#include "sfhdr.h"
#if __STD_C
Sfdisc_t* sfdisc(reg Sfio_t* f, reg Sfdisc_t* disc)
#else
Sfdisc_t* sfdisc(f,disc)
reg Sfio_t* f;
reg Sfdisc_t* disc;
#endif
{
reg Sfdisc_t *d, *rdisc;
reg Sfread_f oreadf;
reg Sfwrite_f owritef;
reg Sfseek_f oseekf;
ssize_t n;
SFMTXSTART(f, NIL(Sfdisc_t*));
if((f->flags&SF_READ) && f->proc && (f->mode&SF_WRITE) )
{
if(_sfmode(f,SF_READ,0) < 0)
SFMTXRETURN(f, NIL(Sfdisc_t*));
}
else if((f->mode&SF_RDWR) != f->mode && _sfmode(f,0,0) < 0)
SFMTXRETURN(f, NIL(Sfdisc_t*));
SFLOCK(f,0);
rdisc = NIL(Sfdisc_t*);
if(!(f->flags&SF_STRING))
{ if(((f->mode&SF_WRITE) && f->next > f->data) ||
(f->mode&SF_READ) || f->disc == _Sfudisc )
(void)SFSYNC(f);
if(((f->mode&SF_WRITE) && (n = f->next-f->data) > 0) ||
((f->mode&SF_READ) && f->extent < 0 && (n = f->endb-f->next) > 0) )
{
reg Sfexcept_f exceptf;
reg int rv = 0;
exceptf = disc ? disc->exceptf :
f->disc ? f->disc->exceptf : NIL(Sfexcept_f);
if(exceptf)
{ SFOPEN(f,0);
rv = (*exceptf)(f,SF_DBUFFER,&n, disc ? disc : f->disc);
SFLOCK(f,0);
}
if(rv <= 0)
goto done;
}
}
#define GETDISCF(func,iof,type) \
{ for(d = f->disc; d && !d->iof; d = d->disc) ; \
func = d ? d->iof : NIL(type); \
}
GETDISCF(oreadf,readf,Sfread_f);
GETDISCF(owritef,writef,Sfwrite_f);
GETDISCF(oseekf,seekf,Sfseek_f);
if(disc == SF_POPDISC)
{
if(!(d = f->disc) )
goto done;
disc = d->disc;
if(d->exceptf)
{ SFOPEN(f,0);
if((*(d->exceptf))(f,SF_DPOP,(Void_t*)disc,d) < 0 )
goto done;
SFLOCK(f,0);
}
f->disc = disc;
rdisc = d;
}
else
{
do
{
d = f->disc;
if(d && d->exceptf)
{ SFOPEN(f,0);
if( (*(d->exceptf))(f,SF_DPUSH,(Void_t*)disc,d) < 0 )
goto done;
SFLOCK(f,0);
}
} while(d != f->disc);
for(; d; d = d->disc)
if(d == disc)
goto done;
disc->disc = f->disc;
f->disc = disc;
rdisc = disc;
}
if(!(f->flags&SF_STRING) )
{
reg int reinit = 0;
#define DISCF(dst,iof,type) (dst ? dst->iof : NIL(type))
#define REINIT(oiof,iof,type) \
if(!reinit) \
{ for(d = f->disc; d && !d->iof; d = d->disc) ; \
if(DISCF(d,iof,type) != oiof) \
reinit = 1; \
}
REINIT(oreadf,readf,Sfread_f);
REINIT(owritef,writef,Sfwrite_f);
REINIT(oseekf,seekf,Sfseek_f);
if(reinit)
{ SETLOCAL(f);
f->bits &= ~SF_NULL;
if((f->bits&SF_MMAP) || (f->mode&SF_INIT))
sfsetbuf(f,NIL(Void_t*),(size_t)SF_UNBOUND);
else if(f->data == f->tiny)
sfsetbuf(f,NIL(Void_t*),0);
else
{ int flags = f->flags;
sfsetbuf(f,(Void_t*)f->data,f->size);
f->flags |= (flags&SF_MALLOC);
}
}
}
done :
SFOPEN(f,0);
SFMTXRETURN(f, rdisc);
}