Reading directly from an std::istream into an std::string

c++ stdstring iostream
Fire Lancer picture Fire Lancer · Nov 29, 2009 · Viewed 24.7k times · Source

Is there anyway to read a known number of bytes, directly into an std::string, without creating a temporary buffer to do so?

eg currently I can do it by

boost::uint16_t len;
is.read((char*)&len, 2);
char *tmpStr = new char[len];
is.read(tmpStr, len);
std::string str(tmpStr, len);
delete[] tmpStr;

Answer

GManNickG picture GManNickG · Nov 29, 2009

std::string has a resize function you could use, or a constructor that'll do the same:

boost::uint16_t len;
is.read((char*)&len, 2);

std::string str(len, '\0');
is.read(&str[0], len);

This is untested, and I don't know if strings are mandated to have contiguous storage.

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