From f485719012287cee0c9e5c6eb936d39092bba9b3 Mon Sep 17 00:00:00 2001
From: David Faure <faure@kde.org>
Date: Mon, 1 Oct 2018 19:48:28 +0200
Subject: [PATCH] kimg_rgb: optimize away QRegExp and QString::fromLocal8Bit.

Summary:
The code is even simpler this way.

Found by using heaptrack.

Test Plan: the unittest for rgb still passes.

Reviewers: cfeck

Reviewed By: cfeck

Subscribers: jtamate, kde-frameworks-devel

Tags: #frameworks

Differential Revision: https://phabricator.kde.org/D15890
---
 src/imageformats/rgb.cpp | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/src/imageformats/rgb.cpp b/src/imageformats/rgb.cpp
index 19e432d..a8a6eba 100644
--- a/src/imageformats/rgb.cpp
+++ b/src/imageformats/rgb.cpp
@@ -686,8 +686,8 @@ bool RGBHandler::canRead(QIODevice *device)
         return false;
     }
 
-    qint64 oldPos = device->pos();
-    QByteArray head = device->readLine(64);
+    const qint64 oldPos = device->pos();
+    const QByteArray head = device->readLine(64);
     int readBytes = head.size();
 
     if (device->isSequential()) {
@@ -699,10 +699,7 @@ bool RGBHandler::canRead(QIODevice *device)
         device->seek(oldPos);
     }
 
-    const QRegExp regexp(QLatin1String("^\x01\xda\x01[\x01\x02]"));
-    QString data(QString::fromLocal8Bit(head));
-
-    return data.contains(regexp);
+    return head.size() >= 4 && head.startsWith("\x01\xda\x01") && (head[3] == 1 || head[3] == 2);
 }
 
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