Sender realigns chunks with generator during an --inplace copy

when sending a sequence of zeros.

diff --git a/match.c b/match.c
index 407387f..cbb6fe2 100644 (file)
--- a/match.c
+++ b/match.c
@@ -237,10 +237,11 @@ static void hash_search(int f,struct sum_struct *s,
                                /* All the generator's chunks start at blength boundaries. */
                                while (aligned_offset < offset)
                                        aligned_offset += s->blength;
                                /* All the generator's chunks start at blength boundaries. */
                                while (aligned_offset < offset)
                                        aligned_offset += s->blength;

-                               if (offset == aligned_offset) {
+                               if (offset == aligned_offset
+                                || (sum == 0 && l == s->blength && aligned_offset + l <= len)) {

                                        int32 i2;
                                        for (i2 = i; i2 >= 0; i2 = s->sums[i2].chain) {
                                        int32 i2;
                                        for (i2 = i; i2 >= 0; i2 = s->sums[i2].chain) {

-                                               if (s->sums[i2].offset != offset)
+                                               if (s->sums[i2].offset != aligned_offset)

                                                        continue;
                                                if (i2 != i) {
                                                        if (sum != s->sums[i2].sum1
                                                        continue;
                                                if (i2 != i) {
                                                        if (sum != s->sums[i2].sum1


@@ -249,9 +250,26 @@ static void hash_search(int f,struct sum_struct *s,
                                                                break;
                                                        i = i2;
                                                }
                                                                break;
                                                        i = i2;
                                                }

+                                               want_i = i;
+                                               if (offset != aligned_offset) {
+                                                       /* We've matched some zeros in a spot that is also zeros
+                                                        * further along in the basis file, if we find zeros ahead
+                                                        * in the sender's file, we'll output enough literal data
+                                                        * to re-align with the basis file, and get back to seeking
+                                                        * instead of writing. */
+                                                       map = (schar *)map_ptr(buf, aligned_offset, l);
+                                                       sum = get_checksum1((char *)map, l);
+                                                       if (sum != s->sums[i2].sum1)
+                                                               break;
+                                                       get_checksum2((char *)map, l, sum2);
+                                                       if (memcmp(sum2, s->sums[i2].sum2, s->s2length) != 0)
+                                                               break;
+                                                       /* OK, we have a re-alignment match.  Bump the offset
+                                                        * forward to the new match point. */
+                                                       offset = aligned_offset;
+                                               }

                                                /* This chunk remained in the same spot in the old and new file. */
                                                s->sums[i].flags |= SUMFLG_SAME_OFFSET;
                                                /* This chunk remained in the same spot in the old and new file. */
                                                s->sums[i].flags |= SUMFLG_SAME_OFFSET;

-                                               want_i = i;

                                                break;
                                        }
                                }
                                                break;
                                        }
                                }