#include "sfhdr.h"
#if __STD_C
int _sffilbuf(Sfio_t* f, reg int n)
#else
int _sffilbuf(f,n)
Sfio_t* f;
reg int n;
#endif
{
reg ssize_t r;
reg int first, local, rcrv, rc, justseek;
SFMTXSTART(f,-1);
GETLOCAL(f,local);
rcrv = f->mode&(SF_RC|SF_RV|SF_LOCK);
rc = f->getr;
justseek = f->bits&SF_JUSTSEEK; f->bits &= ~SF_JUSTSEEK;
for(first = 1;; first = 0, (f->mode &= ~SF_LOCK) )
{
if(SFMODE(f,local) != SF_READ && _sfmode(f,SF_READ,local) < 0)
SFMTXRETURN(f,-1);
SFLOCK(f,local);
if((r = f->endb-f->next) > 0)
{
if((first && n <= 0) || (!first && n <= r) ||
(f->flags&SF_STRING))
break;
if(!(f->bits&SF_MMAP) && f->next > f->data &&
n > (f->size - (f->endb-f->data)) )
{ memcpy(f->data, f->next, r);
f->next = f->data;
f->endb = f->data + r;
}
}
else if(!(f->flags&SF_STRING) && !(f->bits&SF_MMAP) )
f->next = f->endb = f->endr = f->data;
if(f->bits&SF_MMAP)
r = n > 0 ? n : f->size;
else if(!(f->flags&SF_STRING) )
{ r = f->size - (f->endb - f->data);
if(n > 0)
{ if(r > n && f->extent < 0 && (f->flags&SF_SHARE) )
r = n;
else if(justseek && n <= f->iosz && f->iosz <= f->size)
r = f->iosz;
}
}
f->mode |= rcrv;
f->getr = rc;
if((r = SFRD(f,f->endb,r,f->disc)) >= 0)
{ r = f->endb - f->next;
break;
}
}
SFOPEN(f,local);
rcrv = (n == 0) ? (r > 0 ? (int)(*f->next++) : EOF) : (int)r;
SFMTXRETURN(f,rcrv);
}