File indexing completed on 2024-12-01 12:33:54

 /*
     This file is part of the KDE libraries
 
     Copyright (C) 1999 Lars Knoll (knoll@kde.org)
     Copyright (C) 2003 Dirk Mueller (mueller@kde.org)
     Copyright (C) 2003 Apple Computer, Inc.
     Copyright (C) 2007 Nick Shaforostoff (shafff@ukr.net)
 
     This library is free software; you can redistribute it and/or
     modify it under the terms of the GNU Library General Public
     License as published by the Free Software Foundation; either
     version 2 of the License, or (at your option) any later version.
 
     This library is distributed in the hope that it will be useful,
     but WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     Library General Public License for more details.
 
     You should have received a copy of the GNU Library General Public License
     along with this library; see the file COPYING.LIB.  If not, write to
     the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
     Boston, MA 02110-1301, USA.
 */
 //----------------------------------------------------------------------------
 //
 // decoder for input stream
 
 #include "kencodingdetector.h"
 
 #undef DECODE_DEBUG
 //#define DECODE_DEBUG
 
 #define MAX_BUFFER 16*1024
 
 #include <assert.h>
 
 #include "guess_ja_p.h"
 
 #include "khtml_debug.h"
 #include <QRegExp>
 #include <QTextCodec>
 
 #include "kcharsets.h"
 #include <klocalizedstring.h>
 
 #include <ctype.h>
 
 enum MIB {
     MibLatin1  = 4,
     Mib8859_8  = 85,
     MibUtf8    = 106,
     MibUcs2    = 1000,
     MibUtf16   = 1015,
     MibUtf16BE = 1013,
     MibUtf16LE = 1014
 };
 
 static bool is16Bit(QTextCodec *codec)
 {
     switch (codec->mibEnum()) {
     case MibUtf16:
     case MibUtf16BE:
     case MibUtf16LE:
     case MibUcs2:
         return true;
     default:
         return false;
     }
 }
 
 class KEncodingDetectorPrivate
 {
 public:
     QTextCodec *m_codec;
     QTextDecoder *m_decoder; // utf16
     QTextCodec *m_defaultCodec;
     QByteArray  m_storeDecoderName;
 
     KEncodingDetector::EncodingChoiceSource m_source;
     KEncodingDetector::AutoDetectScript m_autoDetectLanguage;
 
     bool m_visualRTL : 1;
     bool m_seenBody : 1;
     bool m_writtingHappened : 1;
     bool m_analyzeCalled : 1; //for decode()
     int m_multiByte;
 
     QByteArray m_bufferForDefferedEncDetection;
 
     KEncodingDetectorPrivate()
         : m_codec(QTextCodec::codecForMib(MibLatin1))
         , m_decoder(m_codec->makeDecoder())
         , m_defaultCodec(m_codec)
         , m_source(KEncodingDetector::DefaultEncoding)
         , m_autoDetectLanguage(KEncodingDetector::SemiautomaticDetection)
         , m_visualRTL(false)
         , m_seenBody(false)
         , m_writtingHappened(false)
         , m_analyzeCalled(false)
         , m_multiByte(0)
     {
     }
 
     KEncodingDetectorPrivate(QTextCodec *codec, KEncodingDetector::EncodingChoiceSource source, KEncodingDetector::AutoDetectScript script)
         : m_codec(codec)
         , m_decoder(m_codec->makeDecoder())
         , m_defaultCodec(m_codec)
         , m_source(source)
         , m_autoDetectLanguage(script)
         , m_visualRTL(false)
         , m_seenBody(false)
         , m_writtingHappened(false)
         , m_analyzeCalled(false)
         , m_multiByte(0)
     {
     }
 
     ~KEncodingDetectorPrivate()
     {
         delete m_decoder;
     }
 
     // Returns true if the encoding was explicitly specified someplace.
     bool isExplicitlySpecifiedEncoding()
     {
         return m_source != KEncodingDetector::DefaultEncoding && m_source != KEncodingDetector::AutoDetectedEncoding;
     }
 };
 
 static QByteArray automaticDetectionForArabic(const unsigned char *ptr, int size)
 {
     for (int i = 0; i < size; ++i) {
         if ((ptr[ i ] >= 0x80 && ptr[ i ] <= 0x9F) || ptr[ i ] == 0xA1 || ptr[ i ] == 0xA2 || ptr[ i ] == 0xA3
                 || (ptr[ i ] >= 0xA5 && ptr[ i ] <= 0xAB) || (ptr[ i ] >= 0xAE && ptr[ i ] <= 0xBA)
                 || ptr[ i ] == 0xBC || ptr[ i ] == 0xBD || ptr[ i ] == 0xBE || ptr[ i ] == 0xC0
                 || (ptr[ i ] >= 0xDB && ptr[ i ] <= 0xDF) || (ptr[ i ] >= 0xF3)) {
             return "cp1256";
         }
     }
 
     return "iso-8859-6";
 }
 
 static QByteArray automaticDetectionForBaltic(const unsigned char *ptr, int size)
 {
     for (int i = 0; i < size; ++i) {
         if ((ptr[ i ] >= 0x80 && ptr[ i ] <= 0x9E)) {
             return "cp1257";
         }
 
         if (ptr[ i ] == 0xA1 || ptr[ i ] == 0xA5) {
             return "iso-8859-13";
         }
     }
 
