diff options
Diffstat (limited to 'usr/src/lib/libast/common/sfio/sfstack.c')
| -rw-r--r-- | usr/src/lib/libast/common/sfio/sfstack.c | 115 |
1 files changed, 115 insertions, 0 deletions
diff --git a/usr/src/lib/libast/common/sfio/sfstack.c b/usr/src/lib/libast/common/sfio/sfstack.c new file mode 100644 index 0000000000..27012aa23c --- /dev/null +++ b/usr/src/lib/libast/common/sfio/sfstack.c @@ -0,0 +1,115 @@ +/*********************************************************************** +* * +* This software is part of the ast package * +* Copyright (c) 1985-2007 AT&T Knowledge Ventures * +* and is licensed under the * +* Common Public License, Version 1.0 * +* by AT&T Knowledge Ventures * +* * +* A copy of the License is available at * +* http://www.opensource.org/licenses/cpl1.0.txt * +* (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9) * +* * +* Information and Software Systems Research * +* AT&T Research * +* Florham Park NJ * +* * +* Glenn Fowler <gsf@research.att.com> * +* David Korn <dgk@research.att.com> * +* Phong Vo <kpv@research.att.com> * +* * +***********************************************************************/ +#include "sfhdr.h" + + +/* Push/pop streams +** +** Written by Kiem-Phong Vo. +*/ + +#define STKMTXLOCK(f1,f2) \ + { if(f1) SFMTXLOCK(f1); \ + if(f2) SFMTXLOCK(f2); \ + } +#define STKMTXRETURN(f1,f2,rv) \ + { if(f1) SFMTXUNLOCK(f1); \ + if(f2) SFMTXUNLOCK(f2); \ + return(rv); \ + } + +#if __STD_C +Sfio_t* sfstack(Sfio_t* f1, Sfio_t* f2) +#else +Sfio_t* sfstack(f1,f2) +Sfio_t* f1; /* base of stack */ +Sfio_t* f2; /* top of stack */ +#endif +{ + reg int n; + reg Sfio_t* rf; + reg Sfrsrv_t* rsrv; + reg Void_t* mtx; + + STKMTXLOCK(f1,f2); + + if(f1 && (f1->mode&SF_RDWR) != f1->mode && _sfmode(f1,0,0) < 0) + STKMTXRETURN(f1,f2, NIL(Sfio_t*)); + if(f2 && (f2->mode&SF_RDWR) != f2->mode && _sfmode(f2,0,0) < 0) + STKMTXRETURN(f1,f2, NIL(Sfio_t*)); + if(!f1) + STKMTXRETURN(f1,f2, f2); + + /* give access to other internal functions */ + _Sfstack = sfstack; + + if(f2 == SF_POPSTACK) + { if(!(f2 = f1->push)) + STKMTXRETURN(f1,f2, NIL(Sfio_t*)); + f2->mode &= ~SF_PUSH; + } + else + { if(f2->push) + STKMTXRETURN(f1,f2, NIL(Sfio_t*)); + if(f1->pool && f1->pool != &_Sfpool && f1->pool != f2->pool && + f1 == f1->pool->sf[0]) + { /* get something else to pool front since f1 will be locked */ + for(n = 1; n < f1->pool->n_sf; ++n) + { if(SFFROZEN(f1->pool->sf[n]) ) + continue; + (*_Sfpmove)(f1->pool->sf[n],0); + break; + } + } + } + + if(f2->pool && f2->pool != &_Sfpool && f2 != f2->pool->sf[0]) + (*_Sfpmove)(f2,0); + + /* swap streams */ + sfswap(f1,f2); + + /* but the reserved buffer and mutex must remain the same */ + rsrv = f1->rsrv; f1->rsrv = f2->rsrv; f2->rsrv = rsrv; + mtx = f1->mutex; f1->mutex = f2->mutex; f2->mutex = mtx; + + SFLOCK(f1,0); + SFLOCK(f2,0); + + if(f2->push != f2) + { /* freeze the pushed stream */ + f2->mode |= SF_PUSH; + f1->push = f2; + rf = f1; + } + else + { /* unfreeze the just exposed stream */ + f1->mode &= ~SF_PUSH; + f2->push = NIL(Sfio_t*); + rf = f2; + } + + SFOPEN(f1,0); + SFOPEN(f2,0); + + STKMTXRETURN(f1,f2, rf); +} |