Database read optimizations

Hard to believe there was still more room to improve on this, but I
found an easily correctable oversight tonight. Our databases (both sync
and local) contain many blank lines, and we were not moving onto the
next line right away in these cases; instead we would proceed through
our strcmp() conditional checks as normal.

Some local numbers follow to show the effects of this patch:

Sync `-Ss foobarbaz`:
71,709 blank lines skipped early
~1,505,889 strcmp() calls avoided (21 per line)
~15% speed improvement (.210 --> .179 sec)

Local `-Qs foobarbaz`:
6,823 blank lines skipped early
115,991 strcmp() calls avoided (17 per line)
~6% speed improvement (.080 -> .071 sec)

Signed-off-by: Dan McGee <dan@archlinux.org>

1 files changed, 4 insertions, 1 deletions

diff --git a/lib/libalpm/be_sync.c b/lib/libalpm/be_sync.c
index ac99e05e..12d5b7fe 100644
--- a/lib/libalpm/be_sync.c
+++ b/lib/libalpm/be_sync.c
@@ -526,7 +526,10 @@ static int sync_db_read(alpm_db_t *db, struct archive *archive,
 		int ret;
 		while((ret = _alpm_archive_fgets(archive, &buf)) == ARCHIVE_OK) {
 			char *line = buf.line;
-			_alpm_strip_newline(line);
+			if(_alpm_strip_newline(line) == 0) {
+				/* length of stripped line was zero */
+				continue;
+			}
 
 			if(strcmp(line, "%NAME%") == 0) {
 				READ_NEXT();