     return "iso-8859-13";
 }
 
 static QByteArray automaticDetectionForCentralEuropean(const unsigned char *ptr, int size)
 {
     QByteArray charset = QByteArray();
     for (int i = 0; i < size; ++i) {
         if (ptr[ i ] >= 0x80 && ptr[ i ] <= 0x9F) {
             if (ptr[ i ] == 0x81 || ptr[ i ] == 0x83 || ptr[ i ] == 0x90 || ptr[ i ] == 0x98) {
                 return "ibm852";
             }
 
             if (i + 1 > size) {
                 return "cp1250";
             } else { // maybe ibm852 ?
                 charset = "cp1250";
                 continue;
             }
         }
         if (ptr[ i ] == 0xA5 || ptr[ i ] == 0xAE || ptr[ i ] == 0xBE || ptr[ i ] == 0xC3 || ptr[ i ] == 0xD0 || ptr[ i ] == 0xE3 || ptr[ i ] == 0xF0) {
             if (i + 1 > size) {
                 return "iso-8859-2";
             } else { // maybe ibm852 ?
                 if (charset.isNull()) {
                     charset = "iso-8859-2";
                 }
                 continue;
             }
         }
     }
 
     if (charset.isNull()) {
         charset = "iso-8859-3";
     }
 
     return charset.data();
 }
 
 static QByteArray automaticDetectionForCyrillic(const unsigned char *ptr, int size)
 {
 #ifdef DECODE_DEBUG
     qCWarning(KHTML_LOG) << "KEncodingDetector: Cyr heuristics";
 #endif
 
 //     if (ptr[0]==0xef && ptr[1]==0xbb && ptr[2]==0xbf)
 //         return "utf8";
     int utf8_mark = 0;
     int koi_score = 0;
     int cp1251_score = 0;
 
     int koi_st = 0;
     int cp1251_st = 0;
 
 //     int koi_na=0;
 //     int cp1251_na=0;
 
     int koi_o_capital = 0;
     int koi_o = 0;
     int cp1251_o_capital = 0;
     int cp1251_o = 0;
 
     int koi_a_capital = 0;
     int koi_a = 0;
     int cp1251_a_capital = 0;
     int cp1251_a = 0;
 
     int koi_s_capital = 0;
     int koi_s = 0;
     int cp1251_s_capital = 0;
     int cp1251_s = 0;
 
     int koi_i_capital = 0;
     int koi_i = 0;
     int cp1251_i_capital = 0;
     int cp1251_i = 0;
 
     int cp1251_small_range = 0;
     int koi_small_range = 0;
     int ibm866_small_range = 0;
 
     int i;
     for (i = 1; (i < size) && (cp1251_small_range + koi_small_range < 1000); ++i) {
         if (ptr[i] > 0xdf) {
             ++cp1251_small_range;
 
             if (ptr[i] == 0xee) { //small o
                 ++cp1251_o;
             } else if (ptr[i] == 0xe0) { //small a
                 ++cp1251_a;
             } else if (ptr[i] == 0xe8) { //small i
                 ++cp1251_i;
             } else if (ptr[i] == 0xf1) { //small s
                 ++cp1251_s;
             } else if (ptr[i] == 0xf2 && ptr[i - 1] == 0xf1) { //small st
                 ++cp1251_st;
             }
 
             else if (ptr[i] == 0xef) {
                 ++koi_o_capital;
             } else if (ptr[i] == 0xe1) {
                 ++koi_a_capital;
             } else if (ptr[i] == 0xe9) {
                 ++koi_i_capital;
             } else if (ptr[i] == 0xf3) {
                 ++koi_s_capital;
             }
 
         } else if (ptr[i] > 0xbf) {
             ++koi_small_range;
 
             if (ptr[i] == 0xd0 || ptr[i] == 0xd1) { //small o
                 ++utf8_mark;
             } else if (ptr[i] == 0xcf) { //small o
                 ++koi_o;
             } else if (ptr[i] == 0xc1) { //small a
                 ++koi_a;
             } else if (ptr[i] == 0xc9) { //small i
                 ++koi_i;
             } else if (ptr[i] == 0xd3) { //small s
                 ++koi_s;
             } else if (ptr[i] == 0xd4 && ptr[i - 1] == 0xd3) { //small st
                 ++koi_st;
             }
 
             else if (ptr[i] == 0xce) {
                 ++cp1251_o_capital;
             } else if (ptr[i] == 0xc0) {
                 ++cp1251_a_capital;
             } else if (ptr[i] == 0xc8) {
                 ++cp1251_i_capital;
             } else if (ptr[i] == 0xd1) {
                 ++cp1251_s_capital;
             }
         } else if (ptr[i] > 0x9f && ptr[i] < 0xb0) { //first 16 letterz is 60%
             ++ibm866_small_range;
         }
 
     }
 
     //cannot decide?
     if (cp1251_small_range + koi_small_range + ibm866_small_range < 8) {
         return "";
     }
 
     if (3 * utf8_mark > cp1251_small_range + koi_small_range + ibm866_small_range) {
 #ifdef DECODE_DEBUG
         qCWarning(KHTML_LOG) << "Cyr Enc Detection: UTF8";
 #endif
         return "UTF-8";
     }
 
     if (ibm866_small_range > cp1251_small_range + koi_small_range) {
         return "ibm866";
     }
 
