I need to parse the output of vol command only to get the id i.e only abcd-1234, that is being used in QProcess. Here is my code to get the Volume Serial Number:
QProcess process;
process.start("cmd /c vol C:");
process.waitForFinished(-1);
QByteArray out = process.readAllStandardOutput();
qDebug() << out;
Help me, thanks...
You can use the regular expression with QRegExp (http://qt-project.org/doc/qt-4.8/qregexp.html) to find the ID.
The vol command will always return the same message. So, you can read the result line by line and search the matching line:
QRegExp rx( "The Volume Serial Number is (.+)\\."); // Match the line with the ID and store it.
if ( rx.exactMatch( line ) {
QString id = rx.capturedTexts(1); // The first elt is the entire matching text.
qDebug() << id;
}
Related
I'm trying to get into the fascinating world of Common Lisp embedded in C++. My problem is that I can't manage to read and print from c++ a string returned by a lisp function defined in ECL.
In C++ I have this function to run arbitrary Lisp expressions:
cl_object lisp(const std::string & call) {
return cl_safe_eval(c_string_to_object(call.c_str()), Cnil, Cnil);
}
I can do it with a number in this way:
ECL:
(defun return-a-number () 5.2)
read and print in C++:
auto x = ecl_to_float(lisp("(return-a-number)"));
std::cout << "The number is " << x << std::endl;
Everything is set and works fine, but I don't know to do it with a string instead of a number. This is what I have tried:
ECL:
(defun return-a-string () "Hello")
C++:
cl_object y = lisp("(return-a-string)");
std::cout << "A string: " << y << std::endl;
And the result of printing the string is this:
A string: 0x3188b00
that I guess is the address of the string.
Here it is a capture of the debugger and the contents of the y cl_object. y->string.self type is an ecl_character.
Debug
(Starting from #coredump's answer that the string.self field provides the result.)
The string.self field is defined as type ecl_character* (ecl/object.h), which appears to be given in ecl/config.h as type int (although I suspect this is slightly platform dependent). Therefore, you will not be able to just print it as if it was a character array.
The way I found worked for me was to reinterpret it as a wchar_t (i.e. a unicode character). Unfortunately, I'm reasonably sure this isn't portable and depends both on how ecl is configured and the C++ compiler.
// basic check that this should work
static_assert(sizeof(ecl_character)==sizeof(wchar_t),"sizes must be the same");
std::wcout << "A string: " << reinterpret_cast<wchar_t*>(y->string.self) << std::endl;
// prints hello, as required
// note the use of wcout
The alternative is to use the lisp type base-string which does use char (base-char in lisp) as its character type. The lisp code then reads
(defun return-a-base-string ()
(coerce "Hello" 'base-string))
(there may be more elegant ways to do the conversion to base-string but I don't know them).
To print in C++
cl_object y2 = lisp("(return-a-base-string)");
std::cout << "Another: " << y2->base_string.self << std::endl;
(note that you can't mix wcout and cout in the same program)
According to section 2.6 Strings of The ECL Manual, I think that the actual character array is found by accessing the string.self field of the returned object. Can you try the following?
std::cout << y->string.self << std::endl;
std::string str {""};
cl_object y2 = lisp("(return-a-base-string)");
//get dimension
int j = y2->string.dim;
//get pointer
ecl_character* selv = y2->string.self;
//do simple pointer addition
for(int i=0;i<j;i++){
str += (*(selv+i));
}
//do whatever you want to str
this code works when the string is build from ecl_characters
from the documentation:
"ECL defines two C types to hold its characters: ecl_base_char and ecl_character.
When ECL is built without Unicode, they both coincide and typically match unsigned char, to cover the 256 codes that are needed.
When ECL is built with Unicode, the two types are no longer equivalent, with ecl_character being larger.
For your code to be portable and future proof, use both types to really express what you intend to do."
On my system the return-a-base-string is not needed, but I think it could be good to add for compatibility. I use the (ecl) embedded CLISP 16.1.2 version.
The following piece of code reads a string from lisp and converts to C++ strings types - std::string and c-string- and store them on C++ variables:
// strings initializations: string and c-string
std::string str2 {""};
char str_c[99] = " ";
// text read from clisp, whatever clisp function that returns string type
cl_object cl_text = lisp("(coerce (text-from-lisp X) 'base-string)");
//cl_object cl_text = lisp("(text-from-lisp X)"); // no base string conversions
// catch dimension
int cl_text_dim = cl_text->string.dim;
// complete c-string char by char
for(int ind=0;i<cl_text_dim;i++){
str_c[i] = ecl_char(cl_text,i); // ecl function to get char from cl_object
}
str_c[cl_text_dim] ='\0'; // end of the c-string
str2 = str_c; // get the string on the other string type
std::cout << "Dim: " << cl_ text_dim << " C-String var: " << str_c() << " String var << str2 << std::endl;
It is a slow process as passing char by char but it is the only way by the moment I know. Hope it helps. Greetings!
