From 923fa978088f4c044eec528d9472962d9c9d13c3 Mon Sep 17 00:00:00 2001 From: Andrew Tridgell Date: Tue, 5 Jan 1999 01:15:32 +0000 Subject: [PATCH] an optimization that tries to make rsync choose adjacent matches if multiple matching blocks are available. This make the run-length coding of the output more efficient. --- match.c | 22 +++++++++++++++++++++- 1 file changed, 21 insertions(+), 1 deletion(-) diff --git a/match.c b/match.c index 29b52516..38e8aa01 100644 --- a/match.c +++ b/match.c @@ -130,12 +130,16 @@ static void hash_search(int f,struct sum_struct *s, struct map_struct *buf,OFF_T len) { OFF_T offset; - int j,k; + int j,k, last_i; int end; char sum2[SUM_LENGTH]; uint32 s1, s2, sum; schar *map; + /* last_i is used to encourage adjacent matches, allowing the RLL coding of the + output to work more efficiently */ + last_i = -1; + if (verbose > 2) rprintf(FINFO,"hash search b=%d len=%d\n",s->n,(int)len); @@ -191,6 +195,22 @@ static void hash_search(int f,struct sum_struct *s, false_alarms++; continue; } + + /* we've found a match, but now check to see + if last_i can hint at a better match */ + for (j++; jcount && targets[j].t == t; j++) { + int i2 = targets[j].t; + if (i2 == last_i + 1) { + if (sum != s->sums[i2].sum1) break; + if (memcmp(sum2,s->sums[i2].sum2,csum_length) != 0) break; + /* we've found an adjacent match - the RLL coder + will be happy */ + i = i2; + break; + } + } + + last_i = i; matched(f,s,buf,offset,i); offset += s->sums[i].len - 1; -- 2.34.1