base64.cpp

   1
   2 #include <QString>
   3 #include <QByteArray>
   4 #include <QDebug>
   5 #include <Qt>
   6
   7 static QString keystring = QString("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/");
   8
   9 QString toBase64(QByteArray binary) {
  10         QString retval;
  11         int i;
  12         int pad = binary.size() % 3;
  13         for(i = 0; i < binary.size(); i+=3) {
  14                 quint8 a = 0;
  15                 quint8 b = 0;
  16                 quint8 c = 0;
  17                 a = binary[i];
  18                 retval.append(keystring[(a & 0xfc) >> 2 ]);
  19                 if( i+1 < binary.size()) {
  20                         b = binary[i+1];
  21                         quint8 idex = ((a & 0x03) << 4) |  ((b & 0xf0) >> 4);
  22                         retval.append(keystring[idex]);
  23                         if (i+2 == binary.size()) {
  24                                 retval.append(keystring[(b & 0x0f) << 2]);
  25                         }
  26                 } else {
  27                         retval.append(keystring[(a & 0x03) << 4]);
  28                         break;
  29                 }
  30                 if( i+2 < binary.size()) {
  31                         c = binary[i+2];
  32                         quint8 idex = ((b & 0x0f) << 2) | ((c & 0xc0) >> 6);
  33                         retval.append(keystring[idex]);
  34                         retval.append(keystring[c & 0x3f]);
  35                 }
  36         }
  37         if(pad == 1)
  38                 retval.append("==");
  39         if(pad == 2)
  40                 retval.append("=");
  41         return retval;
  42 }
  43
  44 QByteArray fromBase64(QString text) {
  45         QByteArray retval;
  46         if( text.size() % 4 != 0)
  47                 return retval;
  48         for(int i = 0; i < text.size(); i+=4) {
  49                 quint8 idex1 = static_cast<quint8>(keystring.indexOf(text[i])); // Something between 0 and 63
  50                 quint8 idex2 = static_cast<quint8>(keystring.indexOf(text[i+1]));
  51                 quint8 idex3 = static_cast<quint8>(keystring.indexOf(text[i+2]));
  52                 quint8 idex4 = static_cast<quint8>(keystring.indexOf(text[i+3]));
  53                 retval.append( ((idex1 << 2) | ((idex2 & 0x30) >> 4))) ;
  54                 if(text[i+2] == '=')
  55                         return retval;
  56                 retval.append( ((idex2 & 0x0f) << 4) | ((idex3 & 0x3c) >> 2)  ) ;
  57                 if(text[i+3] == '=')
  58                         return retval;
  59                 retval.append( ((idex3 & 0x03) << 6) | (idex4)  ) ;
  60
  61         }
  62         return retval;
  63 }
  64
  65 /*
  66  * Yay, unit tests.
  67 int main(void) {
  68         QByteArray test = QByteArray("Texas!");
  69         qDebug() << test;
  70         qDebug() << toBase64(test);
  71         qDebug() << fromBase64(toBase64(test));
  72         return 0;
  73 }
  74 */