common/sfio/sfstack.c

	sfstack.c revision 1
df8bdeb362277e8d95a74d6c097341fe97409948johnz/***********************************************************************
df8bdeb362277e8d95a74d6c097341fe97409948johnz*                                                                      *
df8bdeb362277e8d95a74d6c097341fe97409948johnz*               This software is part of the ast package               *
df8bdeb362277e8d95a74d6c097341fe97409948johnz*          Copyright (c) 1985-2011 AT&T Intellectual Property          *
df8bdeb362277e8d95a74d6c097341fe97409948johnz*                      and is licensed under the                       *
df8bdeb362277e8d95a74d6c097341fe97409948johnz*                  Common Public License, Version 1.0                  *
df8bdeb362277e8d95a74d6c097341fe97409948johnz*                    by AT&T Intellectual Property                     *
df8bdeb362277e8d95a74d6c097341fe97409948johnz*                                                                      *
df8bdeb362277e8d95a74d6c097341fe97409948johnz*                A copy of the License is available at                 *
df8bdeb362277e8d95a74d6c097341fe97409948johnz*            http://www.opensource.org/licenses/cpl1.0.txt             *
df8bdeb362277e8d95a74d6c097341fe97409948johnz*         (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9)         *
df8bdeb362277e8d95a74d6c097341fe97409948johnz*                                                                      *
df8bdeb362277e8d95a74d6c097341fe97409948johnz*              Information and Software Systems Research               *
df8bdeb362277e8d95a74d6c097341fe97409948johnz*                            AT&T Research                             *
df8bdeb362277e8d95a74d6c097341fe97409948johnz*                           Florham Park NJ                            *
df8bdeb362277e8d95a74d6c097341fe97409948johnz*                                                                      *
df8bdeb362277e8d95a74d6c097341fe97409948johnz*                 Glenn Fowler <gsf@research.att.com>                  *
df8bdeb362277e8d95a74d6c097341fe97409948johnz*                  David Korn <dgk@research.att.com>                   *
df8bdeb362277e8d95a74d6c097341fe97409948johnz*                   Phong Vo <kpv@research.att.com>                    *
df8bdeb362277e8d95a74d6c097341fe97409948johnz*                                                                      *
df8bdeb362277e8d95a74d6c097341fe97409948johnz***********************************************************************/
df8bdeb362277e8d95a74d6c097341fe97409948johnz#include    "sfhdr.h"
9b009fc1b553084f6003dcd46b171890049de0ffValerie Bubb Fenwick
df8bdeb362277e8d95a74d6c097341fe97409948johnz
df8bdeb362277e8d95a74d6c097341fe97409948johnz/*  Push/pop streams
df8bdeb362277e8d95a74d6c097341fe97409948johnz**
df8bdeb362277e8d95a74d6c097341fe97409948johnz**  Written by Kiem-Phong Vo.
