+ ssize_t n, done;
+ size_t lo, mid, hi;
+ int fakeerr = 0;
+ struct badblock *bad, *best;
+ unsigned char *p = buf;
+
+ best = 0; lo = 0; hi = badblocks.n;
+#ifdef DEBUG
+ clear_progress();
+ printf(";; searching badblocks for %"PRIuSEC" .. %"PRIuSEC"\n",
+ pos, pos + want);
+#endif
+ while (lo < hi) {
+ mid = lo + (hi - lo)/2; bad = &badblocks.v[mid];
+#ifdef DEBUG
+ printf(";; try %zu (%"PRIuSEC" .. %"PRIuSEC")... ",
+ mid, bad->start, bad->end);
+#endif
+ if (pos < bad->start) { D( printf("high\n"); ) best = bad; hi = mid; }
+ else if (pos >= bad->end) { D( printf("low\n"); ) lo = mid + 1; }
+ else { D( printf("match!\n"); ) errno = EIO; return (-1); }
+ }
+#ifdef DEBUG
+ if (best)
+ printf(";; next is %"PRIuSEC" .. %"PRIuSEC"\n",
+ best->start, best->end);
+#endif
+ if (best && pos + want > best->start)
+ { want = best->start - pos; fakeerr = EIO; }
+
+ done = 0;
+ while (want) {
+ if (vob)
+ { errno = 0; n = DVDReadBlocks(vob, pos - file->start, want, p); }
+ else if (file) {
+ if (lseek(dvdfd, (off_t)pos*SECTORSZ, SEEK_SET) < 0)
+ bail_syserr(errno, "failed to seek to sector %"PRIuSEC"", pos);
+ errno = 0; n = read(dvdfd, p, want*SECTORSZ);
+ if (n >= 0) n /= SECTORSZ;
+ } else {
+ memset(p, 0, want*SECTORSZ);
+ n = want;
+ }
+
+ if (n > 0) { done += n; pos += n; p += n*SECTORSZ; want -= n; }
+ else if (!n || errno != EINTR) break;
+ }
+ if (fakeerr && !errno) errno = fakeerr;
+ return (!done && errno ? -1 : done);
+}
+
+static ssize_t find_good_sector(secaddr *pos_inout, secaddr end,
+ unsigned char *buf, secaddr sz)
+{
+ int i;
+ secaddr pos = *pos_inout, bad_lo, bad_hi, good, step;