| 1 | /* |
| 2 | Copyright (C) Andrew Tridgell 1996 |
| 3 | Copyright (C) Paul Mackerras 1996 |
| 4 | |
| 5 | This program is free software; you can redistribute it and/or modify |
| 6 | it under the terms of the GNU General Public License as published by |
| 7 | the Free Software Foundation; either version 2 of the License, or |
| 8 | (at your option) any later version. |
| 9 | |
| 10 | This program is distributed in the hope that it will be useful, |
| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 13 | GNU General Public License for more details. |
| 14 | |
| 15 | You should have received a copy of the GNU General Public License |
| 16 | along with this program; if not, write to the Free Software |
| 17 | Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
| 18 | */ |
| 19 | |
| 20 | #include "rsync.h" |
| 21 | |
| 22 | extern int csum_length; |
| 23 | |
| 24 | /* |
| 25 | a simple 32 bit checksum that can be upadted from either end |
| 26 | (inspired by Mark Adler's Adler-32 checksum) |
| 27 | */ |
| 28 | uint32 get_checksum1(char *buf,int len) |
| 29 | { |
| 30 | int i; |
| 31 | uint32 s1, s2; |
| 32 | |
| 33 | s1 = s2 = 0; |
| 34 | for (i = 0; i < len; i++) { |
| 35 | s1 += buf[i]; |
| 36 | s2 += s1; |
| 37 | } |
| 38 | return (s1 & 0xffff) + (s2 << 16); |
| 39 | } |
| 40 | |
| 41 | |
| 42 | void get_checksum2(char *buf,int len,char *sum) |
| 43 | { |
| 44 | char buf2[64]; |
| 45 | int i; |
| 46 | MDstruct MD; |
| 47 | |
| 48 | MDbegin(&MD); |
| 49 | for(i = 0; i + 64 <= len; i += 64) { |
| 50 | bcopy(buf+i,buf2,64); |
| 51 | MDupdate(&MD, buf2, 512); |
| 52 | } |
| 53 | bcopy(buf+i,buf2,len-i); |
| 54 | MDupdate(&MD, buf2, (len-i)*8); |
| 55 | SIVAL(sum,0,MD.buffer[0]); |
| 56 | if (csum_length <= 4) return; |
| 57 | SIVAL(sum,4,MD.buffer[1]); |
| 58 | if (csum_length <= 8) return; |
| 59 | SIVAL(sum,8,MD.buffer[2]); |
| 60 | if (csum_length <= 12) return; |
| 61 | SIVAL(sum,12,MD.buffer[3]); |
| 62 | } |
| 63 | |
| 64 | void file_checksum(char *fname,char *sum,off_t size) |
| 65 | { |
| 66 | char *buf; |
| 67 | int fd; |
| 68 | bzero(sum,csum_length); |
| 69 | |
| 70 | fd = open(fname,O_RDONLY); |
| 71 | if (fd == -1) return; |
| 72 | |
| 73 | buf = map_file(fd,size); |
| 74 | if (!buf) { |
| 75 | close(fd); |
| 76 | return; |
| 77 | } |
| 78 | |
| 79 | get_checksum2(buf,size,sum); |
| 80 | close(fd); |
| 81 | unmap_file(buf,size); |
| 82 | } |