sfread.c revision da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin/***********************************************************************
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin* This software is part of the ast package *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin* Copyright (c) 1985-2007 AT&T Knowledge Ventures *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin* and is licensed under the *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin* Common Public License, Version 1.0 *
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin* by AT&T Knowledge Ventures *
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/* Read n bytes from a stream into a buffer
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin** Written by Kiem-Phong Vo.
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chinssize_t sfread(reg Sfio_t* f, Void_t* buf, reg size_t n)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin justseek = f->bits&SF_JUSTSEEK; f->bits &= ~SF_JUSTSEEK;
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin /* release peek lock */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin { /* actually read the data now */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin { /* check stream mode */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin if(SFMODE(f,local) != SF_READ && _sfmode(f,SF_READ,local) < 0)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin if((r = f->endb - f->next) > 0) /* has buffered data */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin { if(r > (ssize_t)n)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin if(s != f->next)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin if(n <= 0) /* all done */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin /* exact IO is desirable for these cases */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin else if(justseek && n <= f->iosz && f->iosz <= f->size)
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin /* if read almost full size, then just do it direct */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin /* read directly to user's buffer */
da2e3ebdc1edfbc5028edf1354e7dd2fa69a7968chin if(r == 0 || n == 0) /* eof or eob */