df8bdeb362277e8d95a74d6c097341fe97409948johnz*/
df8bdeb362277e8d95a74d6c097341fe97409948johnz
df8bdeb362277e8d95a74d6c097341fe97409948johnz#define STKMTXLOCK(f1,f2) \
df8bdeb362277e8d95a74d6c097341fe97409948johnz    { if(f1) SFMTXLOCK(f1); \
df8bdeb362277e8d95a74d6c097341fe97409948johnz      if(f2) SFMTXLOCK(f2); \
df8bdeb362277e8d95a74d6c097341fe97409948johnz    }
df8bdeb362277e8d95a74d6c097341fe97409948johnz#define STKMTXRETURN(f1,f2,rv) \
df8bdeb362277e8d95a74d6c097341fe97409948johnz    { if(f1) SFMTXUNLOCK(f1); \
df8bdeb362277e8d95a74d6c097341fe97409948johnz      if(f2) SFMTXUNLOCK(f2); \
df8bdeb362277e8d95a74d6c097341fe97409948johnz      return(rv); \
df8bdeb362277e8d95a74d6c097341fe97409948johnz    }
df8bdeb362277e8d95a74d6c097341fe97409948johnz
df8bdeb362277e8d95a74d6c097341fe97409948johnz#if __STD_C
df8bdeb362277e8d95a74d6c097341fe97409948johnzSfio_t* sfstack(Sfio_t* f1, Sfio_t* f2)
df8bdeb362277e8d95a74d6c097341fe97409948johnz#else
df8bdeb362277e8d95a74d6c097341fe97409948johnzSfio_t* sfstack(f1,f2)
df8bdeb362277e8d95a74d6c097341fe97409948johnzSfio_t* f1; /* base of stack    */
df8bdeb362277e8d95a74d6c097341fe97409948johnzSfio_t* f2; /* top of stack */
df8bdeb362277e8d95a74d6c097341fe97409948johnz#endif
df8bdeb362277e8d95a74d6c097341fe97409948johnz{
df8bdeb362277e8d95a74d6c097341fe97409948johnz    reg int     n;
df8bdeb362277e8d95a74d6c097341fe97409948johnz    reg Sfio_t* rf;
df8bdeb362277e8d95a74d6c097341fe97409948johnz    reg Sfrsrv_t*   rsrv;
df8bdeb362277e8d95a74d6c097341fe97409948johnz    reg Void_t* mtx;
df8bdeb362277e8d95a74d6c097341fe97409948johnz
df8bdeb362277e8d95a74d6c097341fe97409948johnz    STKMTXLOCK(f1,f2);
df8bdeb362277e8d95a74d6c097341fe97409948johnz
df8bdeb362277e8d95a74d6c097341fe97409948johnz    if(f1 && (f1->mode&SF_RDWR) != f1->mode && _sfmode(f1,0,0) < 0)
9b009fc1b553084f6003dcd46b171890049de0ffValerie Bubb Fenwick        STKMTXRETURN(f1,f2, NIL(Sfio_t*));
df8bdeb362277e8d95a74d6c097341fe97409948johnz    if(f2 && (f2->mode&SF_RDWR) != f2->mode && _sfmode(f2,0,0) < 0)
df8bdeb362277e8d95a74d6c097341fe97409948johnz        STKMTXRETURN(f1,f2, NIL(Sfio_t*));
df8bdeb362277e8d95a74d6c097341fe97409948johnz    if(!f1)
df8bdeb362277e8d95a74d6c097341fe97409948johnz        STKMTXRETURN(f1,f2, f2);
df8bdeb362277e8d95a74d6c097341fe97409948johnz
df8bdeb362277e8d95a74d6c097341fe97409948johnz    /* give access to other internal functions */
df8bdeb362277e8d95a74d6c097341fe97409948johnz    _Sfstack = sfstack;
df8bdeb362277e8d95a74d6c097341fe97409948johnz
df8bdeb362277e8d95a74d6c097341fe97409948johnz    if(f2 == SF_POPSTACK)
df8bdeb362277e8d95a74d6c097341fe97409948johnz    {   if(!(f2 = f1->push))
df8bdeb362277e8d95a74d6c097341fe97409948johnz            STKMTXRETURN(f1,f2, NIL(Sfio_t*));
df8bdeb362277e8d95a74d6c097341fe97409948johnz        f2->mode &= ~SF_PUSH;
df8bdeb362277e8d95a74d6c097341fe97409948johnz    }
df8bdeb362277e8d95a74d6c097341fe97409948johnz    else
df8bdeb362277e8d95a74d6c097341fe97409948johnz    {   if(f2->push)
df8bdeb362277e8d95a74d6c097341fe97409948johnz            STKMTXRETURN(f1,f2, NIL(Sfio_t*));
