From: Eric Wong <e@80x24.org>
Date: Sun, 23 Aug 2015 02:40:19 +0000 (+0000)
Subject: GitCatFile: use offset for read instead of appending
X-Git-Tag: v1.0.0~996
X-Git-Url: http://www.git.stargrave.org/?a=commitdiff_plain;h=8fef5b14a9c397eeece31c54c8f0d0c90a3ad2a6;p=public-inbox.git

GitCatFile: use offset for read instead of appending

There is no need to perform string appends when the
"read" and "sysread" functions take an offset argument
to append to the given buffer.

This avoid needless string creation.
---

diff --git a/lib/PublicInbox/GitCatFile.pm b/lib/PublicInbox/GitCatFile.pm
index 8bc6a238..9bffce2a 100644
--- a/lib/PublicInbox/GitCatFile.pm
+++ b/lib/PublicInbox/GitCatFile.pm
@@ -68,17 +68,17 @@ sub cat_file {
 
 	my $size = $1;
 	my $bytes_left = $size;
-	my $buf;
+	my $offset = 0;
 	my $rv = '';
 
 	while ($bytes_left) {
-		my $read = read($in, $buf, $bytes_left);
-		defined($read) or die "read pipe failed: $!\n";
-		$rv .= $buf;
+		my $read = read($in, $rv, $bytes_left, $offset);
+		defined($read) or die "sysread pipe failed: $!\n";
 		$bytes_left -= $read;
+		$offset += $read;
 	}
 
-	my $read = read($in, $buf, 1);
+	my $read = read($in, my $buf, 1);
 	defined($read) or die "read pipe failed: $!\n";
 	if ($read != 1 || $buf ne "\n") {
 		die "newline missing after blob\n";