From 731f2d7e6db109bc0d853f2d16fd7185d4a90d06 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20T=C5=AFma?= <tumic@cbox.cz>
Date: Wed, 3 Feb 2021 22:16:00 +0100
Subject: [PATCH] Added an optimized subfile block read

---
 src/map/IMG/huffmanbuffer.cpp |  6 +-----
 src/map/IMG/lblfile.cpp       |  5 ++---
 src/map/IMG/subfile.cpp       | 26 +++++++++++++++++++++++++-
 src/map/IMG/subfile.h         |  2 ++
 4 files changed, 30 insertions(+), 9 deletions(-)

diff --git a/src/map/IMG/huffmanbuffer.cpp b/src/map/IMG/huffmanbuffer.cpp
index e00b51c3..a53c687b 100644
--- a/src/map/IMG/huffmanbuffer.cpp
+++ b/src/map/IMG/huffmanbuffer.cpp
@@ -16,9 +16,5 @@ bool HuffmanBuffer::load(const RGNFile *rgn, SubFile::Handle &rgnHdl)
 	};
 
 	resize(recordSize);
-	for (int i = 0; i < QByteArray::size(); i++)
-		if (!rgn->readByte(rgnHdl, (quint8*)(data() + i)))
-			return false;
-
-	return true;
+	return rgn->read(rgnHdl, (quint8*)data(), recordSize);
 }
diff --git a/src/map/IMG/lblfile.cpp b/src/map/IMG/lblfile.cpp
index 10d748d7..0555aa3d 100644
--- a/src/map/IMG/lblfile.cpp
+++ b/src/map/IMG/lblfile.cpp
@@ -338,9 +338,8 @@ QImage LBLFile::readImage(Handle &hdl, quint32 id) const
 		return QImage();
 	QByteArray ba;
 	ba.resize(_rasters.at(id).size);
-	for (int i = 0; i < ba.size(); i++)
-		if (!readByte(hdl, (quint8*)(ba.data() + i)))
-			return QImage();
+	if (!read(hdl, (quint8*)ba.data(), _rasters.at(id).size))
+		return QImage();
 
 	return QImage::fromData(ba);
 }
diff --git a/src/map/IMG/subfile.cpp b/src/map/IMG/subfile.cpp
index 865c190d..ce1d1373 100644
--- a/src/map/IMG/subfile.cpp
+++ b/src/map/IMG/subfile.cpp
@@ -1,4 +1,4 @@
-#include <QFile>
+#include <cstring>
 #include "img.h"
 #include "subfile.h"
 
@@ -115,3 +115,27 @@ bool SubFile::readVBitfield32(Handle &hdl, quint32 &bitfield) const
 
 	return true;
 }
+
+bool SubFile::read(Handle &handle, quint8 *buff, quint32 size) const
+{
+	while (size) {
+		quint32 remaining = handle._data.size() - handle._blockPos;
+		if (size < remaining) {
+			memcpy(buff, handle._data.constData() + handle._blockPos, size);
+			handle._blockPos += size;
+			handle._pos++;
+			return true;
+		} else {
+			memcpy(buff, handle._data.constData() + handle._blockPos,
+			  remaining);
+			buff += remaining;
+			size -= remaining;
+			handle._blockPos = 0;
+			handle._pos += remaining;
+			if (!seek(handle, handle._pos))
+				return false;
+		}
+	}
+
+	return true;
+}
diff --git a/src/map/IMG/subfile.h b/src/map/IMG/subfile.h
index 748fba82..cc86ba63 100644
--- a/src/map/IMG/subfile.h
+++ b/src/map/IMG/subfile.h
@@ -60,6 +60,8 @@ public:
 	bool seek(Handle &handle, quint32 pos) const;
 	quint32 pos(Handle &handle) const {return handle._pos;}
 
+	bool read(Handle &handle, quint8 *buff, quint32 size) const;
+
 	bool readByte(Handle &handle, quint8 *val) const
 	{
 		*val = handle._data.at(handle._blockPos++);