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* A copy of the License is available at *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin* (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9) *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin* Information and Software Systems Research *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin* AT&T Research *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin* Florham Park NJ *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin* Glenn Fowler <gsf@research.att.com> *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin* David Korn <dgk@research.att.com> *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin* Phong Vo <kpv@research.att.com> *
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** Written by Kiem-Phong Vo
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin /* any peek data must be preserved across stacked streams */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin justseek = f->bits&SF_JUSTSEEK; f->bits &= ~SF_JUSTSEEK;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin { /* check mode */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin if(SFMODE(f,local) != SF_READ && _sfmode(f,SF_READ,local) < 0)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin /* current extent of available data */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin { /* on first iteration, n is amount beyond current buffer;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin afterward, n is the exact amount requested */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin /* try shifting left to make room for new data */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin /* try to maintain block alignment */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin if(s+n > f->size)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin r = n > 0 ? n : f->size;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin { r = f->size - (f->endb - f->data); /* available buffer */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin r = n; /* read only as much as requested */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin else if(justseek && n <= f->iosz && f->iosz <= f->size)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin /* SFRD takes care of discipline read and stack popping */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin rcrv = (n == 0) ? (r > 0 ? (int)(*f->next++) : EOF) : (int)r;