 //     QByteArray koi_string = "koi8-u";
 //     QByteArray cp1251_string = "cp1251";
 
     if (cp1251_st == 0 && koi_st > 1) {
         koi_score += 10;
     } else if (koi_st == 0 && cp1251_st > 1) {
         cp1251_score += 10;
     }
 
     if (cp1251_st && koi_st) {
         if (cp1251_st / koi_st > 2) {
             cp1251_score += 20;
         } else if (koi_st / cp1251_st > 2) {
             koi_score += 20;
         }
     }
 
     if (cp1251_a > koi_a) {
         cp1251_score += 10;
     } else if (cp1251_a || koi_a) {
         koi_score += 10;
     }
 
     if (cp1251_o > koi_o) {
         cp1251_score += 10;
     } else if (cp1251_o || koi_o) {
         koi_score += 10;
     }
 
     if (cp1251_i > koi_i) {
         cp1251_score += 10;
     } else if (cp1251_i || koi_i) {
         koi_score += 10;
     }
 
     if (cp1251_s > koi_s) {
         cp1251_score += 10;
     } else if (cp1251_s || koi_s) {
         koi_score += 10;
     }
 
     if (cp1251_a_capital > koi_a_capital) {
         cp1251_score += 9;
     } else if (cp1251_a_capital || koi_a_capital) {
         koi_score += 9;
     }
 
     if (cp1251_o_capital > koi_o_capital) {
         cp1251_score += 9;
     } else if (cp1251_o_capital || koi_o_capital) {
         koi_score += 9;
     }
 
     if (cp1251_i_capital > koi_i_capital) {
         cp1251_score += 9;
     } else if (cp1251_i_capital || koi_i_capital) {
         koi_score += 9;
     }
 
     if (cp1251_s_capital > koi_s_capital) {
         cp1251_score += 9;
     } else if (cp1251_s_capital || koi_s_capital) {
         koi_score += 9;
     }
 #ifdef DECODE_DEBUG
     qCWarning(KHTML_LOG) << "koi_score " << koi_score << " cp1251_score " << cp1251_score;
 #endif
     if (abs(koi_score - cp1251_score) < 10) {
         //fallback...
         cp1251_score = cp1251_small_range;
         koi_score = koi_small_range;
     }
     if (cp1251_score > koi_score) {
         return "cp1251";
     } else {
         return "koi8-u";
     }
 
 //     if (cp1251_score>koi_score)
 //         setEncoding("cp1251",AutoDetectedEncoding);
 //     else
 //         setEncoding("koi8-u",AutoDetectedEncoding);
 //     return true;
 
 }
 
 static QByteArray automaticDetectionForGreek(const unsigned char *ptr, int size)
 {
     for (int i = 0; i < size; ++i) {
         if (ptr[ i ] == 0x80 || (ptr[ i ] >= 0x82 && ptr[ i ] <= 0x87) || ptr[ i ] == 0x89 || ptr[ i ] == 0x8B
                 || (ptr[ i ] >= 0x91 && ptr[ i ] <= 0x97) || ptr[ i ] == 0x99 || ptr[ i ] == 0x9B || ptr[ i ] == 0xA4
                 || ptr[ i ] == 0xA5 || ptr[ i ] == 0xAE) {
             return "cp1253";
         }
     }
 
     return "iso-8859-7";
 }
 
 static QByteArray automaticDetectionForHebrew(const unsigned char *ptr, int size)
 {
     for (int i = 0; i < size; ++i) {
         if (ptr[ i ] == 0x80 || (ptr[ i ] >= 0x82 && ptr[ i ] <= 0x89) || ptr[ i ] == 0x8B
                 || (ptr[ i ] >= 0x91 && ptr[ i ] <= 0x99) || ptr[ i ] == 0x9B || ptr[ i ] == 0xA1 || (ptr[ i ] >= 0xBF && ptr[ i ] <= 0xC9)
                 || (ptr[ i ] >= 0xCB && ptr[ i ] <= 0xD8)) {
             return "cp1255";
         }
 
         if (ptr[ i ] == 0xDF) {
             return "iso-8859-8-i";
         }
     }
 
     return "iso-8859-8-i";
 }
 
 static QByteArray automaticDetectionForJapanese(const unsigned char *ptr, int size)
 {
     JapaneseCode kc;
 
     switch (kc.guess_jp((const char *)ptr, size)) {
     case JapaneseCode::JIS:
         return "jis7";
     case JapaneseCode::EUC:
         return "eucjp";
     case JapaneseCode::SJIS:
         return "sjis";
     case JapaneseCode::UTF8:
         return "utf8";
     default:
         break;
     }
 
     return "";
 }
 
 static QByteArray automaticDetectionForTurkish(const unsigned char *ptr, int size)
 {
     for (int i = 0; i < size; ++i) {
         if (ptr[ i ] == 0x80 || (ptr[ i ] >= 0x82 && ptr[ i ] <= 0x8C) || (ptr[ i ] >= 0x91 && ptr[ i ] <= 0x9C) || ptr[ i ] == 0x9F) {
             return "cp1254";
         }
     }
 
     return "iso-8859-9";
 }
 
 static QByteArray automaticDetectionForWesternEuropean(const unsigned char *ptr, int size)
 {
     --size;
     uint nonansi_count = 0;
     for (int i = 0; i < size; ++i) {
         if (ptr[i] > 0x79) {
             ++nonansi_count;
             if (ptr[i] > 0xc1 && ptr[i] < 0xf0 && ptr[i + 1] > 0x7f && ptr[i + 1] < 0xc0) {
                 return "UTF-8";
             }
             if (ptr[i] >= 0x78 && ptr[i] <= 0x9F) {
                 return "cp1252";
             }
         }
 
