Speed up bitfields conversion

The old code took 3~5 times longer than the newer version.

src/base/CMakeLists.txt

@@ -17,6 +17,7 @@ add_library(qbt_base STATIC
     bittorrent/filterparserthread.h
     bittorrent/infohash.h
     bittorrent/loadtorrentparams.h
+    bittorrent/ltqbitarray.h
     bittorrent/ltqhash.h
     bittorrent/lttypecast.h
     bittorrent/magneturi.h
@@ -108,6 +109,7 @@ add_library(qbt_base STATIC
     bittorrent/filesearcher.cpp
     bittorrent/filterparserthread.cpp
     bittorrent/infohash.cpp
+    bittorrent/ltqbitarray.cpp
     bittorrent/magneturi.cpp
     bittorrent/nativesessionextension.cpp
     bittorrent/nativetorrentextension.cpp

src/base/base.pri

@@ -16,6 +16,7 @@ HEADERS += \
     $$PWD/bittorrent/filterparserthread.h \
     $$PWD/bittorrent/infohash.h \
     $$PWD/bittorrent/loadtorrentparams.h \
+    $$PWD/bittorrent/ltqbitarray.h \
     $$PWD/bittorrent/ltqhash.h \
     $$PWD/bittorrent/lttypecast.h \
     $$PWD/bittorrent/magneturi.h \
@@ -108,6 +109,7 @@ SOURCES += \
     $$PWD/bittorrent/filesearcher.cpp \
     $$PWD/bittorrent/filterparserthread.cpp \
     $$PWD/bittorrent/infohash.cpp \
+    $$PWD/bittorrent/ltqbitarray.cpp \
     $$PWD/bittorrent/magneturi.cpp \
     $$PWD/bittorrent/nativesessionextension.cpp \
     $$PWD/bittorrent/nativetorrentextension.cpp \

src/base/bittorrent/ltqbitarray.cpp

@@ -0,0 +1,59 @@
+/*
+ * Bittorrent Client using Qt and libtorrent.
+ * Copyright (C) 2022  Mike Tzou (Chocobo1)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ *
+ * In addition, as a special exception, the copyright holders give permission to
+ * link this program with the OpenSSL project's "OpenSSL" library (or with
+ * modified versions of it that use the same license as the "OpenSSL" library),
+ * and distribute the linked executables. You must obey the GNU General Public
+ * License in all respects for all of the code used other than "OpenSSL".  If you
+ * modify file(s), you may extend this exception to your version of the file(s),
+ * but you are not obligated to do so. If you do not wish to do so, delete this
+ * exception statement from your version.
+ */
+
+#include "ltqbitarray.h"
+
+#include <memory>
+
+#include <libtorrent/bitfield.hpp>
+
+#include <QBitArray>
+
+namespace
+{
+    unsigned char reverseByte(const unsigned char byte)
+    {
+        // https://graphics.stanford.edu/~seander/bithacks.html#ReverseByteWith64Bits
+        return (((byte * 0x80200802ULL) & 0x0884422110ULL) * 0x0101010101ULL) >> 32;
+    }
+}
+
+namespace BitTorrent::LT
+{
+    QBitArray toQBitArray(const lt::bitfield &bits)
+    {
+        const char *bitsData = bits.data();
+        const int dataLength = (bits.size() + 7) / 8;
+
+        auto tmp = std::make_unique<char []>(dataLength);
+        for (int i = 0; i < dataLength; ++i)
+            tmp[i] = reverseByte(bitsData[i]);
+
+        return QBitArray::fromBits(tmp.get(), bits.size());
+    }
+}

src/base/bittorrent/ltqbitarray.h

@@ -0,0 +1,38 @@
+/*
+ * Bittorrent Client using Qt and libtorrent.
+ * Copyright (C) 2022  Mike Tzou (Chocobo1)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ *
+ * In addition, as a special exception, the copyright holders give permission to
+ * link this program with the OpenSSL project's "OpenSSL" library (or with
+ * modified versions of it that use the same license as the "OpenSSL" library),
+ * and distribute the linked executables. You must obey the GNU General Public
+ * License in all respects for all of the code used other than "OpenSSL".  If you
+ * modify file(s), you may extend this exception to your version of the file(s),
+ * but you are not obligated to do so. If you do not wish to do so, delete this
+ * exception statement from your version.
+ */
+
+#pragma once
+
+#include <libtorrent/fwd.hpp>
+
+class QBitArray;
+
+namespace BitTorrent::LT
+{
+    QBitArray toQBitArray(const lt::bitfield &bits);
+}

src/base/bittorrent/peerinfo.cpp

@@ -30,6 +30,7 @@
 
 #include <QBitArray>
 
+#include "base/bittorrent/ltqbitarray.h"
 #include "base/bittorrent/torrent.h"
 #include "base/net/geoipmanager.h"
 #include "base/unicodestrings.h"
@@ -207,13 +208,7 @@ qlonglong PeerInfo::totalDownload() const
 
 QBitArray PeerInfo::pieces() const
 {
-    QBitArray result(m_nativeInfo.pieces.size());
-    for (int i = 0; i < result.size(); ++i)
-    {
-        if (m_nativeInfo.pieces[lt::piece_index_t {i}])
-            result.setBit(i, true);
-    }
-    return result;
+    return LT::toQBitArray(m_nativeInfo.pieces);
 }
 
 QString PeerInfo::connectionType() const

src/base/bittorrent/torrentimpl.cpp

@@ -58,6 +58,7 @@
 #include "common.h"
 #include "downloadpriority.h"
 #include "loadtorrentparams.h"
+#include "ltqbitarray.h"
 #include "ltqhash.h"
 #include "lttypecast.h"
 #include "peeraddress.h"
@@ -1250,15 +1251,7 @@ QVector<PeerInfo> TorrentImpl::peers() const
 QBitArray TorrentImpl::pieces() const
 {
     if (m_pieces.isEmpty())
-    {
-        m_pieces.resize(m_nativeStatus.pieces.size());
-        for (int i = 0; i < m_pieces.size(); ++i)
-        {
-            if (m_nativeStatus.pieces[lt::piece_index_t(i)])
-                m_pieces.setBit(i, true);
-        }
-    }
-
+        m_pieces = LT::toQBitArray(m_nativeStatus.pieces);
     return m_pieces;
 }