df8bdeb362277e8d95a74d6c097341fe97409948johnz        if(f1->pool && f1->pool != &_Sfpool && f1->pool != f2->pool &&
df8bdeb362277e8d95a74d6c097341fe97409948johnz           f1 == f1->pool->sf[0])
df8bdeb362277e8d95a74d6c097341fe97409948johnz        {   /* get something else to pool front since f1 will be locked */
df8bdeb362277e8d95a74d6c097341fe97409948johnz            for(n = 1; n < f1->pool->n_sf; ++n)
df8bdeb362277e8d95a74d6c097341fe97409948johnz            {   if(SFFROZEN(f1->pool->sf[n]) )
df8bdeb362277e8d95a74d6c097341fe97409948johnz                    continue;
df8bdeb362277e8d95a74d6c097341fe97409948johnz                (*_Sfpmove)(f1->pool->sf[n],0);
df8bdeb362277e8d95a74d6c097341fe97409948johnz                break;
df8bdeb362277e8d95a74d6c097341fe97409948johnz            }
df8bdeb362277e8d95a74d6c097341fe97409948johnz        }
df8bdeb362277e8d95a74d6c097341fe97409948johnz    }
df8bdeb362277e8d95a74d6c097341fe97409948johnz
df8bdeb362277e8d95a74d6c097341fe97409948johnz    if(f2->pool && f2->pool != &_Sfpool && f2 != f2->pool->sf[0])
df8bdeb362277e8d95a74d6c097341fe97409948johnz        (*_Sfpmove)(f2,0);
df8bdeb362277e8d95a74d6c097341fe97409948johnz
df8bdeb362277e8d95a74d6c097341fe97409948johnz    /* swap streams */
df8bdeb362277e8d95a74d6c097341fe97409948johnz    sfswap(f1,f2);
df8bdeb362277e8d95a74d6c097341fe97409948johnz
df8bdeb362277e8d95a74d6c097341fe97409948johnz    /* but the reserved buffer and mutex must remain the same */
df8bdeb362277e8d95a74d6c097341fe97409948johnz    rsrv = f1->rsrv; f1->rsrv = f2->rsrv; f2->rsrv = rsrv;
df8bdeb362277e8d95a74d6c097341fe97409948johnz    mtx = f1->mutex; f1->mutex = f2->mutex; f2->mutex = mtx;
df8bdeb362277e8d95a74d6c097341fe97409948johnz
df8bdeb362277e8d95a74d6c097341fe97409948johnz    SFLOCK(f1,0);
df8bdeb362277e8d95a74d6c097341fe97409948johnz    SFLOCK(f2,0);
df8bdeb362277e8d95a74d6c097341fe97409948johnz
df8bdeb362277e8d95a74d6c097341fe97409948johnz    if(f2->push != f2)
df8bdeb362277e8d95a74d6c097341fe97409948johnz    {   /* freeze the pushed stream */
df8bdeb362277e8d95a74d6c097341fe97409948johnz        f2->mode |= SF_PUSH;
df8bdeb362277e8d95a74d6c097341fe97409948johnz        f1->push = f2;
df8bdeb362277e8d95a74d6c097341fe97409948johnz        rf = f1;
df8bdeb362277e8d95a74d6c097341fe97409948johnz    }
df8bdeb362277e8d95a74d6c097341fe97409948johnz    else
df8bdeb362277e8d95a74d6c097341fe97409948johnz    {   /* unfreeze the just exposed stream */
df8bdeb362277e8d95a74d6c097341fe97409948johnz        f1->mode &= ~SF_PUSH;
df8bdeb362277e8d95a74d6c097341fe97409948johnz        f2->push = NIL(Sfio_t*);
df8bdeb362277e8d95a74d6c097341fe97409948johnz        rf = f2;
df8bdeb362277e8d95a74d6c097341fe97409948johnz    }
df8bdeb362277e8d95a74d6c097341fe97409948johnz
df8bdeb362277e8d95a74d6c097341fe97409948johnz    SFOPEN(f1,0);
df8bdeb362277e8d95a74d6c097341fe97409948johnz    SFOPEN(f2,0);
df8bdeb362277e8d95a74d6c097341fe97409948johnz
df8bdeb362277e8d95a74d6c097341fe97409948johnz    STKMTXRETURN(f1,f2, rf);
df8bdeb362277e8d95a74d6c097341fe97409948johnz}
df8bdeb362277e8d95a74d6c097341fe97409948johnz