René ScharfeRounding down the printed (dis)similarity index allows us to use "100%" as a special value that indicates complete rewrites and fully equal file contents, respectively.
Signed-off-by: Rene Scharfe <rene.scharfe@lsrfire.ath.cx> ---
The added documentation is only correct if you apply the diffcore-rename patch, too.
Documentation/diff-format.txt | 7 +++++++ diff.c | 30 +++++++++++++++++++----------- 2 files changed, 26 insertions(+), 11 deletions(-)
Show changes to 2 files +26 −11
Documentation/diff-format.txt, diff.c
diff --git a/Documentation/diff-format.txt b/Documentation/diff-format.txt index 18d49d2..0015032 100644 --- a/Documentation/diff-format.txt +++ b/Documentation/diff-format.txt @@ -126,6 +126,13 @@ the file that rename/copy produces, respectively. If there is need for such substitution then the whole pathname is put in double quotes. +The similarity index is the percentage of unchanged lines, and +the dissimilarity index is the percentage of changed lines. It +is a rounded down integer, followed by a percent sign. The +similarity index value of 100% is thus reserved for two equal +files, while 100% dissimilarity means that no line from the old +file made it into the new one. + combined diff format -------------------- diff --git a/diff.c b/diff.c index 4aa9bbc..f1db55d 100644 --- a/diff.c +++ b/diff.c @@ -1813,6 +1813,19 @@ static void diff_fill_sha1_info(struct diff_filespec *one) hashclr(one->sha1); } +static int similarity_index(struct diff_filepair *p) +{ + int result = p->score * 100.0 / MAX_SCORE; + + /* Paranoia: guard against floating point rounding errors. */ + if (p->score == MAX_SCORE) + result = 100; + else if (result == 100) + result = 99; + + return result; +} + static void run_diff(struct diff_filepair *p, struct diff_options *o) { const char *pgm = external_diff(); @@ -1847,23 +1860,20 @@ static void run_diff(struct diff_filepair *p, struct diff_options *o) "similarity index %d%%\n" "copy from %s\n" "copy to %s\n", - (int)(0.5 + p->score * 100.0/MAX_SCORE), - name_munged, other_munged); + similarity_index(p), name_munged, other_munged); break; case DIFF_STATUS_RENAMED: len += snprintf(msg + len, sizeof(msg) - len, "similarity index %d%%\n" "rename from %s\n" "rename to %s\n", - (int)(0.5 + p->score * 100.0/MAX_SCORE), - name_munged, other_munged); + similarity_index(p), name_munged, other_munged); break; case DIFF_STATUS_MODIFIED: if (p->score) { len += snprintf(msg + len, sizeof(msg) - len, "dissimilarity index %d%%\n", - (int)(0.5 + p->score * - 100.0/MAX_SCORE)); + similarity_index(p)); complete_rewrite = 1; break; } @@ -2385,8 +2395,7 @@ static void diff_flush_raw(struct diff_filepair *p, } if (p->score) - sprintf(status, "%c%03d", p->status, - (int)(0.5 + p->score * 100.0/MAX_SCORE)); + sprintf(status, "%c%03d", p->status, similarity_index(p)); else { status[0] = p->status; status[1] = 0; @@ -2668,8 +2677,7 @@ static void show_rename_copy(const char *renamecopy, struct diff_filepair *p) { char *names = pprint_rename(p->one->path, p->two->path); - printf(" %s %s (%d%%)\n", renamecopy, names, - (int)(0.5 + p->score * 100.0/MAX_SCORE)); + printf(" %s %s (%d%%)\n", renamecopy, names, similarity_index(p)); free(names); show_mode_change(p, 0); } @@ -2693,7 +2701,7 @@ static void diff_summary(struct diff_filepair *p) if (p->score) { char *name = quote_one(p->two->path); printf(" rewrite %s (%d%%)\n", name, - (int)(0.5 + p->score * 100.0/MAX_SCORE)); + similarity_index(p)); free(name); show_mode_change(p, 0); } else show_mode_change(p, 1);
