The implementations in diff.c to detect moved lines needs to compare strings and hash strings, which is implemented in that file, as well as in the xdiff library.
Remove the rather recent implementation in diff.c and rely on the well exercised code in the xdiff lib. With this change the hash used for bucketing the strings for the moved line detection changes from FNV32 (that is provided via the hashmaps memhash) to DJB2 (which is used internally in xdiff). Benchmarks found on the web[1] do not indicate that these hashes are different in performance for readable strings. [1] https://softwareengineering.stackexchange.com/questions/49550/which-hashing-algorithm-is-best-for-uniqueness-and-speed Signed-off-by: Stefan Beller <sbel...@google.com> --- diff.c | 82 ++++-------------------------------------------------------------- 1 file changed, 4 insertions(+), 78 deletions(-) diff --git a/diff.c b/diff.c index c4a669ffa8..e6814b9e9c 100644 --- a/diff.c +++ b/diff.c @@ -707,88 +707,14 @@ struct moved_entry { struct moved_entry *next_line; }; -static int next_byte(const char **cp, const char **endp, - const struct diff_options *diffopt) -{ - int retval; - - if (*cp >= *endp) - return -1; - - if (isspace(**cp)) { - if (DIFF_XDL_TST(diffopt, IGNORE_WHITESPACE_CHANGE)) { - while (*cp < *endp && isspace(**cp)) - (*cp)++; - /* - * After skipping a couple of whitespaces, - * we still have to account for one space. - */ - return (int)' '; - } - - if (DIFF_XDL_TST(diffopt, IGNORE_WHITESPACE)) { - while (*cp < *endp && isspace(**cp)) - (*cp)++; - /* - * return the first non-ws character via the usual - * below, unless we ate all of the bytes - */ - if (*cp >= *endp) - return -1; - } - } - - retval = (unsigned char)(**cp); - (*cp)++; - return retval; -} - static int moved_entry_cmp(const struct diff_options *diffopt, const struct moved_entry *a, const struct moved_entry *b, const void *keydata) { - const char *ap = a->es->line, *ae = a->es->line + a->es->len; - const char *bp = b->es->line, *be = b->es->line + b->es->len; - - if (!(diffopt->xdl_opts & XDF_WHITESPACE_FLAGS)) - return a->es->len != b->es->len || memcmp(ap, bp, a->es->len); - - if (DIFF_XDL_TST(diffopt, IGNORE_WHITESPACE_AT_EOL)) { - while (ae > ap && isspace(ae[-1])) - ae--; - while (be > bp && isspace(be[-1])) - be--; - } - - while (1) { - int ca, cb; - ca = next_byte(&ap, &ae, diffopt); - cb = next_byte(&bp, &be, diffopt); - if (ca != cb) - return 1; - if (ca < 0) - return 0; - } -} - -static unsigned get_string_hash(struct emitted_diff_symbol *es, struct diff_options *o) -{ - if (o->xdl_opts & XDF_WHITESPACE_FLAGS) { - static struct strbuf sb = STRBUF_INIT; - const char *ap = es->line, *ae = es->line + es->len; - int c; - - strbuf_reset(&sb); - while (ae > ap && isspace(ae[-1])) - ae--; - while ((c = next_byte(&ap, &ae, o)) >= 0) - strbuf_addch(&sb, c); - - return memhash(sb.buf, sb.len); - } else { - return memhash(es->line, es->len); - } + return !xdiff_compare_lines(a->es->line, a->es->len, + b->es->line, b->es->len, + diffopt->xdl_opts); } static struct moved_entry *prepare_entry(struct diff_options *o, @@ -797,7 +723,7 @@ static struct moved_entry *prepare_entry(struct diff_options *o, struct moved_entry *ret = xmalloc(sizeof(*ret)); struct emitted_diff_symbol *l = &o->emitted_symbols->buf[line_no]; - ret->ent.hash = get_string_hash(l, o); + ret->ent.hash = xdiff_hash_string(l->line, l->len, o->xdl_opts); ret->es = l; ret->next_line = NULL; -- 2.15.0.rc2.6.g953226eb5f
