| 1 | /*- |
| 2 | * Copyright (c) 1991 The Regents of the University of California. |
| 3 | * All rights reserved. |
| 4 | * |
| 5 | * Redistribution and use in source and binary forms, with or without |
| 6 | * modification, are permitted provided that the following conditions |
| 7 | * are met: |
| 8 | * 1. Redistributions of source code must retain the above copyright |
| 9 | * notice, this list of conditions and the following disclaimer. |
| 10 | * 2. Redistributions in binary form must reproduce the above copyright |
| 11 | * notice, this list of conditions and the following disclaimer in the |
| 12 | * documentation and/or other materials provided with the distribution. |
| 13 | * 3. All advertising materials mentioning features or use of this software |
| 14 | * must display the following acknowledgement: |
| 15 | * This product includes software developed by the University of |
| 16 | * California, Berkeley and its contributors. |
| 17 | * 4. Neither the name of the University nor the names of its contributors |
| 18 | * may be used to endorse or promote products derived from this software |
| 19 | * without specific prior written permission. |
| 20 | * |
| 21 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
| 22 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| 23 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| 24 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
| 25 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| 26 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| 27 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| 28 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| 29 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| 30 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| 31 | * SUCH DAMAGE. |
| 32 | */ |
| 33 | |
| 34 | #ifndef lint |
| 35 | static char sccsid[] = "@(#)sum2.c 5.1 (Berkeley) 4/4/91"; |
| 36 | #endif /* not lint */ |
| 37 | |
| 38 | #include <sys/types.h> |
| 39 | #include <unistd.h> |
| 40 | |
| 41 | csum2(fd, cval, clen) |
| 42 | register int fd; |
| 43 | u_long *cval, *clen; |
| 44 | { |
| 45 | register u_long crc, total; |
| 46 | register int nr; |
| 47 | register u_char *p; |
| 48 | u_char buf[8192]; |
| 49 | |
| 50 | /* |
| 51 | * Draft 8 POSIX 1003.2: |
| 52 | * |
| 53 | * s = sum of all bytes |
| 54 | * r = s % 2^16 + (s % 2^32) / 2^16 |
| 55 | * crc = (r % 2^16) + r / 2^16 |
| 56 | */ |
| 57 | crc = total = 0; |
| 58 | while ((nr = read(fd, buf, sizeof(buf))) > 0) |
| 59 | for (total += nr, p = buf; nr--; ++p) |
| 60 | crc += *p; |
| 61 | if (nr < 0) |
| 62 | return(1); |
| 63 | |
| 64 | crc = (crc & 0xffff) + (crc >> 16); |
| 65 | crc = (crc & 0xffff) + (crc >> 16); |
| 66 | |
| 67 | *cval = crc; |
| 68 | *clen = total; |
| 69 | return(0); |
| 70 | } |