Okay, sleeves rolled up: let's look at C++ version:
- Don't use C strings unless you need to (sprintf to build a two-char string is not... very efficient)
- Use iostreams to encode/decode the hex digits (
std::hex
) - The
hex2bin
could optimized, but I went for "simpler" - I added a modicum of input sanitizing on
hex2bin
#include <string>
#include <sstream>
#include <iomanip>
std::string bin2hex(std::string const &s) {
std::ostringstream oss;
for (unsigned char ch : s)
oss << std::hex << std::setw(2) << std::setfill('0') << (int) ch;
return oss.str();
}
#include <cassert>
std::string hex2bin(std::string const& s) {
assert(s.length() % 2 == 0);
std::string sOut;
sOut.reserve(s.length()/2);
std::string extract;
for (std::string::const_iterator pos = s.begin(); pos<s.end(); pos += 2)
{
extract.assign(pos, pos+2);
sOut.push_back(std::stoi(extract, nullptr, 16));
}
return sOut;
}
#include <iostream>
int main() {
std::cout << "ENCODED: " << bin2hex("This is a 123 test.") << "\n";
std::cout << "DECODED: " << hex2bin(bin2hex("This is a 123 test.")) << "\n";
}
Output:
ENCODED: 5468697320697320612031323320746573742e
DECODED: This is a 123 test.