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/*
Copyright (C) Andrew Tridgell 1996
Copyright (C) Paul Mackerras 1996
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include "rsync.h"
int csum_length=2; /* initial value */
#define CSUM_CHUNK 64
int checksum_seed = 0;
extern int remote_version;
/*
a simple 32 bit checksum that can be upadted from either end
(inspired by Mark Adler's Adler-32 checksum)
*/
uint32 get_checksum1(char *buf1,int len)
{
int i;
uint32 s1, s2;
signed char *buf = (signed char *)buf1;
s1 = s2 = 0;
for (i = 0; i < (len-4); i+=4) {
s2 += 4*(s1 + buf[i]) + 3*buf[i+1] + 2*buf[i+2] + buf[i+3] +
10*CHAR_OFFSET;
s1 += (buf[i+0] + buf[i+1] + buf[i+2] + buf[i+3] + 4*CHAR_OFFSET);
}
for (; i < len; i++) {
s1 += (buf[i]+CHAR_OFFSET); s2 += s1;
}
return (s1 & 0xffff) + (s2 << 16);
}
static void sum_put(MDstruct *md,char *sum)
{
SIVAL(sum,0,md->buffer[0]);
if (csum_length <= 4) return;
SIVAL(sum,4,md->buffer[1]);
if (csum_length <= 8) return;
SIVAL(sum,8,md->buffer[2]);
if (csum_length <= 12) return;
SIVAL(sum,12,md->buffer[3]);
}
void get_checksum2(char *buf,int len,char *sum)
{
int i;
MDstruct MD;
static char *buf1;
static int len1;
if (len > len1) {
if (buf1) free(buf1);
buf1 = (char *)malloc(len+4);
len1 = len;
if (!buf1) out_of_memory("get_checksum2");
}
MDbegin(&MD);
bcopy(buf,buf1,len);
if (checksum_seed) {
SIVAL(buf1,len,checksum_seed);
len += 4;
}
for(i = 0; i + CSUM_CHUNK <= len; i += CSUM_CHUNK) {
MDupdate(&MD, buf1+i, CSUM_CHUNK*8);
}
if (len - i > 0)
MDupdate(&MD, buf1+i, (len-i)*8);
sum_put(&MD,sum);
}
void file_checksum(char *fname,char *sum,off_t size)
{
off_t i;
MDstruct MD;
struct map_struct *buf;
int fd;
off_t len = size;
char tmpchunk[CSUM_CHUNK];
bzero(sum,csum_length);
fd = open(fname,O_RDONLY);
if (fd == -1) return;
buf = map_file(fd,size);
MDbegin(&MD);
for(i = 0; i + CSUM_CHUNK <= len; i += CSUM_CHUNK) {
bcopy(map_ptr(buf,i,CSUM_CHUNK),tmpchunk,CSUM_CHUNK);
MDupdate(&MD, tmpchunk, CSUM_CHUNK*8);
}
if (len - i > 0) {
bcopy(map_ptr(buf,i,len-i),tmpchunk,len-i);
MDupdate(&MD, tmpchunk, (len-i)*8);
}
sum_put(&MD,sum);
close(fd);
unmap_file(buf);
}
void checksum_init(void)
{
if (remote_version >= 14)
csum_length = 2; /* adaptive */
else
csum_length = SUM_LENGTH;
}
static MDstruct sumMD;
static int sumresidue;
static char sumrbuf[CSUM_CHUNK];
void sum_init(void)
{
char s[4];
MDbegin(&sumMD);
sumresidue=0;
SIVAL(s,0,checksum_seed);
sum_update(s,4);
}
void sum_update(char *p,int len)
{
int i;
if (len + sumresidue < CSUM_CHUNK) {
bcopy(p,sumrbuf+sumresidue,len);
sumresidue += len;
return;
}
if (sumresidue) {
i = MIN(CSUM_CHUNK-sumresidue,len);
bcopy(p,sumrbuf+sumresidue,i);
MDupdate(&sumMD, sumrbuf, (i+sumresidue)*8);
len -= i;
p += i;
}
for(i = 0; i + CSUM_CHUNK <= len; i += CSUM_CHUNK) {
bcopy(p+i,sumrbuf,CSUM_CHUNK);
MDupdate(&sumMD, sumrbuf, CSUM_CHUNK*8);
}
if (len - i > 0) {
sumresidue = len-i;
bcopy(p+i,sumrbuf,sumresidue);
} else {
sumresidue = 0;
}
}
void sum_end(char *sum)
{
if (sumresidue)
MDupdate(&sumMD, sumrbuf, sumresidue*8);
SIVAL(sum,0,sumMD.buffer[0]);
SIVAL(sum,4,sumMD.buffer[1]);
SIVAL(sum,8,sumMD.buffer[2]);
SIVAL(sum,12,sumMD.buffer[3]);
}
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