From: Lucas Bajolet <r4pass@hotmail.com>
Date: Fri, 25 Sep 2015 15:00:48 +0000 (-0400)
Subject: lib/core: Improve performances of last_index_of_from
X-Git-Tag: v0.7.8~1^2~3
X-Git-Url: http://nitlanguage.org

lib/core: Improve performances of last_index_of_from

Signed-off-by: Lucas Bajolet <r4pass@hotmail.com>
---

diff --git a/lib/core/collection/abstract_collection.nit b/lib/core/collection/abstract_collection.nit
index 5192797..b65db67 100644
--- a/lib/core/collection/abstract_collection.nit
+++ b/lib/core/collection/abstract_collection.nit
@@ -833,18 +833,13 @@ interface SequenceRead[E]
 	#     assert a.last_index_of_from(20, 2)   == 1
 	#     assert a.last_index_of_from(20, 1)   == 1
 	#     assert a.last_index_of_from(20, 0)   == -1
-	fun last_index_of_from(item: nullable Object, pos: Int): Int
-	do
-		var res = -1
-		var p = 0
-		var i = iterator
-		while i.is_ok do
-			if p>pos then break
-			if i.item == item then res = p
-			i.next
-			p += 1
+	fun last_index_of_from(item: nullable Object, pos: Int): Int do
+		var i = pos
+		while i >= 0 do
+			if self[i] == item then return i
+			i -= 1
 		end
-		return res
+		return -1
 	end
 
 	# Two sequences are equals if they have the same items in the same order.
diff --git a/lib/core/text/abstract_text.nit b/lib/core/text/abstract_text.nit
index 63fb920..1fcb0d9 100644
--- a/lib/core/text/abstract_text.nit
+++ b/lib/core/text/abstract_text.nit
@@ -146,15 +146,7 @@ abstract class Text
 	# Returns -1 if not found
 	#
 	# DEPRECATED : Use self.chars.last_index_of_from instead
-	fun last_index_of_from(item: Char, pos: Int): Int
-	do
-		var iter = self.chars.reverse_iterator_from(pos)
-		while iter.is_ok do
-			if iter.item == item then return iter.index
-			iter.next
-		end
-		return -1
-	end
+	fun last_index_of_from(item: Char, pos: Int): Int do return chars.last_index_of_from(item, pos)
 
 	# Gets an iterator on the chars of self
 	#