void main()
{
	Hashtable *table;
	table = new Hashtable(TABLESIZE);

	readFromFile(table, DATAPATH);
	//table->print();
	cout << "Fill Factor: " << table->getFillFactor() << "( " << table->getElementCount() << " / " << TABLESIZE << " )" << endl;
	cout << "Find: " << table->find("Lani")->text << endl;
	delete table;
}
Exemple #2
0
string
StringUtils::guessEncoding(unsigned char* bytes, int length, Hashtable const& hints) {
  Hashtable::const_iterator i = hints.find(DecodeHints::CHARACTER_SET);
  if (i != hints.end()) {
    return i->second;
  }
  // Does it start with the UTF-8 byte order mark? then guess it's UTF-8
  if (length > 3 &&
      bytes[0] == (unsigned char) 0xEF &&
      bytes[1] == (unsigned char) 0xBB &&
      bytes[2] == (unsigned char) 0xBF) {
    return UTF8;
  }
  // For now, merely tries to distinguish ISO-8859-1, UTF-8 and Shift_JIS,
  // which should be by far the most common encodings. ISO-8859-1
  // should not have bytes in the 0x80 - 0x9F range, while Shift_JIS
  // uses this as a first byte of a two-byte character. If we see this
  // followed by a valid second byte in Shift_JIS, assume it is Shift_JIS.
  // If we see something else in that second byte, we'll make the risky guess
  // that it's UTF-8.
  bool canBeISO88591 = true;
  bool canBeShiftJIS = true;
  bool canBeUTF8 = true;
  int utf8BytesLeft = 0;
  int maybeDoubleByteCount = 0;
  int maybeSingleByteKatakanaCount = 0;
  bool sawLatin1Supplement = false;
  bool sawUTF8Start = false;
  bool lastWasPossibleDoubleByteStart = false;

  for (int i = 0;
       i < length && (canBeISO88591 || canBeShiftJIS || canBeUTF8);
       i++) {

    int value = bytes[i] & 0xFF;

    // UTF-8 stuff
    if (value >= 0x80 && value <= 0xBF) {
      if (utf8BytesLeft > 0) {
        utf8BytesLeft--;
      }
    } else {
      if (utf8BytesLeft > 0) {
        canBeUTF8 = false;
      }
      if (value >= 0xC0 && value <= 0xFD) {
        sawUTF8Start = true;
        int valueCopy = value;
        while ((valueCopy & 0x40) != 0) {
          utf8BytesLeft++;
          valueCopy <<= 1;
        }
      }
    }

    // ISO-8859-1 stuff

    if ((value == 0xC2 || value == 0xC3) && i < length - 1) {
      // This is really a poor hack. The slightly more exotic characters people might want to put in
      // a QR Code, by which I mean the Latin-1 supplement characters (e.g. u-umlaut) have encodings
      // that start with 0xC2 followed by [0xA0,0xBF], or start with 0xC3 followed by [0x80,0xBF].
      int nextValue = bytes[i + 1] & 0xFF;
      if (nextValue <= 0xBF &&
          ((value == 0xC2 && nextValue >= 0xA0) || (value == 0xC3 && nextValue >= 0x80))) {
        sawLatin1Supplement = true;
      }
    }
    if (value >= 0x7F && value <= 0x9F) {
      canBeISO88591 = false;
    }

