diff options
Diffstat (limited to 'file_cmds/cksum/sum2.c')
| -rw-r--r-- | file_cmds/cksum/sum2.c | 79 |
1 files changed, 79 insertions, 0 deletions
diff --git a/file_cmds/cksum/sum2.c b/file_cmds/cksum/sum2.c new file mode 100644 index 0000000..126b428 --- /dev/null +++ b/file_cmds/cksum/sum2.c @@ -0,0 +1,79 @@ +/*- + * Copyright (c) 1991, 1993 + * The Regents of the University of California. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. All advertising materials mentioning features or use of this software + * must display the following acknowledgement: + * This product includes software developed by the University of + * California, Berkeley and its contributors. + * 4. Neither the name of the University nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#ifndef lint +#if 0 +static char sccsid[] = "@(#)sum2.c 8.1 (Berkeley) 6/6/93"; +#endif +#endif /* not lint */ +#include <sys/cdefs.h> +__FBSDID("$FreeBSD: src/usr.bin/cksum/sum2.c,v 1.8 2003/03/13 23:32:28 robert Exp $"); + +#include <sys/types.h> + +#include <unistd.h> +#include <stdint.h> + +#include "extern.h" + +int +csum2(int fd, uint32_t *cval, off_t *clen) +{ + uint32_t lcrc; + ssize_t nr; + off_t total; + u_char *p; + u_char buf[8192]; + + /* + * Draft 8 POSIX 1003.2: + * + * s = sum of all bytes + * r = s % 2^16 + (s % 2^32) / 2^16 + * lcrc = (r % 2^16) + r / 2^16 + */ + lcrc = 0; + total = 0; + while ((nr = read(fd, buf, sizeof(buf))) > 0) + for (total += nr, p = buf; nr--; ++p) + lcrc += *p; + if (nr < 0) + return (1); + + lcrc = (lcrc & 0xffff) + (lcrc >> 16); + lcrc = (lcrc & 0xffff) + (lcrc >> 16); + + *cval = lcrc; + *clen = total; + return (0); +} |