     }
 
     if (nonansi_count > 0) {
         return "iso-8859-15";
     }
 
     return "";
 }
 
 // Other browsers allow comments in the head section, so we need to also.
 // It's important not to look for tags inside the comments.
 static void skipComment(const char *&ptr, const char *pEnd)
 {
     const char *p = ptr;
     // Allow <!-->; other browsers do.
     if (*p == '>') {
         p++;
     } else {
         while (p != pEnd) {
             if (*p == '-') {
                 // This is the real end of comment, "-->".
                 if (p[1] == '-' && p[2] == '>') {
                     p += 3;
                     break;
                 }
                 // This is the incorrect end of comment that other browsers allow, "--!>".
                 if (p[1] == '-' && p[2] == '!' && p[3] == '>') {
                     p += 4;
                     break;
                 }
             }
             p++;
         }
     }
     ptr = p;
 }
 
 // Returns the position of the encoding string.
 static int findXMLEncoding(const QByteArray &str, int &encodingLength)
 {
     int len = str.length();
     int pos = str.indexOf("encoding");
     if (pos == -1) {
         return -1;
     }
     pos += 8;
 
     // Skip spaces and stray control characters.
     while (pos < len && str[pos] <= ' ') {
         ++pos;
     }
 
     //Bail out if nothing after
     // Skip equals sign.
     if (pos >= len || str[pos] != '=') {
         return -1;
     }
     ++pos;
 
     // Skip spaces and stray control characters.
     while (pos < len && str[pos] <= ' ') {
         ++pos;
     }
 
     //Bail out if nothing after
     if (pos >= len) {
         return -1;
     }
 
     // Skip quotation mark.
     char quoteMark = str[pos];
     if (quoteMark != '"' && quoteMark != '\'') {
         return -1;
     }
     ++pos;
 
     // Find the trailing quotation mark.
     int end = pos;
     while (end < len && str[end] != quoteMark) {
         ++end;
     }
 
     if (end >= len) {
         return -1;
     }
 
     encodingLength = end - pos;
     return pos;
 }
 
 bool KEncodingDetector::processNull(char *data, int len)
 {
     bool bin = false;
     if (is16Bit(d->m_codec)) {
         for (int i = 1; i < len; i += 2) {
             if ((data[i] == '\0') && (data[i - 1] == '\0')) {
                 bin = true;
                 data[i] = ' ';
             }
         }
         return bin;
     }
     // replace '\0' by spaces, for buggy pages
     int i = len - 1;
     while (--i >= 0) {
         if (data[i] == 0) {
             bin = true;
             data[i] = ' ';
         }
     }
     return bin;
 }
 
 bool KEncodingDetector::errorsIfUtf8(const char *data, int length)
 {
     if (d->m_codec->mibEnum() != MibUtf8) {
         return false;    //means no errors
     }
 // #define highest1Bits (unsigned char)0x80
 // #define highest2Bits (unsigned char)0xC0
 // #define highest3Bits (unsigned char)0xE0
 // #define highest4Bits (unsigned char)0xF0
 // #define highest5Bits (unsigned char)0xF8
     static const unsigned char highest1Bits = 0x80;
     static const unsigned char highest2Bits = 0xC0;
     static const unsigned char highest3Bits = 0xE0;
     static const unsigned char highest4Bits = 0xF0;
     static const unsigned char highest5Bits = 0xF8;
 
     for (int i = 0; i < length; ++i) {
         unsigned char c = data[i];
 
         if (d->m_multiByte > 0) {
             if ((c & highest2Bits) == 0x80) {
                 --(d->m_multiByte);
                 continue;
             }
 #ifdef DECODE_DEBUG
             qCWarning(KHTML_LOG) << "EncDetector: Broken UTF8";
 #endif
             return true;
         }
 
         // most significant bit zero, single char
         if ((c & highest1Bits) == 0x00) {
             continue;
         }
 
         // 110xxxxx => init 1 following bytes
         if ((c & highest3Bits) == 0xC0) {
             d->m_multiByte = 1;
             continue;
         }
 
         // 1110xxxx => init 2 following bytes
         if ((c & highest4Bits) == 0xE0) {
             d->m_multiByte = 2;
             continue;
         }
 
         // 11110xxx => init 3 following bytes
         if ((c & highest5Bits) == 0xF0) {
             d->m_multiByte = 3;
             continue;
         }
 #ifdef DECODE_DEBUG
         qCWarning(KHTML_LOG) << "EncDetector:_Broken UTF8";
 #endif
         return true;
     }
     return false;
 }
 
 KEncodingDetector::KEncodingDetector() : d(new KEncodingDetectorPrivate)
 {
 }
 
 KEncodingDetector::KEncodingDetector(QTextCodec *codec, EncodingChoiceSource source, AutoDetectScript script) :
     d(new KEncodingDetectorPrivate(codec, source, script))
 {
 }
 
 KEncodingDetector::~KEncodingDetector()
 {
     delete d;
 }
 
 void KEncodingDetector::setAutoDetectLanguage(KEncodingDetector::AutoDetectScript lang)
 {
     d->m_autoDetectLanguage = lang;
 }
 KEncodingDetector::AutoDetectScript KEncodingDetector::autoDetectLanguage() const
 {
     return d->m_autoDetectLanguage;
 }
 