    // Shift_JIS stuff

    if (value >= 0xA1 && value <= 0xDF) {
      // count the number of characters that might be a Shift_JIS single-byte Katakana character
      if (!lastWasPossibleDoubleByteStart) {
        maybeSingleByteKatakanaCount++;
      }
    }
    if (!lastWasPossibleDoubleByteStart &&
        ((value >= 0xF0 && value <= 0xFF) || value == 0x80 || value == 0xA0)) {
      canBeShiftJIS = false;
    }
    if ((value >= 0x81 && value <= 0x9F) || (value >= 0xE0 && value <= 0xEF)) {
      // These start double-byte characters in Shift_JIS. Let's see if it's followed by a valid
      // second byte.
      if (lastWasPossibleDoubleByteStart) {
        // If we just checked this and the last byte for being a valid double-byte
        // char, don't check starting on this byte. If this and the last byte
        // formed a valid pair, then this shouldn't be checked to see if it starts
        // a double byte pair of course.
        lastWasPossibleDoubleByteStart = false;
      } else {
        // ... otherwise do check to see if this plus the next byte form a valid
        // double byte pair encoding a character.
        lastWasPossibleDoubleByteStart = true;
        if (i >= length - 1) {
          canBeShiftJIS = false;
        } else {
          int nextValue = bytes[i + 1] & 0xFF;
          if (nextValue < 0x40 || nextValue > 0xFC) {
            canBeShiftJIS = false;
          } else {
            maybeDoubleByteCount++;
          }
          // There is some conflicting information out there about which bytes can follow which in
          // double-byte Shift_JIS characters. The rule above seems to be the one that matches practice.
        }
      }
    } else {
      lastWasPossibleDoubleByteStart = false;
    }
  }
  if (utf8BytesLeft > 0) {
    canBeUTF8 = false;
  }

  // Easy -- if assuming Shift_JIS and no evidence it can't be, done
  if (canBeShiftJIS && ASSUME_SHIFT_JIS) {
    return SHIFT_JIS;
  }
  if (canBeUTF8 && sawUTF8Start) {
    return UTF8;
  }
  // Distinguishing Shift_JIS and ISO-8859-1 can be a little tough. The crude heuristic is:
  // - If we saw
  //   - at least 3 bytes that starts a double-byte value (bytes that are rare in ISO-8859-1), or
  //   - over 5% of bytes could be single-byte Katakana (also rare in ISO-8859-1),
  // - and, saw no sequences that are invalid in Shift_JIS, then we conclude Shift_JIS
  if (canBeShiftJIS && (maybeDoubleByteCount >= 3 || 20 * maybeSingleByteKatakanaCount > length)) {
    return SHIFT_JIS;
  }
  // Otherwise, we default to ISO-8859-1 unless we know it can't be
  if (!sawLatin1Supplement && canBeISO88591) {
    return ISO88591;
  }
  // Otherwise, we take a wild guess with platform encoding
  return PLATFORM_DEFAULT_ENCODING;
}
string
StringUtils::guessEncoding(char* bytes, int length,
                           Hashtable const& hints) {
    Hashtable::const_iterator i = hints.find(DecodeHints::CHARACTER_SET);
    if (i != hints.end()) {
        return i->second;
    }
    typedef bool boolean;
    // For now, merely tries to distinguish ISO-8859-1, UTF-8 and Shift_JIS,
    // which should be by far the most common encodings.
    boolean canBeISO88591 = true;
    boolean canBeShiftJIS = true;
    boolean canBeUTF8 = true;
    int utf8BytesLeft = 0;
    //int utf8LowChars = 0;
    int utf2BytesChars = 0;
    int utf3BytesChars = 0;
    int utf4BytesChars = 0;
    int sjisBytesLeft = 0;
    //int sjisLowChars = 0;
    int sjisKatakanaChars = 0;
    //int sjisDoubleBytesChars = 0;
    int sjisCurKatakanaWordLength = 0;
    int sjisCurDoubleBytesWordLength = 0;
    int sjisMaxKatakanaWordLength = 0;
    int sjisMaxDoubleBytesWordLength = 0;
    //int isoLowChars = 0;
    //int isoHighChars = 0;
    int isoHighOther = 0;

    typedef char byte;
    boolean utf8bom = length > 3 &&
                      bytes[0] == (byte) 0xEF &&
                      bytes[1] == (byte) 0xBB &&
                      bytes[2] == (byte) 0xBF;

    for (int i = 0;
            i < length && (canBeISO88591 || canBeShiftJIS || canBeUTF8);
            i++) {

        int value = bytes[i] & 0xFF;

