+ OFF_T i;
+ struct map_struct *buf;
+ int fd;
+ OFF_T len = size;
+ char tmpchunk[CSUM_CHUNK];
+ struct mdfour m;
+
+ memset(sum,0,MD4_SUM_LENGTH);
+
+ fd = do_open(fname, O_RDONLY, 0);
+ if (fd == -1) return;
+
+ buf = map_file(fd,size);
+
+ mdfour_begin(&m);
+
+ for(i = 0; i + CSUM_CHUNK <= len; i += CSUM_CHUNK) {
+ memcpy(tmpchunk, map_ptr(buf,i,CSUM_CHUNK), CSUM_CHUNK);
+ mdfour_update(&m, (uchar *)tmpchunk, CSUM_CHUNK);
+ }
+
+ if (len - i > 0) {
+ memcpy(tmpchunk, map_ptr(buf,i,len-i), len-i);
+ mdfour_update(&m, (uchar *)tmpchunk, (len-i));
+ }
+
+ mdfour_result(&m, (uchar *)sum);
+
+ close(fd);
+ unmap_file(buf);
+}
+
+
+void checksum_init(void)
+{
+ if (remote_version >= 14)
+ csum_length = 2; /* adaptive */
+ else
+ csum_length = SUM_LENGTH;
+}
+
+
+
+static int sumresidue;
+static char sumrbuf[CSUM_CHUNK];
+static struct mdfour md;
+
+void sum_init(void)
+{
+ char s[4];
+ mdfour_begin(&md);
+ 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) {
+ memcpy(sumrbuf+sumresidue, p, len);
+ sumresidue += len;
+ return;
+ }
+
+ if (sumresidue) {
+ i = MIN(CSUM_CHUNK-sumresidue,len);
+ memcpy(sumrbuf+sumresidue,p,i);
+ mdfour_update(&md, (uchar *)sumrbuf, (i+sumresidue));
+ len -= i;
+ p += i;
+ }
+
+ for(i = 0; i + CSUM_CHUNK <= len; i += CSUM_CHUNK) {
+ memcpy(sumrbuf,p+i,CSUM_CHUNK);
+ mdfour_update(&md, (uchar *)sumrbuf, CSUM_CHUNK);
+ }
+
+ if (len - i > 0) {
+ sumresidue = len-i;
+ memcpy(sumrbuf,p+i,sumresidue);
+ } else {
+ sumresidue = 0;
+ }
+}
+
+void sum_end(char *sum)
+{
+ if (sumresidue) {
+ mdfour_update(&md, (uchar *)sumrbuf, sumresidue);
+ }
+
+ mdfour_result(&md, (uchar *)sum);