I read an answer here showing how to read an entire stream into a std::string with the following one (two) liner:
std::istreambuf_iterator<char> eos;
std::string s(std::istreambuf_iterator<char>(stream), eos);
For doing something similar to read a binary stream into a std::vector
, why can't I simply replace char
with uint8_t
and std::string
with std::vector
?
auto stream = std::ifstream(path, std::ios::in | std::ios::binary);
auto eos = std::istreambuf_iterator<uint8_t>();
auto buffer = std::vector<uint8_t>(std::istreambuf_iterator<uint8_t>(stream), eos);
The above produces a compiler error (VC2013):
1>d:\non-svn\c++\library\i\file\filereader.cpp(62): error C2440: '' : cannot convert from 'std::basic_ifstream>' to 'std::istreambuf_iterator>' 1>
with 1> [ 1> _Elem=uint8_t 1> ] 1>
No constructor could take the source type, or constructor overload resolution was ambiguous
There's just a type mismatch. ifstream
is just a typedef:
typedef basic_ifstream<char> ifstream;
So if you want to use a different underlying type, you just have to tell it:
std::basic_ifstream<uint8_t> stream(path, std::ios::in | std::ios::binary);
auto eos = std::istreambuf_iterator<uint8_t>();
auto buffer = std::vector<uint8_t>(std::istreambuf_iterator<uint8_t>(stream), eos);
That works for me.
Or, since Dietmar says this might be a little sketchy, you could do something like:
auto stream = std::ifstream(...);
std::vector<uint8_t> data;
std::for_each(std::istreambuf_iterator<char>(stream),
std::istreambuf_iterator<char>(),
[&data](const char c){
data.push_back(c);
});