        // UTF-8 stuff
        if (canBeUTF8) {
            if (utf8BytesLeft > 0) {
                if ((value & 0x80) == 0) {
                    canBeUTF8 = false;
                } else {
                    utf8BytesLeft--;
                }
            } else if ((value & 0x80) != 0) {
                if ((value & 0x40) == 0) {
                    canBeUTF8 = false;
                } else {
                    utf8BytesLeft++;
                    if ((value & 0x20) == 0) {
                        utf2BytesChars++;
                    } else {
                        utf8BytesLeft++;
                        if ((value & 0x10) == 0) {
                            utf3BytesChars++;
                        } else {
                            utf8BytesLeft++;
                            if ((value & 0x08) == 0) {
                                utf4BytesChars++;
                            } else {
                                canBeUTF8 = false;
                            }
                        }
                    }
                }
            } //else {
            //utf8LowChars++;
            //}
        }

        // ISO-8859-1 stuff
        if (canBeISO88591) {
            if (value > 0x7F && value < 0xA0) {
                canBeISO88591 = false;
            } else if (value > 0x9F) {
                if (value < 0xC0 || value == 0xD7 || value == 0xF7) {
                    isoHighOther++;
                } //else {
                //isoHighChars++;
                //}
            } //else {
            //isoLowChars++;
            //}
        }

        // Shift_JIS stuff
        if (canBeShiftJIS) {
            if (sjisBytesLeft > 0) {
                if (value < 0x40 || value == 0x7F || value > 0xFC) {
                    canBeShiftJIS = false;
                } else {
                    sjisBytesLeft--;
                }
            } else if (value == 0x80 || value == 0xA0 || value > 0xEF) {
                canBeShiftJIS = false;
            } else if (value > 0xA0 && value < 0xE0) {
                sjisKatakanaChars++;
                sjisCurDoubleBytesWordLength = 0;
                sjisCurKatakanaWordLength++;
                if (sjisCurKatakanaWordLength > sjisMaxKatakanaWordLength) {
                    sjisMaxKatakanaWordLength = sjisCurKatakanaWordLength;
                }
            } else if (value > 0x7F) {
                sjisBytesLeft++;
                //sjisDoubleBytesChars++;
                sjisCurKatakanaWordLength = 0;
                sjisCurDoubleBytesWordLength++;
                if (sjisCurDoubleBytesWordLength > sjisMaxDoubleBytesWordLength) {
                    sjisMaxDoubleBytesWordLength = sjisCurDoubleBytesWordLength;
                }
            } else {
                //sjisLowChars++;
                sjisCurKatakanaWordLength = 0;
                sjisCurDoubleBytesWordLength = 0;
            }
        }
    }

    if (canBeUTF8 && utf8BytesLeft > 0) {
        canBeUTF8 = false;
    }
    if (canBeShiftJIS && sjisBytesLeft > 0) {
        canBeShiftJIS = false;
    }

    // Easy -- if there is BOM or at least 1 valid not-single byte character (and no evidence it can't be UTF-8), done
    if (canBeUTF8 && (utf8bom || utf2BytesChars + utf3BytesChars + utf4BytesChars > 0)) {
        return UTF8;
    }
    // Easy -- if assuming Shift_JIS or at least 3 valid consecutive not-ascii characters (and no evidence it can't be), done
    if (canBeShiftJIS && (ASSUME_SHIFT_JIS || sjisMaxKatakanaWordLength >= 3 || sjisMaxDoubleBytesWordLength >= 3)) {
        return SHIFT_JIS;
    }
    // Distinguishing Shift_JIS and ISO-8859-1 can be a little tough for short words. The crude heuristic is:
    // - If we saw
    //   - only two consecutive katakana chars in the whole text, or
    //   - at least 10% of bytes that could be "upper" not-alphanumeric Latin1,
    // - then we conclude Shift_JIS, else ISO-8859-1
    if (canBeISO88591 && canBeShiftJIS) {
        return (sjisMaxKatakanaWordLength == 2 && sjisKatakanaChars == 2) || isoHighOther * 10 >= length
               ? SHIFT_JIS : ISO88591;
    }

    // Otherwise, try in order ISO-8859-1, Shift JIS, UTF-8 and fall back to default platform encoding
    if (canBeISO88591) {
        return ISO88591;
    }
    if (canBeShiftJIS) {
        return SHIFT_JIS;
    }
    if (canBeUTF8) {
        return UTF8;
    }
    // Otherwise, we take a wild guess with platform encoding
    return PLATFORM_DEFAULT_ENCODING;
}