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| author | Timothy Pearson <kb9vqf@pearsoncomputing.net> | 2011-07-10 15:24:15 -0500 |
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| committer | Timothy Pearson <kb9vqf@pearsoncomputing.net> | 2011-07-10 15:24:15 -0500 |
| commit | bd0f3345a938b35ce6a12f6150373b0955b8dd12 (patch) | |
| tree | 7a520322212d48ebcb9fbe1087e7fca28b76185c /doc/html/qtextcodec.html | |
| download | qt3-bd0f3345a938b35ce6a12f6150373b0955b8dd12.tar.gz qt3-bd0f3345a938b35ce6a12f6150373b0955b8dd12.zip | |
Add Qt3 development HEAD version
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| -rw-r--r-- | doc/html/qtextcodec.html | 611 |
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diff --git a/doc/html/qtextcodec.html b/doc/html/qtextcodec.html new file mode 100644 index 0000000..f8f03c3 --- /dev/null +++ b/doc/html/qtextcodec.html @@ -0,0 +1,611 @@ +<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> +<!-- /home/espenr/tmp/qt-3.3.8-espenr-2499/qt-x11-free-3.3.8/src/codecs/qtextcodec.cpp:201 --> +<html> +<head> +<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> +<title>QTextCodec Class</title> +<style type="text/css"><!-- +fn { margin-left: 1cm; text-indent: -1cm; } +a:link { color: #004faf; text-decoration: none } +a:visited { color: #672967; text-decoration: none } +body { background: #ffffff; color: black; } +--></style> +</head> +<body> + +<table border="0" cellpadding="0" cellspacing="0" width="100%"> +<tr bgcolor="#E5E5E5"> +<td valign=center> + <a href="index.html"> +<font color="#004faf">Home</font></a> + | <a href="classes.html"> +<font color="#004faf">All Classes</font></a> + | <a href="mainclasses.html"> +<font color="#004faf">Main Classes</font></a> + | <a href="annotated.html"> +<font color="#004faf">Annotated</font></a> + | <a href="groups.html"> +<font color="#004faf">Grouped Classes</font></a> + | <a href="functions.html"> +<font color="#004faf">Functions</font></a> +</td> +<td align="right" valign="center"><img src="logo32.png" align="right" width="64" height="32" border="0"></td></tr></table><h1 align=center>QTextCodec Class Reference</h1> + +<p>The QTextCodec class provides conversion between text encodings. +<a href="#details">More...</a> +<p>Almost all the functions in this class are <a href="threads.html#reentrant">reentrant</a> when Qt is built with thread support. The exceptions are <a href="#~QTextCodec"><b>~QTextCodec</b></a>(), <a href="#setCodecForTr"><b>setCodecForTr</b></a>(), <a href="#setCodecForCStrings"><b>setCodecForCStrings</b></a>(), and <a href="#QTextCodec"><b>QTextCodec</b></a>(). +</p><p><tt>#include <<a href="qtextcodec-h.html">qtextcodec.h</a>></tt> +<p>Inherited by <a href="qbig5codec.html">QBig5Codec</a>, <a href="qbig5hkscscodec.html">QBig5hkscsCodec</a>, <a href="qeucjpcodec.html">QEucJpCodec</a>, <a href="qeuckrcodec.html">QEucKrCodec</a>, <a href="qgb18030codec.html">QGb18030Codec</a>, <a href="qjiscodec.html">QJisCodec</a>, <a href="qhebrewcodec.html">QHebrewCodec</a>, <a href="qsjiscodec.html">QSjisCodec</a>, and <a href="qtsciicodec.html">QTsciiCodec</a>. +<p><a href="qtextcodec-members.html">List of all member functions.