A
andy
Ian said:
FWIW Below is my version of the comparison. Moving the construction of
the stringstream into the loop really kills performance of the
stringstream version. However this is IMO a more realistic *simple*
useage . I also modified the other code into C++ style but thats by the
way. With this approach the C code is an order of magnitude faster ( I
had to decrease the number of loops to avoid waiting on the
stringstream code), but its not really a fair comparison. The killer of
the C version for me is that you cant have arbitrary length tokens. You
are limited to whatever the value of ABRsize is. If the C coders want
to write a version that can handle arbitrary length C style strings
then it would be a fairer comparison IMO, (though my previous comments
re ease of coding, testing etc remain) BTW I used boost timer for
timing. If you havent got the boost distro you will just have to modify
those parts. I'm too lazy to do that...
regards
Andy Little
#include <sstream>
#include <string>
#include <vector>
#include <iostream>
#include <boost/timer.hpp>
int const ABRsize = 64;
int const NLOOPS = 100000;
const char *
toksplit(
const char *src,
char tokchar,
char *token,
size_t lgh
);
int main()
{
char tst[] = "this\nis\n\nan\nempty\n\n\nline";
std::cout << "Timing stringstream version: ";
boost::timer t0;
for( int count = 0; count < NLOOPS; ++count) {
std::stringstream ss;
ss << tst;
while (! ss.eof() ){
std::string str;
getline(ss,str,'\n');
}
}
std::cout << t0.elapsed() << "s\n";
std::cout << "Timing toksplit version: ";
boost::timer t1;
for( int count =0;count < NLOOPS;++count){
char token[ABRsize + 1];
const char *t = tst;
while (*t) {
t = toksplit(t, '\n', token, ABRsize);
}
}
std::cout << t1.elapsed() << "s\n";
}
const char *toksplit(
const char *src, /* Source of tokens */
char tokchar, /* token delimiting char */
char *token, /* receiver of parsed token */
size_t lgh) /* length token can receive */
/* not including final '\0' */
{
if (src) {
while (' ' == *src) *src++;
while (*src && (tokchar != *src)) {
if (lgh) {
*token++ = *src;
--lgh;
}
src++;
}
if (*src && (tokchar == *src)) src++;
}
*token = '\0';
return src;
} /* toksplit */