From e4c889ae1648a711b6763eda672601d0885fe145 Mon Sep 17 00:00:00 2001
From: "Dylan K. Taylor" <odigiman@gmail.com>
Date: Wed, 18 Jan 2017 20:04:19 +0000
Subject: [PATCH] Check if the array contents are already the same, massive
 performance improvement for Anvil in a lot of cases

---
 src/pocketmine/level/format/io/ChunkUtils.php | 59 +++++++++++--------
 1 file changed, 33 insertions(+), 26 deletions(-)

diff --git a/src/pocketmine/level/format/io/ChunkUtils.php b/src/pocketmine/level/format/io/ChunkUtils.php
index c44130f29..6fbc56934 100644
--- a/src/pocketmine/level/format/io/ChunkUtils.php
+++ b/src/pocketmine/level/format/io/ChunkUtils.php
@@ -34,19 +34,22 @@ class ChunkUtils{
 	 */
 	public static final function reorderByteArray(string $array) : string{
 		$result = str_repeat("\x00", 4096);
-		$i = 0;
-		$zM = 0;
-		$yM = 0;
-		for($x = 0; $x < 16; ++$x){
-			$zM = $x + 256;
-			for($z = $x; $z < $zM; $z += 16){
-				$yM = $z + 4096;
-				for($y = $z; $y < $yM; $y += 256){
-					$result{$i} = $array{$y};
-					++$i;
+		if($array !== $result){
+			$i = 0;
+			$zM = 0;
+			$yM = 0;
+			for($x = 0; $x < 16; ++$x){
+				$zM = $x + 256;
+				for($z = $x; $z < $zM; $z += 16){
+					$yM = $z + 4096;
+					for($y = $z; $y < $yM; $y += 256){
+						$result{$i} = $array{$y};
+						++$i;
+					}
 				}
 			}
 		}
+
 		return $result;
 	}
 
@@ -60,26 +63,30 @@ class ChunkUtils{
 	 */
 	public static final function reorderNibbleArray(string $array, string $commonValue = "\x00") : string{
 		$result = str_repeat($commonValue, 2048);
-		$i = 0;
-		for($x = 0; $x < 8; ++$x){
-			for($z = 0; $z < 16; ++$z){
-				$zx = (($z << 3) | $x);
-				for($y = 0; $y < 8; ++$y){
-					$j = (($y << 8) | $zx);
-					$j80 = ($j | 0x80);
-					if($array{$j} === $commonValue and $array{$j80} === $commonValue){
-						//values are already filled
-					}else{
-						$i1 = ord($array{$j});
-						$i2 = ord($array{$j80});
-						$result{$i}        = chr(($i2 << 4) | ($i1 & 0x0f));
-						$result{$i | 0x80} = chr(($i1 >> 4) | ($i2 & 0xf0));
+
+		if($array !== $result){
+			$i = 0;
+			for($x = 0; $x < 8; ++$x){
+				for($z = 0; $z < 16; ++$z){
+					$zx = (($z << 3) | $x);
+					for($y = 0; $y < 8; ++$y){
+						$j = (($y << 8) | $zx);
+						$j80 = ($j | 0x80);
+						if($array{$j} === $commonValue and $array{$j80} === $commonValue){
+							//values are already filled
+						}else{
+							$i1 = ord($array{$j});
+							$i2 = ord($array{$j80});
+							$result{$i}        = chr(($i2 << 4) | ($i1 & 0x0f));
+							$result{$i | 0x80} = chr(($i1 >> 4) | ($i2 & 0xf0));
+						}
+						$i++;
 					}
-					$i++;
 				}
+				$i += 128;
 			}
-			$i += 128;
 		}
+
 		return $result;
 	}