</a> +<h2>Public Members</h2> +<ul> +<li class=fn>virtual <a href="#~QTextCodec"><b>~QTextCodec</b></a> ()</li> +<li class=fn>virtual const char * <a href="#name"><b>name</b></a> () const = 0</li> +<li class=fn>virtual const char * <a href="#mimeName"><b>mimeName</b></a> () const</li> +<li class=fn>virtual int <a href="#mibEnum"><b>mibEnum</b></a> () const = 0</li> +<li class=fn>virtual QTextDecoder * <a href="#makeDecoder"><b>makeDecoder</b></a> () const</li> +<li class=fn>virtual QTextEncoder * <a href="#makeEncoder"><b>makeEncoder</b></a> () const</li> +<li class=fn>virtual QString <a href="#toUnicode"><b>toUnicode</b></a> ( const char * chars, int len ) const</li> +<li class=fn>virtual QCString <a href="#fromUnicode"><b>fromUnicode</b></a> ( const QString & uc, int & lenInOut ) const</li> +<li class=fn>QCString <a href="#fromUnicode-2"><b>fromUnicode</b></a> ( const QString & uc ) const</li> +<li class=fn>QString <a href="#toUnicode-2"><b>toUnicode</b></a> ( const QByteArray & a, int len ) const</li> +<li class=fn>QString <a href="#toUnicode-3"><b>toUnicode</b></a> ( const QByteArray & a ) const</li> +<li class=fn>QString <a href="#toUnicode-4"><b>toUnicode</b></a> ( const QCString & a, int len ) const</li> +<li class=fn>QString <a href="#toUnicode-5"><b>toUnicode</b></a> ( const QCString & a ) const</li> +<li class=fn>QString <a href="#toUnicode-6"><b>toUnicode</b></a> ( const char * chars ) const</li> +<li class=fn>virtual bool <a href="#canEncode"><b>canEncode</b></a> ( QChar ch ) const</li> +<li class=fn>virtual bool <a href="#canEncode-2"><b>canEncode</b></a> ( const QString & s ) const</li> +<li class=fn>virtual int <a href="#heuristicContentMatch"><b>heuristicContentMatch</b></a> ( const char * chars, int len ) const = 0</li> +<li class=fn>virtual int <a href="#heuristicNameMatch"><b>heuristicNameMatch</b></a> ( const char * hint ) const</li> +</ul> +<h2>Static Public Members</h2> +<ul> +<li class=fn>QTextCodec * <a href="#loadCharmap"><b>loadCharmap</b></a> ( QIODevice * iod )</li> +<li class=fn>QTextCodec * <a href="#loadCharmapFile"><b>loadCharmapFile</b></a> ( QString filename )</li> +<li class=fn>QTextCodec * <a href="#codecForMib"><b>codecForMib</b></a> ( int mib )</li> +<li class=fn>QTextCodec * <a href="#codecForName"><b>codecForName</b></a> ( const char * name, int accuracy = 0 )</li> +<li class=fn>QTextCodec * <a href="#codecForContent"><b>codecForContent</b></a> ( const char * chars, int len )</li> +<li class=fn>QTextCodec * <a href="#codecForIndex"><b>codecForIndex</b></a> ( int i )</li> +<li class=fn>QTextCodec * <a href="#codecForLocale"><b>codecForLocale</b></a> ()</li> +<li class=fn>void <a href="#setCodecForLocale"><b>setCodecForLocale</b></a> ( QTextCodec * c )</li> +<li class=fn>QTextCodec * <a href="#codecForTr"><b>codecForTr</b></a> ()</li> +<li class=fn>void <a href="#setCodecForTr"><b>setCodecForTr</b></a> ( QTextCodec * c )</li> +<li class=fn>QTextCodec * <a href="#codecForCStrings"><b>codecForCStrings</b></a> ()</li> +<li class=fn>void <a href="#setCodecForCStrings"><b>setCodecForCStrings</b></a> ( QTextCodec * c )</li> +<li class=fn>void <a href="#deleteAllCodecs"><b>deleteAllCodecs</b></a> ()</li> +<li class=fn>const char * <a href="#locale"><b>locale</b></a> ()</li> +</ul> +<h2>Protected Members</h2> +<ul> +<li class=fn><a href="#QTextCodec"><b>QTextCodec</b></a> ()</li> +</ul> +<h2>Static Protected Members</h2> +<ul> +<li class=fn>int <a href="#simpleHeuristicNameMatch"><b>simpleHeuristicNameMatch</b></a> ( const char * name, const char * hint )</li> +</ul> +<hr><a name="details"></a><h2>Detailed Description</h2> + + +The QTextCodec class provides conversion between text encodings. + + +<p> Qt uses Unicode to store, draw and manipulate strings. In many +situations you may wish to deal with data that uses a different +encoding. For example, most Japanese documents are still stored in +Shift-JIS or ISO2022, while Russian users often have their +documents in KOI8-R or CP1251. +<p> Qt provides a set of QTextCodec classes to help