kdelibs/kdecore/localization/kencodingdetector.cpp

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2014-11-13 01:04:59 +02:00
/*
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 <QRegExp>
#include <QTextCodec>
#include <kglobal.h>
#include <kcharsets.h>
#include <kdebug.h>
#include <klocale.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
kWarning() << "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
kWarning() << "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
kWarning()<<"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
kWarning() << "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
kWarning() << "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 = KGlobal::charsets()->codecForName(QLatin1String(enc), 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
kDebug(6005) << "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
kWarning() << "KEncodingDetector: decoding "<<len<<" bytes";
#endif
if (d->m_writtingHappened)
{
#ifdef DECODE_DEBUG
kWarning() << "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
kWarning() << "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
kWarning() << "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
kWarning() << "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
kWarning() << "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 = 0;
}
else
{
autoDetectedEncoding = 0;
}
// If we found a BOM, use the encoding it implies.
if (autoDetectedEncoding != 0)
{
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
kWarning() << "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
kWarning() << "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), 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;
QByteArray str( ptr, (end-ptr)+1);
str = str.toLower();
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 < (int)str.length() && str[pos] <= ' ')
++pos;
// there may also be an opening quote, if this is a charset= and not
// a http-equiv.
if (pos < (int)str.length() && str[pos] == '"')
++pos;
if ( pos == (int)str.length())
continue;
int endpos = pos;
while( endpos < str.length() &&
(str[endpos] != ' ' && str[endpos] != '"' && str[endpos] != '\''
&& str[endpos] != ';' && str[endpos] != '>') )
++endpos;
#ifdef DECODE_DEBUG
kDebug( 6005 ) << "KEncodingDetector: found charset in <meta>: " << str.mid(pos,endpos-pos).data();
#endif
if (setEncoding(str.mid(pos,endpos-pos), 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
kDebug( 6005 ) << "KEncodingDetector: using heuristics (" << strlen(data) << ")";
#endif
switch ( d->m_autoDetectLanguage)
{
case KEncodingDetector::Arabic:
return setEncoding(automaticDetectionForArabic( (const unsigned char*) data, len ), AutoDetectedEncoding);
// break;
case KEncodingDetector::Baltic:
return setEncoding(automaticDetectionForBaltic( (const unsigned char*) data, len ), AutoDetectedEncoding);
// break;
case KEncodingDetector::CentralEuropean:
return setEncoding(automaticDetectionForCentralEuropean( (const unsigned char*) data, len ), AutoDetectedEncoding);
break;
case KEncodingDetector::Cyrillic:
return setEncoding(automaticDetectionForCyrillic( (const unsigned char*) data, len), AutoDetectedEncoding);
// break;
case KEncodingDetector::Greek:
return setEncoding(automaticDetectionForGreek( (const unsigned char*) data, len ), AutoDetectedEncoding);
// break;
case KEncodingDetector::Hebrew:
return setEncoding(automaticDetectionForHebrew( (const unsigned char*) data, len ), AutoDetectedEncoding);
// break;
case KEncodingDetector::Japanese:
return setEncoding(automaticDetectionForJapanese( (const unsigned char*) data, len ), AutoDetectedEncoding);
// break;
case KEncodingDetector::Turkish:
return setEncoding(automaticDetectionForTurkish( (const unsigned char*) data, len ), AutoDetectedEncoding);
// break;
case KEncodingDetector::WesternEuropean:
if (setEncoding(automaticDetectionForWesternEuropean( (const unsigned char*) data, len ), 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