I have a QByteArray i create manually:
QByteArray hexArray(QByteArray::fromHex("495676"));
If this was encoded ASCII it would be "IVv".
If I want to get a single byte of data from that array.
I can do that like this:
qDebug() << messageToBeSent_raw[0];
However, that outputs I, which is correct but I would like to get 49. What I'm looking for is an equivalent of the QByteArray::toHex() just for a single byte. Is there a way to do it?
You can use QString::number.
qDebug() << QString::number(hexArray[0], 16);
How can i find a specific character in a QFile which has a text in it?
for example i have ' $5000 ' written somewhere in my file. in want to find the "$" sign so i will realize that I've reached the number.
I tried using QString QTextStream::read(qint64 maxlen) by putting 1 as the maxlen :
QFile myfile("myfile.txt");
myfile.open(QIODevice::ReadWrite | QIODevice::Text);
QTextStream myfile_stream(&myfile);
while(! myfile_stream.atEnd())
{
if( myfile_stream.read(1) == '$')
{
qDebug()<<"found";
break;
}
}
and i get "error: invalid conversion from 'char' to 'const char* "
i also tried using the operator[] but apparently it can't be used for files.
Read in a line at a time and search the text that you've read in
QTextStream stream(&myFile);
QString line;
do
{
line = stream.readLine();
if(line.contains("$"))
{
qDebug()<<"found";
break;
}
} while (!line.isNull());
The error message you've posted doesn't match the issue in your code. Possibly the error was caused by something else.
QTextStream::read returns QString. You can't compare QString and const char* directly, but operator[] can help:
QString s = stream.read(1);
if (s.count() == 1) {
if (s[0] == '$') {
//...
}
}
However reading a file by too small pieces will be very slow. If your file is small enough, you can read it all at once:
QString s = stream.readAll();
int index = s.indexOf('$');
If your file is large, it's better to read file by small chunks (1024 bytes for example) and calculate the index of found character using indexOf result and count of already read chunks.
a single char could be read with
QTextStream myfile_stream(&myfile);
QChar c;
while (!myfile_stream.atEnd())
myfile_stream >> c;
if (c == '$') {
...
}
myfile_stream.read(1) - this is not good practice, you should not read from file one byte at a time. Either read the entire file, or buffered/line by line if there is a risk for the file to be too big to fit in memory.
The error you get is because you compare a QString for equality with a character literal - needless to say that is not going to work as expected. A string is a string even if there is only one character in it. As advised - use either the [] operator or better off for reading - QString::at() const which is guaranteed to create no extra copy. You don't use it on the QFile, nor on the QTextStream, but on the QString that is returned from the read() method of the text stream targeted at the file.
Once you have the text in memory, you can either use the regular QString methods like indexOf() to search for the index of a contained character.
in want to find the "$" sign so i will realize that I've reached the
number.
It sounds to me that you're searching for the '$' symbol because you're more interested in the dollar value that follows it. In this case, I suggest reading the files line by line and running them through a QRegExp to extract any values you're looking for.
QRegExp dollarFind("\\$(\\d+)");
while(!myfile_stream.atEnd()){
QString line = myfile_stream.readLine();
if (dollarFind.exactMatch(line)){
QStringList dollars = dollarFind.capturedTexts();
qDebug() << "Dollar values found: " << dollars.join(", ");
}
}
hi a have a function that reads from a text file line by line each line I do some operations on it substitute a string..etc
then I push_back that line into a vector
this is my class in Parser.h
class Parser
{// start class
public:
vector<const char*> patterns;
Parser();
~Parser();
void RuleParser(const char *TextFileName); // this is the function that takes the file name
private:
};// end class
segment from function RuleParser
std::ifstream ifs(TextFileName);
while (!ifs.eof())
{
.
.modification code
.
patterns.push_back((buildString).c_str()); //buildString is the modified line
cout << buildString << endl;
}
but when I try to check out if the data in the vector is correct it output totally different data.
