From aa22e8db2e4edee928ace2f016a170d52d14cb39 Mon Sep 17 00:00:00 2001
From: Michael Lotz <mmlr@mlotz.ch>
Date: Sat, 18 Oct 2008 20:12:09 +0000
Subject: [PATCH] Changed the score calculation for type ahead in the Tracker.
 Previously if there was at least one character matching at the start of any
 file it would have gotten a score >= 1. This rendered the substring matching
 completely useless as soon as this happened, because it would always get a
 score < 1 depending on the position of the occurance. Now substring matching
 is the first (and without word mode, the only) score to get. Since the score
 depends on the position of the match, this doesn't change anything for exact
 matches at the beginning, but it does allow for substring matches even if
 there is a file starting with the same letter as the search string. Also use
 strcasestr() instead of strstr() to make the search case insensitive.

git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@28233 a95241bf-73f2-0310-859d-f6bbb57e9c96
---
 src/kits/tracker/Utilities.cpp | 39 ++++++++--------------------------
 1 file changed, 9 insertions(+), 30 deletions(-)

diff --git a/src/kits/tracker/Utilities.cpp b/src/kits/tracker/Utilities.cpp
index 1bba96aa8f..a8e0bca1c2 100644
--- a/src/kits/tracker/Utilities.cpp
+++ b/src/kits/tracker/Utilities.cpp
@@ -1589,35 +1589,20 @@ float
 ComputeTypeAheadScore(const char *text, const char *match, size_t matchLength,
 	bool wordMode)
 {
-	float first = -1;
-	float second = -1;
-	float third = -1;
-
 	// highest score: exact match
-	float score = 0;
-	size_t pos = 0;
-	for (; pos < matchLength; pos++) {
-		if (text[pos] == '\0') {
-			score = 0;
-			break;
-		}
-		if (tolower(text[pos]) != tolower(match[pos]))
-			break;
+	const char* found = strcasestr(text, match);
+	if (found != NULL) {
+		if (found == text)
+			return kExactMatchScore;
 
-		score++;
+		return 1.f / (found - text);
 	}
-	if (pos == matchLength) {
-		// we don't need to look any further
-		return kExactMatchScore;
-	}
-
-	first = score;
 
 	// there was no exact match
 
 	// second best: all characters at word beginnings
 	if (wordMode) {
-		score = 0;
+		float score = 0;
 		for (int32 j = 0, k = 0; match[j]; j++) {
 			while (text[k]
 				&& tolower(text[k]) != tolower(match[j])) {
@@ -1642,17 +1627,11 @@ ComputeTypeAheadScore(const char *text, const char *match, size_t matchLength,
 			score += 1.f / (k + 1);
 			k++;
 		}
-		second = score;
+
+		return score;
 	}
 
-	// acceptable last: exact match inside the string
-	score = 0;
-	const char* found = strstr(text + 1, match);
-	if (found != NULL)
-		score = 1.f / (found - text);
-	third = score;
-
-	return max_c(first, max_c(second, third));
+	return -1;
 }