with converting +non-Unicode formats to and from Unicode. You can also create your +own codec classes (<a href="#subclassing">see later</a>). +<p> The supported encodings are: +<ul> +<li> Latin1 +<li> Big5 -- Chinese +<li> Big5-HKSCS -- Chinese +<li> eucJP -- Japanese +<li> eucKR -- Korean +<li> GB2312 -- Chinese +<li> GBK -- Chinese +<li> GB18030 -- Chinese +<li> JIS7 -- Japanese +<li> Shift-JIS -- Japanese +<li> TSCII -- Tamil +<li> utf8 -- Unicode, 8-bit +<li> utf16 -- Unicode +<li> KOI8-R -- Russian +<li> KOI8-U -- Ukrainian +<li> ISO8859-1 -- Western +<li> ISO8859-2 -- Central European +<li> ISO8859-3 -- Central European +<li> ISO8859-4 -- Baltic +<li> ISO8859-5 -- Cyrillic +<li> ISO8859-6 -- Arabic +<li> ISO8859-7 -- Greek +<li> ISO8859-8 -- Hebrew, visually ordered +<li> ISO8859-8-i -- Hebrew, logically ordered +<li> ISO8859-9 -- Turkish +<li> ISO8859-10 +<li> ISO8859-13 +<li> ISO8859-14 +<li> ISO8859-15 -- Western +<li> IBM 850 +<li> IBM 866 +<li> CP874 +<li> CP1250 -- Central European +<li> CP1251 -- Cyrillic +<li> CP1252 -- Western +<li> CP1253 -- Greek +<li> CP1254 -- Turkish +<li> CP1255 -- Hebrew +<li> CP1256 -- Arabic +<li> CP1257 -- Baltic +<li> CP1258 +<li> Apple Roman +<li> TIS-620 -- Thai +</ul> +<p> QTextCodecs can be used as follows to convert some locally encoded +string to Unicode. Suppose you have some string encoded in Russian +KOI8-R encoding, and want to convert it to Unicode. The simple way +to do this is: +<p> <pre> + <a href="qcstring.html">QCString</a> locallyEncoded = "..."; // text to convert + QTextCodec *codec = QTextCodec::<a href="#codecForName">codecForName</a>("KOI8-R"); // get the codec for KOI8-R + <a href="qstring.html">QString</a> unicodeString = codec-><a href="#toUnicode">toUnicode</a>( locallyEncoded ); + </pre> + +<p> After this, <tt>unicodeString</tt> holds the text converted to Unicode. +Converting a string from Unicode to the local encoding is just as +easy: +<p> <pre> + <a href="qstring.html">QString</a> unicodeString = "..."; // any Unicode text + QTextCodec *codec = QTextCodec::<a href="#codecForName">codecForName</a>("KOI8-R"); // get the codec for KOI8-R + <a href="qcstring.html">QCString</a> locallyEncoded = codec-><a href="#fromUnicode">fromUnicode</a>( unicodeString ); + </pre> + +<p> Some care must be taken when trying to convert the data in chunks, +for example, when receiving it over a network. In such cases it is +possible that a multi-byte character will be split over two +chunks. At best this might result in the loss of a character and +at worst cause the entire conversion to fail. +<p> The approach to use in these situations is to create a <a href="qtextdecoder.html">QTextDecoder</a> +object for the codec and use this QTextDecoder for the whole +decoding process, as shown below: +<p> <pre> + QTextCodec *codec = QTextCodec::<a href="#codecForName">codecForName</a>( "Shift-JIS" ); + <a href="qtextdecoder.html">QTextDecoder</a> *decoder = codec-><a href="#makeDecoder">makeDecoder</a>(); + + <a href="qstring.html">QString</a> unicodeString; + while( receiving_data ) { + <a href="qbytearray.html">QByteArray</a> chunk = new_data; + unicodeString += decoder-><a href="qtextdecoder.html#toUnicode">toUnicode</a>( chunk.