 KEncodingDetector::EncodingChoiceSource KEncodingDetector::encodingChoiceSource() const
 {
     return d->m_source;
 }
 
 const char *KEncodingDetector::encoding() const
 {
     d->m_storeDecoderName = d->m_codec->name();
     return d->m_storeDecoderName.constData();
 }
 
 bool KEncodingDetector::visuallyOrdered() const
 {
     return d->m_visualRTL;
 }
 
 // const QTextCodec* KEncodingDetector::codec() const
 // {
 //     return d->m_codec;
 // }
 
 QTextDecoder *KEncodingDetector::decoder()
 {
     return d->m_decoder;
 }
 
 void KEncodingDetector::resetDecoder()
 {
     assert(d->m_defaultCodec);
     d->m_bufferForDefferedEncDetection.clear();
     d->m_writtingHappened = false;
     d->m_analyzeCalled = false;
     d->m_multiByte = 0;
     delete d->m_decoder;
     if (!d->m_codec) {
         d->m_codec = d->m_defaultCodec;
     }
     d->m_decoder = d->m_codec->makeDecoder();
 }
 
 bool KEncodingDetector::setEncoding(const char *_encoding, EncodingChoiceSource type)
 {
     QTextCodec *codec;
     QByteArray enc(_encoding);
     if (/*enc.isNull() || */enc.isEmpty()) {
         if (type == DefaultEncoding) {
             codec = d->m_defaultCodec;
         } else {
             return false;
         }
     } else {
         //QString->QTextCodec
 
         enc = enc.toLower();
         // hebrew visually ordered
         if (enc == "visual") {
             enc = "iso8859-8";
         }
         bool b;
         codec = KCharsets::charsets()->codecForName(QLatin1String(enc.data()), b);
         if (!b) {
             return false;
         }
     }
 
     if (d->m_codec->mibEnum() == codec->mibEnum()) {
         // We already have the codec, but we still want to re-set the type,
         // as we may have overwritten a default with a detected
         d->m_source = type;
         return true;
     }
 
     if ((type == EncodingFromMetaTag || type == EncodingFromXMLHeader) && is16Bit(codec)) {
         //Sometimes the codec specified is absurd, i.e. UTF-16 despite
         //us decoding a meta tag as ASCII. In that case, ignore it.
         return false;
     }
 
     if (codec->mibEnum() == Mib8859_8) {
         //We do NOT want to use Qt's QHebrewCodec, since it tries to reorder itself.
         codec = QTextCodec::codecForName("iso8859-8-i");
 
         // visually ordered unless one of the following
         if (!(enc == "iso-8859-8-i" || enc == "iso_8859-8-i" || enc == "csiso88598i" || enc == "logical")) {
             d->m_visualRTL = true;
         }
     }
 
     d->m_codec = codec;
     d->m_source = type;
     delete d->m_decoder;
     d->m_decoder = d->m_codec->makeDecoder();
 #ifdef DECODE_DEBUG
     qCDebug(KHTML_LOG) << "KEncodingDetector::encoding used is" << d->m_codec->name();
 #endif
     return true;
 }
 
 QString KEncodingDetector::decode(const char *data, int len)
 {
     processNull(const_cast<char *>(data), len);
     if (!d->m_analyzeCalled) {
         analyze(data, len);
         d->m_analyzeCalled = true;
     }
 
     return d->m_decoder->toUnicode(data, len);
 }
 
 QString KEncodingDetector::decode(const QByteArray &data)
 {
     processNull(const_cast<char *>(data.data()), data.size());
     if (!d->m_analyzeCalled) {
         analyze(data.data(), data.size());
         d->m_analyzeCalled = true;
     }
 
     return d->m_decoder->toUnicode(data);
 }
 
 QString KEncodingDetector::decodeWithBuffering(const char *data, int len)
 {
 #ifdef DECODE_DEBUG
     qCWarning(KHTML_LOG) << "KEncodingDetector: decoding " << len << " bytes";
 #endif
     if (d->m_writtingHappened) {
 #ifdef DECODE_DEBUG
         qCWarning(KHTML_LOG) << "KEncodingDetector: d->m_writtingHappened " << d->m_codec->name();
 #endif
         processNull(const_cast<char *>(data), len);
         return d->m_decoder->toUnicode(data, len);
     } else {
         if (d->m_bufferForDefferedEncDetection.isEmpty()) {
             // If encoding detection produced something, and we either got to the body or
             // actually saw the encoding explicitly, we're done.
             if (analyze(data, len) && (d->m_seenBody || d->isExplicitlySpecifiedEncoding())) {
 #ifdef DECODE_DEBUG
                 qCWarning(KHTML_LOG) << "KEncodingDetector: m_writtingHappened first time " << d->m_codec->name();
 #endif
                 processNull(const_cast<char *>(data), len);
                 d->m_writtingHappened = true;
                 return d->m_decoder->toUnicode(data, len);
             } else {
 #ifdef DECODE_DEBUG
                 qCWarning(KHTML_LOG) << "KEncodingDetector: begin deffer";
 #endif
                 d->m_bufferForDefferedEncDetection = data;
             }
         } else {
             d->m_bufferForDefferedEncDetection += data;
             // As above, but also limit the buffer size. We must use the entire buffer here,
             // since the boundaries might split the meta tag, etc.
             bool detected = analyze(d->m_bufferForDefferedEncDetection.constData(), d->m_bufferForDefferedEncDetection.length());
             if ((detected && (d->m_seenBody || d->isExplicitlySpecifiedEncoding())) ||
                     d->m_bufferForDefferedEncDetection.length() > MAX_BUFFER) {
                 d->m_writtingHappened = true;
                 d->m_bufferForDefferedEncDetection.replace('\0', ' ');
                 QString result(d->m_decoder->toUnicode(d->m_bufferForDefferedEncDetection));
                 d->m_bufferForDefferedEncDetection.clear();
 #ifdef DECODE_DEBUG
                 qCWarning(KHTML_LOG) << "KEncodingDetector: m_writtingHappened in the middle " << d->m_codec->name();
 #endif
                 return result;
             }
         }
     }
 
