diff options
| -rw-r--r-- | diffcore-rename.c | 40 |
1 files changed, 21 insertions, 19 deletions
diff --git a/diffcore-rename.c b/diffcore-rename.c index 6dd753bc6..e21a8071b 100644 --- a/diffcore-rename.c +++ b/diffcore-rename.c @@ -68,37 +68,39 @@ static int estimate_similarity(struct diff_filespec *src, * else. */ void *delta; - unsigned long delta_size; + unsigned long delta_size, base_size; int score; delta_size = ((src->size < dst->size) ? (dst->size - src->size) : (src->size - dst->size)); - - /* We would not consider rename followed by more than - * minimum_score/MAX_SCORE edits; that is, delta_size must be smaller - * than (src->size + dst->size)/2 * minimum_score/MAX_SCORE, - * which means... + base_size = ((src->size < dst->size) ? src->size : dst->size); + + /* We would not consider edits that change the file size so + * drastically. delta_size must be smaller than + * minimum_score/MAX_SCORE * min(src->size, dst->size). + * Note that base_size == 0 case is handled here already + * and the final score computation below would not have a + * divide-by-zero issue. */ - - if ((src->size+dst->size)*minimum_score < delta_size*MAX_SCORE*2) + if (base_size * minimum_score < delta_size * MAX_SCORE) return 0; delta = diff_delta(src->data, src->size, dst->data, dst->size, &delta_size); + /* + * We currently punt here, but we may later end up parsing the + * delta to really assess the extent of damage. A big consecutive + * remove would produce small delta_size that affects quite a + * big portion of the file. + */ free(delta); - /* This "delta" is really xdiff with adler32 and all the - * overheads but it is a quick and dirty approximation. - * - * Now we will give some score to it. 100% edit gets - * 0 points and 0% edit gets MAX_SCORE points. That is, every - * 1/MAX_SCORE edit gets 1 point penalty. The amount of penalty is: - * - * (delta_size * 2 / (src->size + dst->size)) * MAX_SCORE - * + /* + * Now we will give some score to it. 100% edit gets 0 points + * and 0% edit gets MAX_SCORE points. */ - score = MAX_SCORE-(MAX_SCORE*2*delta_size/(src->size+dst->size)); + score = MAX_SCORE - (MAX_SCORE * delta_size / base_size); if (score < 0) return 0; if (MAX_SCORE < score) return MAX_SCORE; return score; @@ -314,7 +316,7 @@ void diff_detect_rename(struct diff_queue_struct *q, if (mx[i].dst->xfrm_flags & RENAME_DST_MATCHED) continue; /* alreayd done, either exact or fuzzy. */ if (mx[i].score < minimum_score) - continue; + break; /* there is not any more diffs applicable. */ record_rename_pair(&outq, mx[i].src, mx[i].dst, mx[i].rank, mx[i].score); |