<a href="qmemarray.html#data">data</a>(), chunk.length() ); + } + </pre> + +<p> The QTextDecoder object maintains state between chunks and therefore +works correctly even if a multi-byte character is split between +chunks. +<p> <a name="subclassing"></a> +<h3> Creating your own Codec class +</h3> +<a name="1"></a><p> Support for new text encodings can be added to Qt by creating +QTextCodec subclasses. +<p> Built-in codecs can be overridden by custom codecs since more +recently created QTextCodec objects take precedence over earlier +ones. +<p> You may find it more convenient to make your codec class available +as a plugin; see the <a href="plugins-howto.html">plugin + documentation</a> for more details. +<p> The abstract virtual functions describe the encoder to the +system and the coder is used as required in the different +text file formats supported by <a href="qtextstream.html">QTextStream</a>, and under X11, for the +locale-specific character input and output. +<p> To add support for another 8-bit encoding to Qt, make a subclass +of QTextCodec and implement at least the following methods: +<p> <pre> + const char* name() const + </pre> + +Return the official name for the encoding. +<p> <pre> + int mibEnum() const + </pre> + +Return the MIB enum for the encoding if it is listed in the +<a href="http://www.iana.org/assignments/character-sets">IANA character-sets encoding file</a>. +<p> If the encoding is multi-byte then it will have "state"; that is, +the interpretation of some bytes will be dependent on some preceding +bytes. For such encodings, you must implement: +<p> <pre> + <a href="qtextdecoder.html">QTextDecoder</a>* makeDecoder() const + </pre> + +Return a <a href="qtextdecoder.html">QTextDecoder</a> that remembers incomplete multi-byte sequence +prefixes or other required state. +<p> If the encoding does <em>not</em> require state, you should implement: +<p> <pre> + <a href="qstring.html">QString</a> toUnicode(const char* chars, int len) const + </pre> + +Converts <em>len</em> characters from <em>chars</em> to Unicode. +<p> The base QTextCodec class has default implementations of the above +two functions, <em>but they are mutually recursive</em>, so you must +re-implement at least one of them, or both for improved efficiency. +<p> For conversion from Unicode to 8-bit encodings, it is rarely necessary +to maintain state. However, two functions similar to the two above +are used for encoding: +<p> <pre> + <a href="qtextencoder.html">QTextEncoder</a>* makeEncoder() const + </pre> + +Return a <a href="qtextencoder.html">QTextEncoder</a>. +<p> <pre> + <a href="qcstring.html">QCString</a> fromUnicode(const <a href="qstring.html">QString</a>& uc, int& lenInOut ) const + </pre> + +Converts <em>lenInOut</em> characters (of type <a href="qchar.html">QChar</a>) from the start of +the string <em>uc</em>, returning a <a href="qcstring.html">QCString</a> result, and also returning +the <a href="qcstring.html#length">length</a> of the result in +<em>lenInOut</em>. +<p> Again, these are mutually recursive so only one needs to be implemented, +or both if greater efficiency is possible. +<p> Finally, you must implement: +<p> <pre> + int heuristicContentMatch(const char* chars, int len) const + </pre> + +Gives a value indicating how likely it is that <em>len</em> characters +from <em>chars</em> are in the encoding. +<p> A good model for this function is the +QWindowsLocalCodec::heuristicContentMatch function found in the Qt +sources. +<p> A QTextCodec subclass might have improved performance if you also +re-implement: +<p> <pre> + bool canEncode( <a href="qchar.html">QChar</a> ) const + </pre> + +Test if a Unicode character can be encoded. +<p> <pre> + bool canEncode( const <a href="qstring.html">QString</a>& ) const + </pre> + +Test if a string of Unicode characters can be encoded. +<p> <pre> + int heuristicNameMatch(const char* hint) const + </pre> + +Test if a possibly non-standard name is referring to the codec. +<p> Codecs can also be created as <a href="plugins-howto.html">plugins</a>. +<p>See also <a href="i18n.html">Internationalization with Qt</a>. + +<hr><h2>Member Function Documentation</h2> +<h3 class=fn><a name="QTextCodec"></a>QTextCodec::QTextCodec ()<tt> [protected]</tt> +</h3><p><b>Warning:</b> This function is <i>not</i> <a href="threads.html#reentrant">reentrant</a>.