1. rcrnstn/fzy
  2. Commit 20d2274a9383c5e585b87b1225a7da3cf1dcb194
Browse code

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

John Hawthorn authored on 13/10/2018 21:05:10
Showing 1 changed files
src/match.c
History View file @ 20d2274
... ... 
@@ -94,6 +94,15 @@ score_t match_positions(const char *needle, const char *haystack, size_t *positi
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 		return SCORE_MIN;
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 	}
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+	char lower_needle[n];
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+	char lower_haystack[m];
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+
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+	for (int i = 0; i < n; i++)
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+		lower_needle[i] = tolower(needle[i]);
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+
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+	for (int i = 0; i < m; i++)
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+		lower_haystack[i] = tolower(haystack[i]);
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+
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 	score_t match_bonus[m];
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 	score_t D[n][m], M[n][m];
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... ... 
@@ -108,7 +117,7 @@ score_t match_positions(const char *needle, const char *haystack, size_t *positi
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 		score_t gap_score = i == n - 1 ? SCORE_GAP_TRAILING : SCORE_GAP_INNER;
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 		for (int j = 0; j < m; j++) {
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-			if (tolower(needle[i]) == tolower(haystack[j])) {
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+			if (lower_needle[i] == lower_haystack[j]) {
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 				score_t score = SCORE_MIN;
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 				if (!i) {
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 					score = (j * SCORE_GAP_LEADING) + match_bonus[j];