diff options
Diffstat (limited to 'bisect.c')
| -rw-r--r-- | bisect.c | 50 |
1 files changed, 39 insertions, 11 deletions
@@ -585,16 +585,49 @@ struct commit_list *filter_skipped(struct commit_list *list, return filtered; } -static struct commit_list *apply_skip_ratio(struct commit_list *list, - int count, - int skip_num, int skip_denom) +#define PRN_MODULO 32768 + +/* + * This is a pseudo random number generator based on "man 3 rand". + * It is not used properly because the seed is the argument and it + * is increased by one between each call, but that should not matter + * for this application. + */ +int get_prn(int count) { + count = count * 1103515245 + 12345; + return ((unsigned)(count/65536) % PRN_MODULO); +} + +/* + * Custom integer square root from + * http://en.wikipedia.org/wiki/Integer_square_root + */ +static int sqrti(int val) +{ + float d, x = val; + + if (val == 0) + return 0; + + do { + float y = (x + (float)val / x) / 2; + d = (y > x) ? y - x : x - y; + x = y; + } while (d >= 0.5); + + return (int)x; +} + +static struct commit_list *skip_away(struct commit_list *list, int count) { - int index, i; struct commit_list *cur, *previous; + int prn, index, i; + + prn = get_prn(count); + index = (count * prn / PRN_MODULO) * sqrti(prn) / sqrti(PRN_MODULO); cur = list; previous = NULL; - index = count * skip_num / skip_denom; for (i = 0; cur; cur = cur->next, i++) { if (i == index) { @@ -614,7 +647,6 @@ static struct commit_list *managed_skipped(struct commit_list *list, struct commit_list **tried) { int count, skipped_first; - int skip_num, skip_denom; *tried = NULL; @@ -626,11 +658,7 @@ static struct commit_list *managed_skipped(struct commit_list *list, if (!skipped_first) return list; - /* Use alternatively 1/5, 2/5 and 3/5 as skip ratio. */ - skip_num = count % 3 + 1; - skip_denom = 5; - - return apply_skip_ratio(list, count, skip_num, skip_denom); + return skip_away(list, count); } static void bisect_rev_setup(struct rev_info *revs, const char *prefix, |