     return QString();
 }
 
 bool KEncodingDetector::decodedInvalidCharacters() const
 {
     return d->m_decoder ? d->m_decoder->hasFailure() : false;
 }
 
 QString KEncodingDetector::flush()
 {
     if (d->m_bufferForDefferedEncDetection.isEmpty()) {
         return QString();
     }
 
     d->m_bufferForDefferedEncDetection.replace('\0', ' ');
     QString result(d->m_decoder->toUnicode(d->m_bufferForDefferedEncDetection));
     d->m_bufferForDefferedEncDetection.clear();
 #ifdef DECODE_DEBUG
     qCWarning(KHTML_LOG) << "KEncodingDetector:flush() " << d->m_bufferForDefferedEncDetection.length() << " bytes " << d->m_codec->name();
 #endif
     return result;
 }
 
 bool KEncodingDetector::analyze(const char *data, int len)
 {
     // Check for UTF-16 or UTF-8 BOM mark at the beginning, which is a sure sign of a Unicode encoding.
     // maximumBOMLength = 10
     // Even if the user has chosen utf16 we still need to auto-detect the endianness
     if (len >= 10 && ((d->m_source != UserChosenEncoding) || is16Bit(d->m_codec))) {
         // Extract the first three bytes.
         const uchar *udata = (const uchar *)data;
         uchar c1 = *udata++;
         uchar c2 = *udata++;
         uchar c3 = *udata++;
 
         // Check for the BOM
         const char *autoDetectedEncoding;
         if ((c1 == 0xFE && c2 == 0xFF) || (c1 == 0xFF && c2 == 0xFE)) {
             autoDetectedEncoding = "UTF-16";
         } else if (c1 == 0xEF && c2 == 0xBB && c3 == 0xBF) {
             autoDetectedEncoding = "UTF-8";
         } else if (c1 == 0x00 || c2 == 0x00) {
             uchar c4 = *udata++;
             uchar c5 = *udata++;
             uchar c6 = *udata++;
             uchar c7 = *udata++;
             uchar c8 = *udata++;
             uchar c9 = *udata++;
             uchar c10 = *udata++;
 
             int nul_count_even = (c2 != 0) + (c4 != 0) + (c6 != 0) + (c8 != 0) + (c10 != 0);
             int nul_count_odd = (c1 != 0) + (c3 != 0) + (c5 != 0) + (c7 != 0) + (c9 != 0);
             if ((nul_count_even == 0 && nul_count_odd == 5) || (nul_count_even == 5 && nul_count_odd == 0)) {
                 autoDetectedEncoding = "UTF-16";
             } else {
                 autoDetectedEncoding = nullptr;
             }
         } else {
             autoDetectedEncoding = nullptr;
         }
 
         // If we found a BOM, use the encoding it implies.
         if (autoDetectedEncoding != nullptr) {
             d->m_source = BOM;
             d->m_codec = QTextCodec::codecForName(autoDetectedEncoding);
             assert(d->m_codec);
             //enc = d->m_codec->name();
             delete d->m_decoder;
             d->m_decoder = d->m_codec->makeDecoder();
 #ifdef DECODE_DEBUG
             qCWarning(KHTML_LOG) << "Detection by BOM";
 #endif
             if (is16Bit(d->m_codec) && c2 == 0x00) {
                 // utf16LE, we need to put the decoder in LE mode
                 char reverseUtf16[3] = {(char)0xFF, (char)0xFE, 0x00};
                 d->m_decoder->toUnicode(reverseUtf16, 2);
             }
             return true;
         }
     }
 
     //exit from routine in case it was called to only detect byte order for utf-16
     if (d->m_source == UserChosenEncoding) {
 #ifdef DECODE_DEBUG
         qCWarning(KHTML_LOG) << "KEncodingDetector: UserChosenEncoding exit ";
 #endif
 
         if (errorsIfUtf8(data, len)) {
             setEncoding("", DefaultEncoding);
         }
         return true;
     }
 
     // HTTP header takes precedence over meta-type stuff
     if (d->m_source == EncodingFromHTTPHeader) {
         return true;
     }
 
     if (!d->m_seenBody) {
         // we still don't have an encoding, and are in the head
         // the following tags are allowed in <head>:
         // SCRIPT|STYLE|META|LINK|OBJECT|TITLE|BASE
         const char *ptr = data;
         const char *pEnd = data + len;
 
         while (ptr != pEnd) {
             if (*ptr != '<') {
                 ++ptr;
                 continue;
             }
             ++ptr;
             // Handle comments.
             if (ptr[0] == '!' && ptr[1] == '-' && ptr[2] == '-') {
                 ptr += 3;
                 skipComment(ptr, pEnd);
                 continue;
             }
 
