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Annotation of prex-old/usr/lib/libc/stdio/fread.c, Revision 1.1.1.1

1.1       nbrk        1: /*-
                      2:  * Copyright (c) 1990, 1993
                      3:  *     The Regents of the University of California.  All rights reserved.
                      4:  *
                      5:  * This code is derived from software contributed to Berkeley by
                      6:  * Chris Torek.
                      7:  *
                      8:  * Redistribution and use in source and binary forms, with or without
                      9:  * modification, are permitted provided that the following conditions
                     10:  * are met:
                     11:  * 1. Redistributions of source code must retain the above copyright
                     12:  *    notice, this list of conditions and the following disclaimer.
                     13:  * 2. Redistributions in binary form must reproduce the above copyright
                     14:  *    notice, this list of conditions and the following disclaimer in the
                     15:  *    documentation and/or other materials provided with the distribution.
                     16:  * 3. Neither the name of the University nor the names of its contributors
                     17:  *    may be used to endorse or promote products derived from this software
                     18:  *    without specific prior written permission.
                     19:  *
                     20:  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
                     21:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
                     22:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
                     23:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
                     24:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
                     25:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
                     26:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
                     27:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
                     28:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
                     29:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
                     30:  * SUCH DAMAGE.
                     31:  */
                     32:
                     33: #include <stdio.h>
                     34: #include <string.h>
                     35: #include "local.h"
                     36:
                     37: size_t
                     38: fread(buf, size, count, fp)
                     39:        void *buf;
                     40:        size_t size, count;
                     41:        FILE *fp;
                     42: {
                     43:        size_t resid;
                     44:        char *p;
                     45:        int r;
                     46:        size_t total;
                     47:
                     48:        /*
                     49:         * The ANSI standard requires a return value of 0 for a count
                     50:         * or a size of 0.  Peculiarily, it imposes no such requirements
                     51:         * on fwrite; it only requires fread to be broken.
                     52:         */
                     53:        if ((resid = count * size) == 0)
                     54:                return (0);
                     55:        if (fp->_r < 0)
                     56:                fp->_r = 0;
                     57:        total = resid;
                     58:        p = buf;
                     59:        while (resid > (size_t)(r = fp->_r)) {
                     60:                (void)memcpy((void *)p, (void *)fp->_p, (size_t)r);
                     61:                fp->_p += r;
                     62:                /* fp->_r = 0 ... done in __srefill */
                     63:                p += r;
                     64:                resid -= r;
                     65:                if (__srefill(fp)) {
                     66:                        /* no more input: return partial result */
                     67:                        return ((total - resid) / size);
                     68:                }
                     69:        }
                     70:        (void)memcpy((void *)p, (void *)fp->_p, resid);
                     71:        fp->_r -= resid;
                     72:        fp->_p += resid;
                     73:        return (count);
                     74: }