CODEWITHSUNDEEP
c++stringqtbyte
goldfrapp04
goldfrapp04

Reputation: 2356

Binary string to byte[] in C++?

I'm using QString in Qt actually. So if there's a straightforward function please tell me:)

What I'm thinking of doing is storing a binary string into a file byte by byte:

QString code = "0110010101010100111010 /*...still lots of 0s & 1s here..*/";
ofstream out(/*...init the out file here...*/);
for(; code.length() / 8 > 0; code.remove(0, 8))    //a byte is 8 bits
{
    BYTE b = QStringToByte(/*...the first 8 bits of the code left...*/);
    out.write((char *)(&b), 1);
}
/*...deal with the rest less than 8 bits here...*/

How should I write my QStringToByte() function?

BYTE QStringToByte(QString s)    //s is 8 bits
{
    //?????
}

Thank you for your reply.

Upvotes: 1

Views: 1858

Answers (2)

01100110
01100110

Reputation: 2344

You may try boost::dynamic_bitset to write bits to a file.

void write_to_file( std::ofstream& fp, const boost::dynamic_bitset<boost::uint8_t>& bits )
{
     std::ostream_iterator<boost::uint8_t> osit(fp);
     boost::to_block_range(bits, osit);
}

Upvotes: 0

Kornel Kisielewicz
Kornel Kisielewicz

Reputation: 57555

QString has a nice toInt method, that optionally takes the base as a parameter (in your case base 2). Just strip 8 characters to form a new QString, and do str.toInt( &somebool, 2 ).

With no error checking it would be probably:

BYTE QStringToByte(QString s)    //s is 8 bits
{
  bool ok;
  return (BYTE)(s.left( 8 ).toInt( &ok, 2 ));
}

(don't take my word for it though, never wrote a line in Qt in my life)

Upvotes: 1

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