Performance problem with QFile.
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I'm trying to calculate the hash of some disk image files (.iso)
so i have to read the entire file and store it in QByteArray to pass it later to QCryptographicHash::Hash
the problem is with reading performance, it takes a lot of time and the system freeze while using QFile::readAll() and storing it in byte array.
is there any solution to reduce the time and prevent the system form freezing? -
Use the stream operators. QCryptographicHash has an API that works with streaming QIODevices, too.
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can you write a small piece of code :)
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Try like this:
@/max bytes to read at once/
static const qint64 CHUNK_SIZE = 4096;/init hash/
QCryptographicHash hash(Sha1);/open file/
QFile file("foo.bar");
if (!file.open(QIODevice::ReadOnly))
return;/process file contents/
QByteArray temp = file.read(CHUNK_SIZE);
while(!temp.isEmpty())
{
hash.addData(temp);
temp = file.read(CHUNK_SIZE);
}/finalize/
const QByteArray res = hash.result();
qDebug("Hash is: %s", res.toHex());@ -
thank you, now it works times better :)
