14887Schin /***********************************************************************
24887Schin * *
34887Schin * This software is part of the ast package *
4*12068SRoger.Faulkner@Oracle.COM * Copyright (c) 1985-2010 AT&T Intellectual Property *
54887Schin * and is licensed under the *
64887Schin * Common Public License, Version 1.0 *
78462SApril.Chin@Sun.COM * by AT&T Intellectual Property *
84887Schin * *
94887Schin * A copy of the License is available at *
104887Schin * http://www.opensource.org/licenses/cpl1.0.txt *
114887Schin * (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9) *
124887Schin * *
134887Schin * Information and Software Systems Research *
144887Schin * AT&T Research *
154887Schin * Florham Park NJ *
164887Schin * *
174887Schin * Glenn Fowler <gsf@research.att.com> *
184887Schin * David Korn <dgk@research.att.com> *
194887Schin * Phong Vo <kpv@research.att.com> *
204887Schin * *
214887Schin ***********************************************************************/
224887Schin #include "sfhdr.h"
234887Schin
244887Schin /* Delete all pending data in the buffer
254887Schin **
264887Schin ** Written by Kiem-Phong Vo.
274887Schin */
284887Schin
294887Schin #if __STD_C
sfpurge(Sfio_t * f)308462SApril.Chin@Sun.COM int sfpurge(Sfio_t* f)
314887Schin #else
324887Schin int sfpurge(f)
338462SApril.Chin@Sun.COM Sfio_t* f;
344887Schin #endif
354887Schin {
364887Schin reg int mode;
378462SApril.Chin@Sun.COM SFMTXDECL(f);
384887Schin
398462SApril.Chin@Sun.COM SFMTXENTER(f,-1);
404887Schin
414887Schin if((mode = f->mode&SF_RDWR) != (int)f->mode && _sfmode(f,mode|SF_SYNCED,0) < 0)
424887Schin SFMTXRETURN(f, -1);
434887Schin
444887Schin if((f->flags&SF_IOCHECK) && f->disc && f->disc->exceptf)
454887Schin (void)(*f->disc->exceptf)(f,SF_PURGE,(Void_t*)((int)1),f->disc);
464887Schin
474887Schin if(f->disc == _Sfudisc)
484887Schin (void)sfclose((*_Sfstack)(f,NIL(Sfio_t*)));
494887Schin
504887Schin /* cannot purge read string streams */
514887Schin if((f->flags&SF_STRING) && (f->mode&SF_READ) )
524887Schin goto done;
534887Schin
544887Schin SFLOCK(f,0);
554887Schin
564887Schin /* if memory map must be a read stream, pretend data is gone */
574887Schin #ifdef MAP_TYPE
584887Schin if(f->bits&SF_MMAP)
594887Schin { f->here -= f->endb - f->next;
604887Schin if(f->data)
614887Schin { SFMUNMAP(f,f->data,f->endb-f->data);
6210898Sroland.mainz@nrubsig.org (void)SFSK(f,f->here,SEEK_SET,f->disc);
634887Schin }
644887Schin SFOPEN(f,0);
654887Schin SFMTXRETURN(f, 0);
664887Schin }
674887Schin #endif
684887Schin
694887Schin switch(f->mode&~SF_LOCK)
704887Schin {
714887Schin default :
724887Schin SFOPEN(f,0);
734887Schin SFMTXRETURN(f, -1);
744887Schin case SF_WRITE :
754887Schin f->next = f->data;
764887Schin if(!f->proc || !(f->flags&SF_READ) || !(f->mode&SF_WRITE) )
774887Schin break;
784887Schin
794887Schin /* 2-way pipe, must clear read buffer */
804887Schin (void)_sfmode(f,SF_READ,1);
814887Schin /* fall through */
824887Schin case SF_READ:
834887Schin if(f->extent >= 0 && f->endb > f->next)
844887Schin { f->here -= f->endb-f->next;
8510898Sroland.mainz@nrubsig.org (void)SFSK(f,f->here,SEEK_SET,f->disc);
864887Schin }
874887Schin f->endb = f->next = f->data;
884887Schin break;
894887Schin }
904887Schin
914887Schin SFOPEN(f,0);
924887Schin
934887Schin done:
944887Schin if((f->flags&SF_IOCHECK) && f->disc && f->disc->exceptf)
954887Schin (void)(*f->disc->exceptf)(f,SF_PURGE,(Void_t*)((int)0),f->disc);
964887Schin
974887Schin SFMTXRETURN(f, 0);
984887Schin }
99