Converting a hex string to a byte array

by

This ought to work:

int char2int(char input)
{
  if(input >= '0' && input <= '9')
    return input - '0';
  if(input >= 'A' && input <= 'F')
    return input - 'A' + 10;
  if(input >= 'a' && input <= 'f')
    return input - 'a' + 10;
  throw std::invalid_argument("Invalid input string");
}

// This function assumes src to be a zero terminated sanitized string with
// an even number of [0-9a-f] characters, and target to be sufficiently large
void hex2bin(const char* src, char* target)
{
  while(*src && src[1])
  {
    *(target++) = char2int(*src)*16 + char2int(src[1]);
    src += 2;
  }
}

Depending on your specific platform there’s probably also a standard implementation though.

More Related Contents:

  1. C++ convert string to hexadecimal and vice versa
  2. How to assign string pointer value to elements of a vector using loops in C++
  3. c++ removing whitespace fails by using iterators
  4. Easiest way to convert int to string in C++
  5. How to convert a std::string to const char* or char*
  6. C++ convert hex string to signed integer
  7. How do I iterate over cin line by line in C++?
  8. Converting std::__cxx11::string to std::string
  9. Is a string literal in С++ created in static memory?
  10. Will std::string always be null-terminated in C++11?
  11. What’s the rationale for null terminated strings?
  12. Sizeof string literal
  13. stringstream, string, and char* conversion confusion
  14. How to compare multiple strings inside an if statement?
  15. How to implode a vector of strings into a string (the elegant way)
  16. Fast String Hashing Algorithm with low collision rates with 32 bit integer [closed]
  17. Convert a string to a date in C++
  18. std::strings’s capacity(), reserve() & resize() functions
  19. splitting a string into an array in C++ without using vector
  20. Most optimized way of concatenation in strings
  21. How do I print the full value of a long string in gdb?
  22. comparison between string literal
  23. How can I make the map::find operation case insensitive?
  24. Convert std::string to QString
  25. How do you validate that a string is a valid IPv4 address in C++?
  26. “to_string” isn’t a member of “std”?
  27. Reverse String C++ using char array
  28. Why does std::string not provide a conversion to const char*?
  29. C++ – repeatedly using istringstream
  30. Get bytes from std::string in C++

Leave a Comment