diff options
Diffstat (limited to 'usr/src/lib/libast/common/sfio/sfpurge.c')
| -rw-r--r-- | usr/src/lib/libast/common/sfio/sfpurge.c | 97 |
1 files changed, 97 insertions, 0 deletions
diff --git a/usr/src/lib/libast/common/sfio/sfpurge.c b/usr/src/lib/libast/common/sfio/sfpurge.c new file mode 100644 index 0000000000..4c1716bcee --- /dev/null +++ b/usr/src/lib/libast/common/sfio/sfpurge.c @@ -0,0 +1,97 @@ +/*********************************************************************** +* * +* 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" + +/* Delete all pending data in the buffer +** +** Written by Kiem-Phong Vo. +*/ + +#if __STD_C +int sfpurge(reg Sfio_t* f) +#else +int sfpurge(f) +reg Sfio_t* f; +#endif +{ + reg int mode; + + SFMTXSTART(f,-1); + + if((mode = f->mode&SF_RDWR) != (int)f->mode && _sfmode(f,mode|SF_SYNCED,0) < 0) + SFMTXRETURN(f, -1); + + if((f->flags&SF_IOCHECK) && f->disc && f->disc->exceptf) + (void)(*f->disc->exceptf)(f,SF_PURGE,(Void_t*)((int)1),f->disc); + + if(f->disc == _Sfudisc) + (void)sfclose((*_Sfstack)(f,NIL(Sfio_t*))); + + /* cannot purge read string streams */ + if((f->flags&SF_STRING) && (f->mode&SF_READ) ) + goto done; + + SFLOCK(f,0); + + /* if memory map must be a read stream, pretend data is gone */ +#ifdef MAP_TYPE + if(f->bits&SF_MMAP) + { f->here -= f->endb - f->next; + if(f->data) + { SFMUNMAP(f,f->data,f->endb-f->data); + SFSK(f,f->here,SEEK_SET,f->disc); + } + SFOPEN(f,0); + SFMTXRETURN(f, 0); + } +#endif + + switch(f->mode&~SF_LOCK) + { + default : + SFOPEN(f,0); + SFMTXRETURN(f, -1); + case SF_WRITE : + f->next = f->data; + if(!f->proc || !(f->flags&SF_READ) || !(f->mode&SF_WRITE) ) + break; + + /* 2-way pipe, must clear read buffer */ + (void)_sfmode(f,SF_READ,1); + /* fall through */ + case SF_READ: + if(f->extent >= 0 && f->endb > f->next) + { f->here -= f->endb-f->next; + SFSK(f,f->here,SEEK_SET,f->disc); + } + f->endb = f->next = f->data; + break; + } + + SFOPEN(f,0); + +done: + if((f->flags&SF_IOCHECK) && f->disc && f->disc->exceptf) + (void)(*f->disc->exceptf)(f,SF_PURGE,(Void_t*)((int)0),f->disc); + + SFMTXRETURN(f, 0); +} |