I even put a cout after the push_back to check it's integrty but I found buildString is correct... thats the data each time being pushed ... what I am doing wrong.
here is the loop I use to see if my data correct.
for (int i = 0;i < patterns.size() ;i++)
{
cout << patterns.at(i) << endl;
}
Well patterns is the collection of pointers so you end up push_back'ing a pointer to the same buildString in each iteration of the loop, instead of push_back'ing the string contents. Then when buildString changes in next iteration of the loop, the pointer becomes invalid but it still remains in patterns - not good
I suggest you declare patterns as:
vector<std::string> patterns;
This way when you do:
patterns.push_back(buildString.c_str())
the contents of the string will be copied instead of the pointer, and remain valid througout.
I have some problems combining the processing results I recieve from several Threads. And I'm not sure, if I use openmp correctly. The below code extract shows the openmp portion of my code.
Parameters:
thread private:
it: map iterator (timestamp, userkey)
ite: map iterator ((timestamp,userkey)/int amount)
thread_result_map: typedef map < userkey(str),timestamp(str) >
when, who: matching regex (timestamp, userkey)
shared among threads:
log: char array
size: log.size()
identifier, timestamp, userkey: boost::regex patterns
combined_result_map: typedef map < thread_result_map, hits(int) >
#pragma omp parallel shared(log, size, identifier, timestamp, userkey) private(it, ite, str_time, str_key, vec_str_result, i, id, str_current, when, who, thread_result_map)
{
#pragma omp for
for (i = 0 ; i < size ; i++){
str_current.push_back(log[i]);
if (log[i] == '\n') {
if (boost::regex_search(str_current, identifier)){
boost::regex_search(str_current, when, timestamp);
str_time = when[0];
boost::regex_search(str_current, who, userkey);
str_key = who[0];
thread_result_map.insert(make_pair(str_time, str_key));
}
str_current = ""; //reset temp string
}
}
#pragma omp critical
{
for (it=thread_result_map.begin(); it!=thread_result_map.end(); it++) {
id = omp_get_thread_num();
cout << thread_result_map[it->first] <<
thread_result_map[it->second];
cout << "tID_" << id << " reducing" << endl;
}
}
}
As you can see every thread has his own partition of the char array, it parses line by line from the array and if the current string is identified by "identifier", the timestamp and userkey are added to the thread's private result map (string/string).
Now after the loop I have several thread's private result maps. The combined_result_map is a map inside a map. The key is the combination of key/value of the threads result and the value is the amount of occurences of this combination.
I'm parsing only a portion of the timestamp so when in 1 hour the same userkey appears multiple times the hit counter will be increased.
The result should look something like this:
TIME(MMM/DD/HH/);USERKEY;HITS
May/25/13;SOMEKEY124345;3
So I have no problems combining hit amounts in the critical section (which I removed) by specifying combined+=results.
But how can I combine my result maps the same way? I know I have to iterate through threads maps, but when I put a "cout" inside the loop for testing every thread calls it only once.
A test run on my local syslog gives me the following output when I set all the regex to "error" (to make sure every identified line will have a userkey and a timestamp with the same name):
Pattern for parsing Access String:
error Pattern for parsing Timestamp:
error Pattern for parsing Userkey:
error
*** Parsing File /var/log/syslog
errortID_0 reducing errortID_1
reducing errortID_2 reducing
errortID_3 reducing
*** Ok! ________________ hits :
418 worktime: 0.0253871s
(The calculated hits come from thread private counters, that I removed in the code above)
So every of my 4 threads does a single cout and leaves the loop, although all together should have 418 hits. So what do I do wrong? How do I iterate through my results from inside my openmp area?
Found the problem myself, sorry for asking stupid questions.
I was trying to add the same key multiple times, that's why map size didn't increase and every thread looped only once.
Edit:
If anybody is interested in the solution how to combine thread results, this is how I did it. perhaps you see anything that could be improved.
I just changed the local threads result map to a vector of pairs(str,str).
