I am working on a pet project with the libsodium library, and found that converting unsigned char * to char * was less straight forward than I imagined. Also I first was confused because the tests were passing in Release mode and only bit later I realised they were not passing in Debug mode. So I came up with the following:
std::string string_from_uchar(const unsigned char * c, unsigned long long lc)
{
unsigned char * cc = new unsigned char[lc+1] ;
std::strncpy((char *) cc, (char *) c, lc);
cc[lc] = 0;
char* cr = reinterpret_cast<char *> (cc);
std::string ret(cr);
delete[](cr);
return ret;
}
While it now passed the tests, I was be grateful if someone could check if it is the right way of doing it (for instance would that work on another environment like gcc or clang?).
You're massively over-thinking this.
The copy is redundant, as is the extra dynamic allocation and the addition of a null terminator (because std::string has a constructor that accepts a length argument for just this sort of occasion).
The various char can be aliased, so simply:
std::string string_from_uchar(const unsigned char * c, unsigned long long lc)
{
return std::string((const char*)c, lc);
}
In fact, if you use the constructor that takes a range, you don't even need the cast:
std::string string_from_uchar(const unsigned char * c, unsigned long long lc)
{
return std::string(c, c + lc);
}
It barely even warrants being in its own function.
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