             // Handle XML header, which can have encoding in it.
             if (ptr[0] == '?' && ptr[1] == 'x' && ptr[2] == 'm' && ptr[3] == 'l') {
                 const char *end = ptr;
                 while (*end != '>' && end < pEnd) {
                     end++;
                 }
                 if (*end == '\0' || end == pEnd) {
                     break;
                 }
                 QByteArray str(ptr, end - ptr); // qbytearray provides the \0 terminator
                 int length;
                 int pos = findXMLEncoding(str, length);
                 // also handles the case when specified encoding aint correct
                 if (pos != -1 && setEncoding(str.mid(pos, length).data(), EncodingFromXMLHeader)) {
                     return true;
                 }
             }
 
             //look for <meta>, stop if we reach <body>
             while (
                 !(((*ptr >= 'a') && (*ptr <= 'z')) ||
                   ((*ptr >= 'A') && (*ptr <= 'Z')))
                 && ptr < pEnd
             ) {
                 ++ptr;
             }
 
             char tmp[5];
             int length = 0;
             const char *max = ptr + 4;
             if (pEnd < max) {
                 max = pEnd;
             }
             while (
                 (((*ptr >= 'a') && (*ptr <= 'z')) ||
                  ((*ptr >= 'A') && (*ptr <= 'Z')) ||
                  ((*ptr >= '0') && (*ptr <= '9')))
                 && ptr < max
             ) {
                 tmp[length] = tolower(*ptr);
                 ++ptr;
                 ++length;
             }
             tmp[length] = 0;
             if (tmp[0] == 'm' && tmp[1] == 'e' && tmp[2] == 't' && tmp[3] == 'a') {
                 // found a meta tag...
                 const char *end = ptr;
                 while (*end != '>' && *end != '\0' && end < pEnd) {
                     end++;
                 }
                 //if ( *end == '\0' ) break;
                 const QByteArray str = QByteArray(ptr, (end - ptr) + 1).toLower();
                 const int strLength = str.length();
                 int pos = 0;
                 //if( (pos = str.find("http-equiv", pos)) == -1) break;
                 //if( (pos = str.find("content-type", pos)) == -1) break;
                 if ((pos = str.indexOf("charset")) == -1) {
                     continue;
                 }
                 pos += 6;
                 // skip to '='
                 if ((pos = str.indexOf("=", pos)) == -1) {
                     continue;
                 }
 
                 // skip '='
                 ++pos;
 
                 // skip whitespace before encoding itself
                 while (pos < strLength && str[pos] <= ' ') {
                     ++pos;
                 }
 
                 // there may also be an opening quote, if this is a charset= and not a http-equiv.
                 if (pos < strLength && (str[pos] == '"' || str[pos] == '\'')) {
                     ++pos;
                 }
 
                 // skip whitespace
                 while (pos < strLength && str[pos] <= ' ') {
                     ++pos;
                 }
 
                 if (pos == strLength) {
                     continue;
                 }
 
                 int endpos = pos;
                 while (endpos < strLength &&
                         (str[endpos] != ' ' && str[endpos] != '"' && str[endpos] != '\''
                          && str[endpos] != ';' && str[endpos] != '>')) {
                     ++endpos;
                 }
 #ifdef DECODE_DEBUG
                 qCDebug(KHTML_LOG) << "KEncodingDetector: found charset in <meta>: " << str.mid(pos, endpos - pos).data();
 #endif
                 if (setEncoding(str.mid(pos, endpos - pos).data(), EncodingFromMetaTag)) {
                     return true;
                 }
             } else if (tmp[0] == 'b' && tmp[1] == 'o' && tmp[2] == 'd' && tmp[3] == 'y') {
                 d->m_seenBody = true;
                 break;
             }
         }
     }
 
     if (len < 20) {
         return false;
     }
 
 #ifdef DECODE_DEBUG
     qCDebug(KHTML_LOG) << "KEncodingDetector: using heuristics (" << strlen(data) << ")";
 #endif
 
     switch (d->m_autoDetectLanguage) {
     case KEncodingDetector::Arabic:
         return setEncoding(automaticDetectionForArabic((const unsigned char *) data, len).data(), AutoDetectedEncoding);
 //             break;
     case KEncodingDetector::Baltic:
         return setEncoding(automaticDetectionForBaltic((const unsigned char *) data, len).data(), AutoDetectedEncoding);
 //             break;
     case KEncodingDetector::CentralEuropean:
         return setEncoding(automaticDetectionForCentralEuropean((const unsigned char *) data, len).data(), AutoDetectedEncoding);
 //            break;
     case KEncodingDetector::Cyrillic:
         return setEncoding(automaticDetectionForCyrillic((const unsigned char *) data, len).data(), AutoDetectedEncoding);
 //             break;
     case KEncodingDetector::Greek:
         return setEncoding(automaticDetectionForGreek((const unsigned char *) data, len).data(), AutoDetectedEncoding);
 //             break;
     case KEncodingDetector::Hebrew:
         return setEncoding(automaticDetectionForHebrew((const unsigned char *) data, len).data(), AutoDetectedEncoding);
 //             break;
     case KEncodingDetector::Japanese:
         return setEncoding(automaticDetectionForJapanese((const unsigned char *) data, len).data(), AutoDetectedEncoding);
 //             break;
     case KEncodingDetector::Turkish:
         return setEncoding(automaticDetectionForTurkish((const unsigned char *) data, len).data(), AutoDetectedEncoding);
 //             break;
     case KEncodingDetector::WesternEuropean:
         if (setEncoding(automaticDetectionForWesternEuropean((const unsigned char *) data, len).data(), AutoDetectedEncoding)) {
             return true;
         } else if (d->m_defaultCodec->mibEnum() == MibLatin1) { //detection for khtml
             return setEncoding("iso-8859-15", AutoDetectedEncoding);
         } else { //use default provided by eg katepart
             return setEncoding("", DefaultEncoding);
         }
 //             break;
     case KEncodingDetector::SemiautomaticDetection:
     case KEncodingDetector::ChineseSimplified:
     case KEncodingDetector::ChineseTraditional:
     case KEncodingDetector::Korean:
     case KEncodingDetector::Thai:
     case KEncodingDetector::Unicode:
     case KEncodingDetector::NorthernSaami:
     case KEncodingDetector::SouthEasternEurope:
     case KEncodingDetector::None:
         // huh. somethings broken in this code ### FIXME
         //enc = 0; //Reset invalid codec we tried, so we get back to latin1 fallback.
         break;
     }
 