This is the full working openmp code section. Pehaps it's useful for anyone:
#pragma omp parallel shared(log, size, identifier, timestamp, userkey) private(it, ite, str_time, str_key, i, id, str_current, when, who, local_res)
{
#pragma omp for
for (i = 0 ; i < size ; i++){
str_current.push_back(log[i]);
if (log[i] == '\n') { // if char is newline character
if (boost::regex_search(str_current, identifier)){ // if current line is access string
boost::regex_search(str_current, when, timestamp); // get timestamp from string
str_time = when[0];
boost::regex_search(str_current, who, userkey); // get userkey from string
str_key = who[0];
local_res.push_back((make_pair(str_time, str_key))); // append key-value-pair(timestamp/userkey)
id = omp_get_thread_num();
//cout << "tID_" << id << " - adding pair - my local result map size is now: " << local_res.size() << endl;
}
str_current = "";
}
}
#pragma omp critical
{
id = omp_get_thread_num();
hits += local_res.size();
cout << "tID_" << id << " had HITS: " << local_res.size() << endl;
for (i = 0; i < local_res.size(); i++) {
acc_key = local_res[i].second;
acc_time = local_res[i].first;
if(m_KeyDatesHits.count(acc_key) == 0) { // if there are no items for this key yet, make a new entry
m_KeyDatesHits.insert(make_pair(acc_key, str_int_MapType()));
}
if (m_KeyDatesHits[acc_key].count(acc_time) == 0) { // "acc_time" is a key value, if it doesn't exist yet, add it and set "1" as value
m_KeyDatesHits[acc_key].insert(make_pair(acc_time, 1 ));
it = m_KeyDatesHits.begin(); // iterator for userkeys/maps
ite = m_KeyDatesHits[acc_key].begin(); // iterator for times/clicks
} else m_KeyDatesHits[acc_key][acc_time]++; // if userkey already exist and timestamp already exists, count hits +1 for it
}
}
}
I did some tests and it's really running fast.
Using 4 Threads this searches a 150MB LogFile for access events, parses a custom user key and date from every event and combines the results in under 4 seconds.
At the End it creates a export list. This is the program output:
HELLO, welcome to LogMap 0.1!
C++/OpenMP Memory Map Parsing Engine
__________________ Number of processors available = 4
Number of threads = 4
Pattern for parsing Access String:
GET /_openbooknow/key/ Pattern for
parsing Timestamp: \d{2}/\w{3}/\d{4}
Pattern for parsing Userkey:
[a-zA-Z0-9]{20,32}
* Parsing File
/home/c0d31n/Desktop/access_log-test.txt
HITS: 169147 HITS: 169146 HITS: 169146
HITS: 169147
* Ok! ________ hits :
676586 worktime: 4.03816s
* new export file created: "./test.csv"
root#c0d3b0x:~/workspace/OpenBookMap/Release#
cat test.csv
"1nDh0gV6eE3MzK0517aE6VIU0";"28/Mar/2011";"18813"
"215VIU1wBN2O2Fmd63MVmv6QTZy";"28/Mar/2011";"6272"
"36Pu0A2Wly3uYeIPZ4YPAuBy";"18/Mar/2011";"18816"
"36Pu0A2Wly3uYeIPZ4YPAuBy";"21/Mar/2011";"12544"
"36Pu0A2Wly3uYeIPZ4YPAuBy";"22/Mar/2011";"12544"
"36Pu0A2Wly3uYeIPZ4YPAuBy";"23/Mar/2011";"18816"
"9E1608JFGk2GZQ4ppe1Grtv2";"28/Mar/2011";"12544"
"pachCsiog05bpK0kDA3K2lhEY";"17/Mar/2011";"18029"
"pachCsiog05bpK0kDA3K2lhEY";"18/Mar/2011";"12544"
"pachCsiog05bpK0kDA3K2lhEY";"21/Mar/2011";"18816"
"pachCsiog05bpK0kDA3K2lhEY";"22/Mar/2011";"6272"
"pachCsiog05bpK0kDA3K2lhEY";"23/Mar/2011";"18816"
"pachCsiog05bpK0kDA3K2lhEY";"28/Mar/2011";"501760"
"1nDh0gV6eE3MzK0517aE6VIU0";"28/Mar/2011";"18813"
"215VIU1wBN2O2Fmd63MVmv6QTZy";"28/Mar/2011";"6272"
"36Pu0A2Wly3uYeIPZ4YPAuBy";"18/Mar/2011";"18816"
"36Pu0A2Wly3uYeIPZ4YPAuBy";"21/Mar/2011";"12544"
"36Pu0A2Wly3uYeIPZ4YPAuBy";"22/Mar/2011";"12544"
"36Pu0A2Wly3uYeIPZ4YPAuBy";"23/Mar/2011";"18816"
"9E1608JFGk2GZQ4ppe1Grtv2";"28/Mar/2011";"12544"
"pachCsiog05bpK0kDA3K2lhEY";"17/Mar/2011";"18029"
"pachCsiog05bpK0kDA3K2lhEY";"18/Mar/2011";"12544"
"pachCsiog05bpK0kDA3K2lhEY";"21/Mar/2011";"18816"
"pachCsiog05bpK0kDA3K2lhEY";"22/Mar/2011";"6272"
"pachCsiog05bpK0kDA3K2lhEY";"23/Mar/2011";"18816"
"pachCsiog05bpK0kDA3K2lhEY";"28/Mar/2011";"501760"