From: Derrick Stolee Date: Thu, 12 Oct 2017 12:02:19 GMT Subject: [PATCH v5 3/4] sha1_name: parse less while finding common prefix Message-ID: <20171012120220.226427-4-dstolee@microsoft.com> In-Reply-To: <61168095-d392-39d2-ba65-823525239b5c@gmail.com> Create get_hex_char_from_oid() to parse oids one hex character at a time. This prevents unnecessary copying of hex characters in extend_abbrev_len() when finding the length of a common prefix. Signed-off-by: Derrick Stolee --- sha1_name.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff --git a/sha1_name.c b/sha1_name.c index 19603713f..fdd2711a6 100644 --- a/sha1_name.c +++ b/sha1_name.c @@ -480,13 +480,23 @@ struct min_abbrev_data { char *hex; }; +static inline char get_hex_char_from_oid(const struct object_id *oid, + unsigned int pos) +{ + static const char hex[] = "0123456789abcdef"; + + if ((pos & 1) == 0) + return hex[oid->hash[pos >> 1] >> 4]; + else + return hex[oid->hash[pos >> 1] & 0xf]; +} + static int extend_abbrev_len(const struct object_id *oid, void *cb_data) { struct min_abbrev_data *mad = cb_data; - char *hex = oid_to_hex(oid); unsigned int i = mad->init_len; - while (mad->hex[i] && mad->hex[i] == hex[i]) + while (mad->hex[i] && mad->hex[i] == get_hex_char_from_oid(oid, i)) i++; if (i < GIT_MAX_RAWSZ && i >= mad->cur_len) -- 2.14.1.538.g56ec8fc98.dirty