text: #include "bitcoinaddressvalidator.h"
  
  /* Base58 characters are:
       "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz"
  
    This is:
    - All numbers except for '0'
    - All uppercase letters except for 'I' and 'O'
    - All lowercase letters except for 'l'
  
    User friendly Base58 input can map
    - 'l' and 'I' to '1'
    - '0' and 'O' to 'o'
  */
  
  BitcoinAddressValidator::BitcoinAddressValidator(QObject *parent) :
      QValidator(parent)
  {
  }
  
  QValidator::State BitcoinAddressValidator::validate(QString &input, int &pos) const
  {
      // Correction
      for(int idx=0; idx<input.size();)
      {
          bool removeChar = false;
          QChar ch = input.at(idx);
          // Corrections made are very conservative on purpose, to avoid
          // users unexpectedly getting away with typos that would normally
          // be detected, and thus sending to the wrong address.
          switch(ch.unicode())
          {
          // Qt categorizes these as "Other_Format" not "Separator_Space"
          case 0x200B: // ZERO WIDTH SPACE
          case 0xFEFF: // ZERO WIDTH NO-BREAK SPACE
              removeChar = true;
              break;
          default:
              break;
          }
          // Remove whitespace
          if(ch.isSpace())
              removeChar = true;
          // To next character
          if(removeChar)
              input.remove(idx, 1);
          else
              ++idx;
      }
  
      // Validation
      QValidator::State state = QValidator::Acceptable;
      for(int idx=0; idx<input.size(); ++idx)
      {
          int ch = input.at(idx).unicode();
  
          if(((ch >= '0' && ch<='9') ||
             (ch >= 'a' && ch<='z') ||
             (ch >= 'A' && ch<='Z')) &&
             ch != 'l' && ch != 'I' && ch != '0' && ch != 'O')
          {
              // Alphanumeric and not a 'forbidden' character
          }
          else
          {
              state = QValidator::Invalid;
          }
      }
  
      // Empty address is "intermediate" input
      if(input.isEmpty())
      {
          state = QValidator::Intermediate;
      }
  
      return state;
  }
  