From 590577f88042fd5bb281d9576324b6f709a07dc4 Mon Sep 17 00:00:00 2001
From: Daniel Schadt <kingdread@gmx.de>
Date: Wed, 9 Apr 2025 12:43:09 +0200
Subject: speed up multiplication

---
 src/block.rs | 27 ++++++++++++++++-----------
 1 file changed, 16 insertions(+), 11 deletions(-)

(limited to 'src/block.rs')

diff --git a/src/block.rs b/src/block.rs
index abd7ff7..e9ba527 100644
--- a/src/block.rs
+++ b/src/block.rs
@@ -134,19 +134,24 @@ impl IndexMut<usize> for Block {
 
 impl Mul<u32> for Block {
     type Output = Block;
-    fn mul(self, rhs: u32) -> Block {
-        match rhs {
-            0 => Block::NULL,
-            1 => self,
-            2 => {
-                let mut result = self << 1;
-                if self[0] & 0x80 != 0 {
-                    result[15] ^= 135;
+    fn mul(mut self, mut rhs: u32) -> Block {
+        loop {
+            match rhs {
+                0 => break Block::NULL,
+                1 => break self,
+                2 => {
+                    let mut result = self << 1;
+                    if self[0] & 0x80 != 0 {
+                        result[15] ^= 135;
+                    }
+                    break result;
                 }
-                result
+                _ if rhs % 2 == 0 => {
+                    self = self * 2;
+                    rhs = rhs / 2;
+                }
+                _ => break self * (rhs - 1) ^ self,
             }
-            _ if rhs % 2 == 0 => self * 2 * (rhs / 2),
-            _ => self * (rhs - 1) ^ self,
         }
     }
 }
-- 
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