2 Copyright (C) Andrew Tridgell 1996
3 Copyright (C) Paul Mackerras 1996
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.
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.
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.
22 int csum_length=2; /* initial value */
26 int checksum_seed = 0;
27 extern int remote_version;
30 a simple 32 bit checksum that can be upadted from either end
31 (inspired by Mark Adler's Adler-32 checksum)
33 uint32 get_checksum1(char *buf1,int len)
37 schar *buf = (schar *)buf1;
40 for (i = 0; i < (len-4); i+=4) {
41 s2 += 4*(s1 + buf[i]) + 3*buf[i+1] + 2*buf[i+2] + buf[i+3] +
43 s1 += (buf[i+0] + buf[i+1] + buf[i+2] + buf[i+3] + 4*CHAR_OFFSET);
45 for (; i < len; i++) {
46 s1 += (buf[i]+CHAR_OFFSET); s2 += s1;
48 return (s1 & 0xffff) + (s2 << 16);
52 static void sum_put(MDstruct *md,char *sum)
54 SIVAL(sum,0,md->buffer[0]);
55 if (csum_length <= 4) return;
56 SIVAL(sum,4,md->buffer[1]);
57 if (csum_length <= 8) return;
58 SIVAL(sum,8,md->buffer[2]);
59 if (csum_length <= 12) return;
60 SIVAL(sum,12,md->buffer[3]);
64 void get_checksum2(char *buf,int len,char *sum)
73 buf1 = (char *)malloc(len+4);
75 if (!buf1) out_of_memory("get_checksum2");
82 SIVAL(buf1,len,checksum_seed);
86 for(i = 0; i + CSUM_CHUNK <= len; i += CSUM_CHUNK) {
87 MDupdate(&MD, buf1+i, CSUM_CHUNK*8);
90 MDupdate(&MD, buf1+i, (len-i)*8);
96 void file_checksum(char *fname,char *sum,OFF_T size)
100 struct map_struct *buf;
103 char tmpchunk[CSUM_CHUNK];
105 bzero(sum,csum_length);
107 fd = open(fname,O_RDONLY);
108 if (fd == -1) return;
110 buf = map_file(fd,size);
114 for(i = 0; i + CSUM_CHUNK <= len; i += CSUM_CHUNK) {
115 bcopy(map_ptr(buf,i,CSUM_CHUNK),tmpchunk,CSUM_CHUNK);
116 MDupdate(&MD, tmpchunk, CSUM_CHUNK*8);
120 bcopy(map_ptr(buf,i,len-i),tmpchunk,len-i);
121 MDupdate(&MD, tmpchunk, (len-i)*8);
131 void checksum_init(void)
133 if (remote_version >= 14)
134 csum_length = 2; /* adaptive */
136 csum_length = SUM_LENGTH;
141 static MDstruct sumMD;
142 static int sumresidue;
143 static char sumrbuf[CSUM_CHUNK];
150 SIVAL(s,0,checksum_seed);
154 void sum_update(char *p,int len)
157 if (len + sumresidue < CSUM_CHUNK) {
158 bcopy(p,sumrbuf+sumresidue,len);
164 i = MIN(CSUM_CHUNK-sumresidue,len);
165 bcopy(p,sumrbuf+sumresidue,i);
166 MDupdate(&sumMD, sumrbuf, (i+sumresidue)*8);
171 for(i = 0; i + CSUM_CHUNK <= len; i += CSUM_CHUNK) {
172 bcopy(p+i,sumrbuf,CSUM_CHUNK);
173 MDupdate(&sumMD, sumrbuf, CSUM_CHUNK*8);
178 bcopy(p+i,sumrbuf,sumresidue);
184 void sum_end(char *sum)
187 MDupdate(&sumMD, sumrbuf, sumresidue*8);
189 SIVAL(sum,0,sumMD.buffer[0]);
190 SIVAL(sum,4,sumMD.buffer[1]);
191 SIVAL(sum,8,sumMD.buffer[2]);
192 SIVAL(sum,12,sumMD.buffer[3]);