries states across vcapply() calls, it needs to

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**	provide a way so that the invoker can set multiple contexts for

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**	transforming data. The below functions create/delete context.

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**

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**	Written by Kiem-Phong Vo ([email protected])

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*/

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#if __STD_C

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Vccontext_t* vcinitcontext(Vcodex_t* vc, Vccontext_t* ctxt)

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#else

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Vccontext_t* vcinitcontext(vc, ctxt)

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Vcodex_t*	vc;

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Vccontext_t*	ctxt;	/* if NULL, make a new one */

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#endif

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{

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	Vccontext_t	*c, *p;

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	if(ctxt)

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	{	for(p = NIL(Vccontext_t*), c = vc->ctxt; c; p = c, c = c->next)

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			if(c == ctxt)

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				break;

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		if(!c) /* non-existing context */

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			return NIL(Vccontext_t*);

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		if(!p) /* already at head of list */

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			return ctxt;

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		else	p->next = ctxt->next;

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	}

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	else

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	{	if(!vc->meth->eventf ||

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		   (*vc->meth->eventf)(vc, VC_INITCONTEXT, (Void_t*)(&ctxt)) < 0 || !ctxt)

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			return NIL(Vccontext_t*);

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	}

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	ctxt->next = vc->ctxt;

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	vc->ctxt = ctxt;

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	return ctxt;

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}

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#if __STD_C

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int vcfreecontext(Vcodex_t* vc, Vccontext_t* ctxt)

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#else

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int vcfreecontext(vc, ctxt)

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Vcodex_t*	vc;

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Vccontext_t*	ctxt; /* if NULL, free all */

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#endif

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{

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	Vccontext_t	*next;

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	if(ctxt)

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	{	if(vcinitcontext(vc, ctxt) != ctxt)

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			return -1;

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		vc->ctxt = ctxt->next;

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		ctxt->next = NIL(Vccontext_t*);

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	}

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	else

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	{	ctxt = vc->ctxt;

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		vc->ctxt = NIL(Vccontext_t*);

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	}

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	for(; ctxt; ctxt = next)

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	{	next = ctxt->next;

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		if(vc->meth->eventf &&

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		   (*vc->meth->eventf)(vc, VC_FREECONTEXT, (Void_t*)ctxt) < 0)

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			return -1;

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	}

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	return 0;

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}

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