fzy

commit 48d4a8883e90809b05d3401ca8e3cdb1b83fbade
parent bccdb957aab8e2be522f2f6eaa696d0c838aed49
Author: John Hawthorn <john@hawthorn.email>
Date:   Sat, 13 Oct 2018 14:05:10 -0700

Precompute tolower in match_positions

This makes match_positions significantly faster on MacOS by calling
tolower() O(N) times instead of O(N*N)

Before:

    $ time ./fzy -e linux --benchmark < linux_files.txt
    ./fzy -e linux --benchmark < linux_files.txt  13.24s user 0.03s system 381% cpu 3.483 total

After:

    $ time ./fzy -e linux --benchmark < linux_files.txt
    ./fzy -e linux --benchmark < linux_files.txt  4.57s user 0.02s system 381% cpu 1.204 total

Diffstat:
M
src/match.c
 | 
11
++++++++++-

1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/src/match.c b/src/match.c
@@ -94,6 +94,15 @@ score_t match_positions(const char *needle, const char *haystack, size_t *positi
 		return SCORE_MIN;
 	}
 
+	char lower_needle[n];
+	char lower_haystack[m];
+
+	for (int i = 0; i < n; i++)
+		lower_needle[i] = tolower(needle[i]);
+
+	for (int i = 0; i < m; i++)
+		lower_haystack[i] = tolower(haystack[i]);
+
 	score_t match_bonus[m];
 	score_t D[n][m], M[n][m];
 
@@ -108,7 +117,7 @@ score_t match_positions(const char *needle, const char *haystack, size_t *positi
 		score_t gap_score = i == n - 1 ? SCORE_GAP_TRAILING : SCORE_GAP_INNER;
 
 		for (int j = 0; j < m; j++) {
-			if (tolower(needle[i]) == tolower(haystack[j])) {
+			if (lower_needle[i] == lower_haystack[j]) {
 				score_t score = SCORE_MIN;
 				if (!i) {
 					score = (j * SCORE_GAP_LEADING) + match_bonus[j];