From 6df8efd433b22c4bcb1ae1e7afc24fad389538c1 Mon Sep 17 00:00:00 2001
From: Michael Mikonos <127171689+mknos@users.noreply.github.com>
Date: Wed, 24 Jan 2024 19:25:46 +0800
Subject: [PATCH 1/2] ed: simplify backwards search

* In edSearchBackwards(), init $line index directly instead of copying value from $start
* I found this by accident when reading the code
* Test jumps to line 60, finds "perl" patten backwards on line 9 then again on 7

%perl ed -p '>>> ' awk
4595
>>> 60
open(TMPOUT, '+>', ($tmpout = "/tmp/a2pout.$$"))    ||
>>> ?perl
License: perl
>>> n
9	License: perl
>>> ?perl
Author: Tom Christiansen, tchrist@perl.com
>>> n
7	Author: Tom Christiansen, tchrist@perl.com
>>> q
---
 bin/ed | 7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

diff --git a/bin/ed b/bin/ed
index 91c7a01c..482e129b 100755
--- a/bin/ed
+++ b/bin/ed
@@ -1111,13 +1111,8 @@ sub edSearchForward {
 
 sub edSearchBackward {
     my($pattern) = @_;
-    my($line,$start);
 
-    # brute force search...
-
-    $start = $CurrentLineNum > 1 ? $CurrentLineNum - 1 : maxline();
-
-    $line = $start;
+    my $line = $CurrentLineNum > 1 ? $CurrentLineNum - 1 : maxline();
 
     while ($line > 0) {
         if ($lines[$line] =~ /$pattern/) {

From 56cd01904d0a0cf4e19f36603029db9178e56524 Mon Sep 17 00:00:00 2001
From: Michael Mikonos <127171689+mknos@users.noreply.github.com>
Date: Wed, 24 Jan 2024 21:46:37 +0800
Subject: [PATCH 2/2] merge loops

---
 bin/ed | 15 ++-------------
 1 file changed, 2 insertions(+), 13 deletions(-)

diff --git a/bin/ed b/bin/ed
index 482e129b..392b852b 100755
--- a/bin/ed
+++ b/bin/ed
@@ -1112,23 +1112,12 @@ sub edSearchForward {
 sub edSearchBackward {
     my($pattern) = @_;
 
-    my $line = $CurrentLineNum > 1 ? $CurrentLineNum - 1 : maxline();
-
-    while ($line > 0) {
+    my @idx = ($CurrentLineNum .. maxline(), 1 .. ($CurrentLineNum - 1));
+    foreach my $line (reverse @idx) {
         if ($lines[$line] =~ /$pattern/) {
             return $line;
         }
-        $line--;
     }
-
-    $line = maxline();
-    while ($line >= $CurrentLineNum) {
-        if ($lines[$line] =~ /$pattern/) {
-            return $line;
-        }
-        $line--;
-    }
-
     return 0;
 }