#include "sfhdr.h"
#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,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*)));
if((f->flags&SF_STRING) && (f->mode&SF_READ) )
goto done;
SFLOCK(f,0);
#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;
(void)_sfmode(f,SF_READ,1);
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);
}