From 0dd7e398c7c390fc46ed9d53e7de5ff101a6f6b1 Mon Sep 17 00:00:00 2001
From: Ilya Gorbunov <ilya.gorbunov@jetbrains.com>
Date: Wed, 28 Oct 2015 21:55:51 +0300
Subject: [PATCH] Use reverse indexed iteration in last and lastOrNull with
 predicate for CharSequences and Strings.

---
 libraries/stdlib/src/generated/_Strings.kt    | 46 +++++++------------
 .../src/templates/Elements.kt                 |  4 +-
 2 files changed, 18 insertions(+), 32 deletions(-)

diff --git a/libraries/stdlib/src/generated/_Strings.kt b/libraries/stdlib/src/generated/_Strings.kt
index 336ed95325f..211517c455e 100644
--- a/libraries/stdlib/src/generated/_Strings.kt
+++ b/libraries/stdlib/src/generated/_Strings.kt
@@ -265,16 +265,11 @@ public fun String.last(): Char {
  * @throws [NoSuchElementException] if no such character is found.
  */
 public inline fun CharSequence.last(predicate: (Char) -> Boolean): Char {
-    var last: Char? = null
-    var found = false
-    for (element in this) {
-        if (predicate(element)) {
-            last = element
-            found = true
-        }
+    for (index in this.indices.reversed()) {
+        val element = this[index]
+        if (predicate(element)) return element
     }
-    if (!found) throw NoSuchElementException("Collection doesn't contain any element matching the predicate.")
-    return last as Char
+    throw NoSuchElementException("Collection doesn't contain any element matching the predicate.")
 }
 
 /**
@@ -283,16 +278,11 @@ public inline fun CharSequence.last(predicate: (Char) -> Boolean): Char {
  */
 @Deprecated("Provided for binary compatibility", level = DeprecationLevel.HIDDEN)
 public inline fun String.last(predicate: (Char) -> Boolean): Char {
-    var last: Char? = null
-    var found = false
-    for (element in this) {
-        if (predicate(element)) {
-            last = element
-            found = true
-        }
+    for (index in this.indices.reversed()) {
+        val element = this[index]
+        if (predicate(element)) return element
     }
-    if (!found) throw NoSuchElementException("Collection doesn't contain any element matching the predicate.")
-    return last as Char
+    throw NoSuchElementException("Collection doesn't contain any element matching the predicate.")
 }
 
 /**
@@ -314,13 +304,11 @@ public fun String.lastOrNull(): Char? {
  * Returns the last character matching the given [predicate], or `null` if no such character was found.
  */
 public inline fun CharSequence.lastOrNull(predicate: (Char) -> Boolean): Char? {
-    var last: Char? = null
-    for (element in this) {
-        if (predicate(element)) {
-            last = element
-        }
+    for (index in this.indices.reversed()) {
+        val element = this[index]
+        if (predicate(element)) return element
     }
-    return last
+    return null
 }
 
 /**
@@ -328,13 +316,11 @@ public inline fun CharSequence.lastOrNull(predicate: (Char) -> Boolean): Char? {
  */
 @Deprecated("Provided for binary compatibility", level = DeprecationLevel.HIDDEN)
 public inline fun String.lastOrNull(predicate: (Char) -> Boolean): Char? {
-    var last: Char? = null
-    for (element in this) {
-        if (predicate(element)) {
-            last = element
-        }
+    for (index in this.indices.reversed()) {
+        val element = this[index]
+        if (predicate(element)) return element
     }
-    return last
+    return null
 }
 
 /**
diff --git a/libraries/tools/kotlin-stdlib-gen/src/templates/Elements.kt b/libraries/tools/kotlin-stdlib-gen/src/templates/Elements.kt
index f05f5f1f8e0..2851e9bc68f 100644
--- a/libraries/tools/kotlin-stdlib-gen/src/templates/Elements.kt
+++ b/libraries/tools/kotlin-stdlib-gen/src/templates/Elements.kt
@@ -643,7 +643,7 @@ fun elements(): List<GenericFunction> {
             """
         }
 
-        body(ArraysOfPrimitives, ArraysOfObjects, Lists) {
+        body(CharSequences, Strings, ArraysOfPrimitives, ArraysOfObjects, Lists) {
             """
             for (index in this.indices.reversed()) {
                 val element = this[index]
@@ -678,7 +678,7 @@ fun elements(): List<GenericFunction> {
             """
         }
 
-        body(ArraysOfPrimitives, ArraysOfObjects, Lists) {
+        body(CharSequences, Strings, ArraysOfPrimitives, ArraysOfObjects, Lists) {
             """
             for (index in this.indices.reversed()) {
                 val element = this[index]