da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin/***********************************************************************
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin* *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin* This software is part of the ast package *
3e14f97f673e8a630f076077de35afdd43dc1587Roger A. Faulkner* Copyright (c) 1985-2010 AT&T Intellectual Property *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin* and is licensed under the *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin* Common Public License, Version 1.0 *
7c2fbfb345896881c631598ee3852ce9ce33fb07April Chin* by AT&T Intellectual Property *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin* *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin* A copy of the License is available at *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin* http://www.opensource.org/licenses/cpl1.0.txt *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin* (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9) *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin* *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin* Information and Software Systems Research *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin* AT&T Research *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin* Florham Park NJ *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin* *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin* Glenn Fowler <gsf@research.att.com> *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin* David Korn <dgk@research.att.com> *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin* Phong Vo <kpv@research.att.com> *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin* *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin***********************************************************************/
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin#include "sfhdr.h"
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin/* Fill the buffer of a stream with data.
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin** If n < 0, sffilbuf() attempts to fill the buffer if it's empty.
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin** If n == 0, if the buffer is not empty, just return the first byte;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin** otherwise fill the buffer and return the first byte.
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin** If n > 0, even if the buffer is not empty, try a read to get as
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin** close to n as possible. n is reset to -1 if stack pops.
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin**
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin** Written by Kiem-Phong Vo
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin*/
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin#if __STD_C
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chinint _sffilbuf(Sfio_t* f, reg int n)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin#else
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chinint _sffilbuf(f,n)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chinSfio_t* f; /* fill the read buffer of this stream */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chinreg int n; /* see above */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin#endif
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin{
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin reg ssize_t r;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin reg int first, local, rcrv, rc, justseek;
7c2fbfb345896881c631598ee3852ce9ce33fb07April Chin SFMTXDECL(f);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin
7c2fbfb345896881c631598ee3852ce9ce33fb07April Chin SFMTXENTER(f,-1);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin GETLOCAL(f,local);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin /* any peek data must be preserved across stacked streams */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin rcrv = f->mode&(SF_RC|SF_RV|SF_LOCK);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin rc = f->getr;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin justseek = f->bits&SF_JUSTSEEK; f->bits &= ~SF_JUSTSEEK;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin for(first = 1;; first = 0, (f->mode &= ~SF_LOCK) )
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin { /* check mode */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin if(SFMODE(f,local) != SF_READ && _sfmode(f,SF_READ,local) < 0)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin SFMTXRETURN(f,-1);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin SFLOCK(f,local);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin /* current extent of available data */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin if((r = f->endb-f->next) > 0)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin { /* on first iteration, n is amount beyond current buffer;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin afterward, n is the exact amount requested */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin if((first && n <= 0) || (!first && n <= r) ||
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin (f->flags&SF_STRING))
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin break;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin /* try shifting left to make room for new data */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin if(!(f->bits&SF_MMAP) && f->next > f->data &&
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin n > (f->size - (f->endb-f->data)) )
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin { ssize_t s = r;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin /* try to maintain block alignment */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin if(f->blksz > 0 && (f->here%f->blksz) == 0 )
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin { s = ((r + f->blksz-1)/f->blksz)*f->blksz;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin if(s+n > f->size)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin s = r;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin }
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin memcpy(f->data, f->endb-s, s);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin f->next = f->data + (s-r);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin f->endb = f->data + s;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin }
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin }
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin else if(!(f->flags&SF_STRING) && !(f->bits&SF_MMAP) )
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin f->next = f->endb = f->endr = f->data;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin if(f->bits&SF_MMAP)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin r = n > 0 ? n : f->size;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin else if(!(f->flags&SF_STRING) )
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin { r = f->size - (f->endb - f->data); /* available buffer */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin if(n > 0)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin { if(r > n && f->extent < 0 && (f->flags&SF_SHARE) )
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin r = n; /* read only as much as requested */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin else if(justseek && n <= f->iosz && f->iosz <= f->size)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin r = f->iosz; /* limit buffer filling */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin }
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin }
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin /* SFRD takes care of discipline read and stack popping */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin f->mode |= rcrv;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin f->getr = rc;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin if((r = SFRD(f,f->endb,r,f->disc)) >= 0)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin { r = f->endb - f->next;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin break;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin }
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin }
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin SFOPEN(f,local);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin rcrv = (n == 0) ? (r > 0 ? (int)(*f->next++) : EOF) : (int)r;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin SFMTXRETURN(f,rcrv);
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin}