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Solved
using std::stringstream to print a string in hex decimal form
Posted on 2013-12-08
I am using a log4cpp to log any debug info to a file.
log4cpp::Category::getRoot
There is time I would like to turn the error string into an array of hex codes for each character in the string
log4cpp::Category::getRoot
What is the best way to transform "My error string" to "0x65 0x63 0x67 0x68 .. .. .."
log4cpp::Category::getRoot
There is time I would like to turn the error string into an array of hex codes for each character in the string
log4cpp::Category::getRoot
What is the best way to transform "My error string" to "0x65 0x63 0x67 0x68 .. .. .."
[X]
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8 Comments
Active 1 day ago
you could use std::ostringstream and iomanip:
Sara
#include <sstream>
#include <iomanip>
...
std::ostringstream oss;
for (int n = 0; n < (int)input_string; ++n)
{
oss << "0x" << std::hex << std::right << std::setw(2) << std::setfill('0')
<< (int)input_string[n] << ' ';
}
Sara
'<algorithm>' has a few neat helpers to make that simpler, e.g.
#include <string>
#include <sstream>
#include <algorithm>
#include <iostream>
#include <iomanip>
using namespace std;
template<class T> struct hexify {
hexify(stringstream& out) : ss(out) {}
void operator() (T& x) { ss << setbase(16) << "0x" << (int) x << ' ';}
stringstream& ss;
};
template<class T>
ostream& operator<<(ostream& os, const hexify<T>& h) { os << h.ss.str(); return os;}
int main() {
string s = "My error message";
stringstream ss;
cout << for_each(s.begin(), s.end(), hexify<char>(ss)) << endl;
// Or, as in your case:
//
// log4cpp::Category::getRoot() << log4cpp::Priority::DEBUG << for_each(s.begin(), s.end(), hexify<char>(ss)) << endl;
return 0;
}
JKR,
I really like your new trick, as I am learning to apply generic programming. (template).
One more winkle I like to add, what if I would like to print max16 Hex numbers in a row.
how would I do it.
I really like your new trick, as I am learning to apply generic programming. (template).
One more winkle I like to add, what if I would like to print max16 Hex numbers in a row.
how would I do it.
You mean like adding a line break after 16 characters? E.g like
#include <string>
#include <sstream>
#include <algorithm>
#include <iostream>
#include <iomanip>
using namespace std;
template<class T> struct hexify {
hexify(stringstream& out) : ss(out), count(0) {}
void operator() (T& x) { ss << setbase(16) << "0x" << (int) x << ' '; if(!((count +1 ) % 16)) ss << endl; ++count;}
stringstream& ss;
unsigned int count;
};
template<class T>
ostream& operator<<(ostream& os, const hexify<T>& h) { os << h.ss.str(); return os;}
int main() {
string s = "My error message My error message My error message My error message";
stringstream ss;
cout << for_each(s.begin(), s.end(), hexify<char>(ss)) << endl;
// Or, as in your case:
//
// log4cpp::Category::getRoot() << log4cpp::Priority::DEBUG << for_each(s.begin(), s.end(), hexify<char>(ss)) << endl;
return 0;
}
JKR,
I forget to mention if what I am trying to print out is an array of char (e.g. TCP/IP) packet, '\n' can be present in the char array, I would like to print '\n' as ASCII code and still able to print 16 maximum HEX number in a row.
So I suppose I can not use string or stringstream am I right
I forget to mention if what I am trying to print out is an array of char (e.g. TCP/IP) packet, '\n' can be present in the char array, I would like to print '\n' as ASCII code and still able to print 16 maximum HEX number in a row.
So I suppose I can not use string or stringstream am I right
The above should take care of it ;o)
Edit: *Will* definitely take care of it:
Edit: *Will* definitely take care of it:
#include <string>
#include <sstream>
#include <algorithm>
#include <iostream>
#include <iomanip>
using namespace std;
template<class T> struct hexify {
hexify(stringstream& out) : ss(out), count(0) {}
void operator() (T& x) { ss << setbase(16) << "0x" << (int) x << ' '; if(!((count +1 ) % 16)) ss << endl; ++count;}
stringstream& ss;
unsigned int count;
};
template<class T>
ostream& operator<<(ostream& os, const hexify<T>& h) { os << h.ss.str(); return os;}
int main() {
string s = "My error message\n My error message\n My error message\n My error message";
stringstream ss;
cout << for_each(s.begin(), s.end(), hexify<char>(ss)) << endl;
// Or, as in your case:
//
// log4cpp::Category::getRoot() << log4cpp::Priority::DEBUG << for_each(s.begin(), s.end(), hexify<char>(ss)) << endl;
return 0;
}
Active 1 day ago
if you want display a string buffer like a hex editor does which shows the hex values in a table at the left side and the printable characters for each row at the right side
you could advance and improve the functor jkr has shown by
note, the code doesn't use template classes as it is specialized for char type only anyhow. it also doesn't require to pass a stringstream object but uses an own temporary.
Sara
| 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 |
-----|-------------------------------------------------|-----------------
0000 | 48 65 6c 6c 6f 20 57 6f 72 6c 64 21 20 0a 49 20 | Hello World! .I
0016 | 61 6d 20 68 65 72 65 2e 20 57 68 65 72 65 20 61 | am here. Where a
0032 | 72 65 20 79 6f 75 3f 0a 00 00 00 00 00 00 00 00 | re you?.
you could advance and improve the functor jkr has shown by
struct hexedit
{
std::string srow;
int nrows;
std::ostringstream & get_oss()
{
static std::ostringstream oss;
return oss;
}
hexedit() : nrows(0)
{
get_oss() = std::ostringstream();
get_oss() << " | 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 |" << std::endl
<< "-----|-------------------------------------------------|-----------------" << std::endl
<< "0000 | ";
}
~hexedit()
{
if (srow.empty() == false)
{
this->operator()('\0', true);
}
}
void operator() (char c, bool bend = false)
{
if (bend == true)
{
std::string send = "00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | ";
send = send.substr(srow.length()*3);
get_oss() << send << srow << std::endl;
return;
}
if (srow.length() == 16)
{
get_oss() << "| " << srow << std::endl << std::dec << std::right << std::setw(4) << std::setfill('0') << (++nrows)*16 << " | ";
srow = "";
}
get_oss() << std::hex << std::setw(2) << std::right << std::setfill('0') << (int) c << ' ';
srow += (isprint(c) == 0)? '.' : c;
}
};
std::ostream& operator<<(std::ostream& os, hexedit& he)
{
os << he.get_oss().str();
return os;
}
int main()
{
std::string s = "Hello World! \nI am here. Where are you?\n";
std::cout << std::for_each(s.begin(), s.end(), hexedit()) << std::endl;
s = "0123456789012345";
std::cout << std::for_each(s.begin(), s.end(), hexedit()) << std::endl;
return 0;
}
note, the code doesn't use template classes as it is specialized for char type only anyhow. it also doesn't require to pass a stringstream object but uses an own temporary.
Sara
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