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; }
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; }