diff options
Diffstat (limited to 'usr.bin/cksum/sum2.c')
| -rw-r--r-- | usr.bin/cksum/sum2.c | 71 |
1 files changed, 71 insertions, 0 deletions
diff --git a/usr.bin/cksum/sum2.c b/usr.bin/cksum/sum2.c new file mode 100644 index 0000000..c54d88e --- /dev/null +++ b/usr.bin/cksum/sum2.c @@ -0,0 +1,71 @@ +/*- + * 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 +static char sccsid[] = "@(#)sum2.c 8.1 (Berkeley) 6/6/93"; +#endif /* not lint */ + +#include <sys/types.h> +#include <unistd.h> + +int +csum2(fd, cval, clen) + register int fd; + u_long *cval, *clen; +{ + register u_long crc, total; + register int nr; + register 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 + * crc = (r % 2^16) + r / 2^16 + */ + crc = total = 0; + while ((nr = read(fd, buf, sizeof(buf))) > 0) + for (total += nr, p = buf; nr--; ++p) + crc += *p; + if (nr < 0) + return(1); + + crc = (crc & 0xffff) + (crc >> 16); + crc = (crc & 0xffff) + (crc >> 16); + + *cval = crc; + *clen = total; + return(0); +} |
