1N/A/***********************************************************************
1N/A* *
1N/A* This software is part of the ast package *
1N/A* Copyright (c) 1985-2011 AT&T Intellectual Property *
1N/A* and is licensed under the *
1N/A* Common Public License, Version 1.0 *
1N/A* by AT&T Intellectual Property *
1N/A* *
1N/A* A copy of the License is available at *
1N/A* http://www.opensource.org/licenses/cpl1.0.txt *
1N/A* (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9) *
1N/A* *
1N/A* Information and Software Systems Research *
1N/A* AT&T Research *
1N/A* Florham Park NJ *
1N/A* *
1N/A* Glenn Fowler <gsf@research.att.com> *
1N/A* David Korn <dgk@research.att.com> *
1N/A* Phong Vo <kpv@research.att.com> *
1N/A* *
1N/A***********************************************************************/
1N/A#include "sfhdr.h"
1N/A
1N/A
1N/A/* Push/pop streams
1N/A**
1N/A** Written by Kiem-Phong Vo.
1N/A*/
1N/A
1N/A#define STKMTXLOCK(f1,f2) \
1N/A { if(f1) SFMTXLOCK(f1); \
1N/A if(f2) SFMTXLOCK(f2); \
1N/A }
1N/A#define STKMTXRETURN(f1,f2,rv) \
1N/A { if(f1) SFMTXUNLOCK(f1); \
1N/A if(f2) SFMTXUNLOCK(f2); \
1N/A return(rv); \
1N/A }
1N/A
1N/A#if __STD_C
1N/ASfio_t* sfstack(Sfio_t* f1, Sfio_t* f2)
1N/A#else
1N/ASfio_t* sfstack(f1,f2)
1N/ASfio_t* f1; /* base of stack */
1N/ASfio_t* f2; /* top of stack */
1N/A#endif
1N/A{
1N/A reg int n;
1N/A reg Sfio_t* rf;
1N/A reg Sfrsrv_t* rsrv;
1N/A reg Void_t* mtx;
1N/A
1N/A STKMTXLOCK(f1,f2);
1N/A
1N/A if(f1 && (f1->mode&SF_RDWR) != f1->mode && _sfmode(f1,0,0) < 0)
1N/A STKMTXRETURN(f1,f2, NIL(Sfio_t*));
1N/A if(f2 && (f2->mode&SF_RDWR) != f2->mode && _sfmode(f2,0,0) < 0)
1N/A STKMTXRETURN(f1,f2, NIL(Sfio_t*));
1N/A if(!f1)
1N/A STKMTXRETURN(f1,f2, f2);
1N/A
1N/A /* give access to other internal functions */
1N/A _Sfstack = sfstack;
1N/A
1N/A if(f2 == SF_POPSTACK)
1N/A { if(!(f2 = f1->push))
1N/A STKMTXRETURN(f1,f2, NIL(Sfio_t*));
1N/A f2->mode &= ~SF_PUSH;
1N/A }
1N/A else
1N/A { if(f2->push)
1N/A STKMTXRETURN(f1,f2, NIL(Sfio_t*));
1N/A if(f1->pool && f1->pool != &_Sfpool && f1->pool != f2->pool &&
1N/A f1 == f1->pool->sf[0])
1N/A { /* get something else to pool front since f1 will be locked */
1N/A for(n = 1; n < f1->pool->n_sf; ++n)
1N/A { if(SFFROZEN(f1->pool->sf[n]) )
1N/A continue;
1N/A (*_Sfpmove)(f1->pool->sf[n],0);
1N/A break;
1N/A }
1N/A }
1N/A }
1N/A
1N/A if(f2->pool && f2->pool != &_Sfpool && f2 != f2->pool->sf[0])
1N/A (*_Sfpmove)(f2,0);
1N/A
1N/A /* swap streams */
1N/A sfswap(f1,f2);
1N/A
1N/A /* but the reserved buffer and mutex must remain the same */
1N/A rsrv = f1->rsrv; f1->rsrv = f2->rsrv; f2->rsrv = rsrv;
1N/A mtx = f1->mutex; f1->mutex = f2->mutex; f2->mutex = mtx;
1N/A
1N/A SFLOCK(f1,0);
1N/A SFLOCK(f2,0);
1N/A
1N/A if(f2->push != f2)
1N/A { /* freeze the pushed stream */
1N/A f2->mode |= SF_PUSH;
1N/A f1->push = f2;
1N/A rf = f1;
1N/A }
1N/A else
1N/A { /* unfreeze the just exposed stream */
1N/A f1->mode &= ~SF_PUSH;
1N/A f2->push = NIL(Sfio_t*);
1N/A rf = f2;
1N/A }
1N/A
1N/A SFOPEN(f1,0);
1N/A SFOPEN(f2,0);
1N/A
1N/A STKMTXRETURN(f1,f2, rf);
1N/A}