1 files changed, 40 insertions, 0 deletions
diff --git a/helper.cpp b/helper.cpp
index 116efa5..baaacbb 100644
--- a/helper.cpp
+++ b/helper.cpp
@@ -7,6 +7,14 @@
 
 #include <QString>
 #include <QByteArray>
+#include <QFileInfo>
+#include <QFile>
+
+#define CRYPTOPP_ENABLE_NAMESPACE_WEAK 1
+#include <md5.h>
+#include <files.h>
+#include <filters.h>
+#include <hex.h>
 
 #include "helper.h"
 
@@ -35,5 +43,37 @@ namespace Helper {
 			return retval;
 		}
 	}
+
+	const QString md5Sum(const QString &path){
+		QFileInfo info(path);
+		if(!info.exists() || !info.isFile()){
+			return QString();
+		}
+
+		using namespace CryptoPP;
+		Weak::MD5 hash;
+		std::string res;
+		QString retval;
+		if(info.size() < (5 * 1024 * 1024)){
+			FileSource f(qPrintable(path), true, new HashFilter(hash, new HexEncoder(new StringSink(res))));
+			retval = QString::fromStdString(res).toLower();
+		}else{
+			QFile file(path);
+			file.open(QIODevice::ReadOnly);
+			int offset = info.size() / 3;
+			file.seek(offset);
+			int numBytes = 512 * 1024;
+			char *data = new char[numBytes];
+			int read = file.read(data, numBytes);
+			if(read != numBytes){
+				delete [] data;
+				return QString();
+			}
+			StringSource s((byte*)data, numBytes, true, new HashFilter(hash, new HexEncoder(new StringSink(res))));
+			retval = QString::fromStdString(res).toLower();
+			delete [] data;
+		}
+		return retval;
+	}
 }