c++ - What can I do with an unsigned char* when I needed a string? -

suppose have unsigned char*, let's call it: some_data

unsigned char* some_data; 

and some_data has url-like data in it. example:

"aasdasdassdfasdfasdf&foo=cow&asdfasasdfadsfdsafasd" 

i have function can grab value of 'foo' follows:

// looks value of 'foo' bool grabfoovalue(const std::string& p_string, std::string& p_foo_value) {     size_t start = p_string.find("foo="), end;     if(start == std::string::npos)         return false;      start += 4;     end = p_string.find_first_of("& ", start);      p_foo_value = p_string.substr(start, end - start);     return true; } 

the trouble need string pass function, or @ least char* (which can converted string no problem).

i can solve problem casting:

reinterpret_cast<char *>(some_data) 

and pass function okie-dokie

...

until used valgrind , found out can lead subtle memory leak.

conditional jump or move depends on uninitialised value(s)  __gi_strlen 

from gathered, has reinterpret casting messing null indicating end of string. when c++ tries figure out length of string thing's screwy.

given can't change fact some_data represented unsigned char*, there way go using grabfoovalue function without having these subtle problems?

i'd prefer keep value-finding function have, unless there better way rip foo-value out of (sometimes large) unsigned char*.

and despite unsigned char* some_data 's varying, , large size, can assume value of 'foo' somewhere on, thoughts try , char* of first x characters of unsigned char*. potentially rid of string-length issue having me set char* ends.

i tried using combination of strncpy , casting far no dice. thoughts?

you need know length of data unsigned char * points to, since isn't 0-terminated.

then, use e.g:

std::string s((char *) some_data, (char *) some_data + len);