     return true;
 }
 
 KEncodingDetector::AutoDetectScript KEncodingDetector::scriptForName(const QString &lang)
 {
     if (lang.isEmpty()) {
         return KEncodingDetector::None;
     } else if (lang == i18nc("@item Text character set", "Unicode")) {
         return KEncodingDetector::Unicode;
     } else if (lang == i18nc("@item Text character set", "Cyrillic")) {
         return KEncodingDetector::Cyrillic;
     } else if (lang == i18nc("@item Text character set", "Western European")) {
         return KEncodingDetector::WesternEuropean;
     } else if (lang == i18nc("@item Text character set", "Central European")) {
         return KEncodingDetector::CentralEuropean;
     } else if (lang == i18nc("@item Text character set", "Greek")) {
         return KEncodingDetector::Greek;
     } else if (lang == i18nc("@item Text character set", "Hebrew")) {
         return KEncodingDetector::Hebrew;
     } else if (lang == i18nc("@item Text character set", "Turkish")) {
         return KEncodingDetector::Turkish;
     } else if (lang == i18nc("@item Text character set", "Japanese")) {
         return KEncodingDetector::Japanese;
     } else if (lang == i18nc("@item Text character set", "Baltic")) {
         return KEncodingDetector::Baltic;
     } else if (lang == i18nc("@item Text character set", "Arabic")) {
         return KEncodingDetector::Arabic;
     }
 
     return KEncodingDetector::None;
 }
 
 bool KEncodingDetector::hasAutoDetectionForScript(KEncodingDetector::AutoDetectScript script)
 {
     switch (script) {
     case KEncodingDetector::Arabic:
         return true;
     case KEncodingDetector::Baltic:
         return true;
     case KEncodingDetector::CentralEuropean:
         return true;
     case KEncodingDetector::Cyrillic:
         return true;
     case KEncodingDetector::Greek:
         return true;
     case KEncodingDetector::Hebrew:
         return true;
     case KEncodingDetector::Japanese:
         return true;
     case KEncodingDetector::Turkish:
         return true;
     case KEncodingDetector::WesternEuropean:
         return true;
     case KEncodingDetector::ChineseTraditional:
         return true;
     case KEncodingDetector::ChineseSimplified:
         return true;
     case KEncodingDetector::Unicode:
         return true;
         break;
     default:
         return false;
     }
 }
 
 QString KEncodingDetector::nameForScript(KEncodingDetector::AutoDetectScript script)
 {
     switch (script) {
     case KEncodingDetector::Arabic:
         return i18nc("@item Text character set", "Arabic");
         break;
     case KEncodingDetector::Baltic:
         return i18nc("@item Text character set", "Baltic");
         break;
     case KEncodingDetector::CentralEuropean:
         return i18nc("@item Text character set", "Central European");
         break;
     case KEncodingDetector::Cyrillic:
         return i18nc("@item Text character set", "Cyrillic");
         break;
     case KEncodingDetector::Greek:
         return i18nc("@item Text character set", "Greek");
         break;
     case KEncodingDetector::Hebrew:
         return i18nc("@item Text character set", "Hebrew");
         break;
     case KEncodingDetector::Japanese:
         return i18nc("@item Text character set", "Japanese");
         break;
     case KEncodingDetector::Turkish:
         return i18nc("@item Text character set", "Turkish");
         break;
     case KEncodingDetector::WesternEuropean:
         return i18nc("@item Text character set", "Western European");
         break;
     case KEncodingDetector::ChineseTraditional:
         return i18nc("@item Text character set", "Chinese Traditional");
         break;
     case KEncodingDetector::ChineseSimplified:
         return i18nc("@item Text character set", "Chinese Simplified");
         break;
     case KEncodingDetector::Korean:
         return i18nc("@item Text character set", "Korean");
         break;
     case KEncodingDetector::Thai:
         return i18nc("@item Text character set", "Thai");
         break;
     case KEncodingDetector::Unicode:
         return i18nc("@item Text character set", "Unicode");
         break;
     //case KEncodingDetector::SemiautomaticDetection:
     default:
         return QString();
 
     }
 }
 
 #undef DECODE_DEBUG