usr/src/lib/libc/stdio/fread.c

/*
 * Copyright (c) 1980 Regents of the University of California.
 * All rights reserved.  The Berkeley software License Agreement
 * specifies the terms and conditions for redistribution.
 */

#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)fread.c     5.2 (Berkeley) %G%";
#endif LIBC_SCCS and not lint

#include        <stdio.h>

fread(ptr, size, count, iop)
        register char *ptr;
        unsigned size, count;
        register FILE *iop;
{
        register int s;
        int c;

        s = size * count;
        while (s > 0) {
                if (iop->_cnt < s) {
                        if (iop->_cnt > 0) {
                                bcopy(iop->_ptr, ptr, iop->_cnt);
                                ptr += iop->_cnt;
                                s -= iop->_cnt;
                        }
                        /*
                         * filbuf clobbers _cnt & _ptr,
                         * so don't waste time setting them.
                         */
                        if ((c = _filbuf(iop)) == EOF)
                                break;
                        *ptr++ = c;
                        s--;
                }
                if (iop->_cnt >= s) {
                        bcopy(iop->_ptr, ptr, s);
                        iop->_ptr += s;
                        iop->_cnt -= s;
                        return (count);
                }
        }
        return (size != 0 ? count - ((s + size - 1) / size) : 0);
}