</p> + + +<p> Constructs a QTextCodec, and gives it the highest precedence. The +QTextCodec should always be constructed on the heap (i.e. with <tt>new</tt>). Qt takes ownership and will delete it when the application +terminates. + +<h3 class=fn><a name="~QTextCodec"></a>QTextCodec::~QTextCodec ()<tt> [virtual]</tt> +</h3><p><b>Warning:</b> This function is <i>not</i> <a href="threads.html#reentrant">reentrant</a>.</p> + + +<p> Destroys the QTextCodec. Note that you should not delete codecs +yourself: once created they become Qt's responsibility. + +<h3 class=fn>bool <a name="canEncode"></a>QTextCodec::canEncode ( <a href="qchar.html">QChar</a> ch ) const<tt> [virtual]</tt> +</h3> +Returns TRUE if the Unicode character <em>ch</em> can be fully encoded +with this codec; otherwise returns FALSE. The default +implementation tests if the result of <a href="#toUnicode">toUnicode</a>(fromUnicode(ch)) +is the original <em>ch</em>. Subclasses may be able to improve the +efficiency. + +<h3 class=fn>bool <a name="canEncode-2"></a>QTextCodec::canEncode ( const <a href="qstring.html">QString</a> & s ) const<tt> [virtual]</tt> +</h3> +This is an overloaded member function, provided for convenience. It behaves essentially like the above function. +<p> <em>s</em> contains the string being tested for encode-ability. + +<h3 class=fn><a href="qtextcodec.html">QTextCodec</a> * <a name="codecForCStrings"></a>QTextCodec::codecForCStrings ()<tt> [static]</tt> +</h3> + +<p> Returns the codec used by <a href="qstring.html">QString</a> to convert to and from const +char* and QCStrings. If this function returns 0 (the default), +QString assumes Latin-1. +<p> <p>See also <a href="#setCodecForCStrings">setCodecForCStrings</a>(). + +<h3 class=fn><a href="qtextcodec.html">QTextCodec</a> * <a name="codecForContent"></a>QTextCodec::codecForContent ( const char * chars, int len )<tt> [static]</tt> +</h3> +Searches all installed QTextCodec objects, returning the one which +most recognizes the given content. May return 0. +<p> Note that this is often a poor choice, since character encodings +often use most of the available character sequences, and so only +by linguistic analysis could a true match be made. +<p> <em>chars</em> contains the string to check, and <em>len</em> contains the +number of characters in the string to use. +<p> <p>See also <a href="#heuristicContentMatch">heuristicContentMatch</a>(). + +<p>Example: <a href="qwerty-example.html#x391">qwerty/qwerty.cpp</a>. +<h3 class=fn><a href="qtextcodec.html">QTextCodec</a> * <a name="codecForIndex"></a>QTextCodec::codecForIndex ( int i )<tt> [static]</tt> +</h3> +Returns the QTextCodec <em>i</em> positions from the most recently +inserted codec, or 0 if there is no such QTextCodec. Thus, +<a href="#codecForIndex">codecForIndex</a>(0) returns the most recently created QTextCodec. + +<p>Example: <a href="qwerty-example.html#x392">qwerty/qwerty.cpp</a>. +<h3 class=fn><a href="qtextcodec.html">QTextCodec</a> * <a name="codecForLocale"></a>QTextCodec::codecForLocale ()<tt> [static]</tt> +</h3> Returns a pointer to the codec most suitable for this locale. +<p>Example: <a href="qwerty-example.html#x393">qwerty/qwerty.cpp</a>. +<h3 class=fn><a href="qtextcodec.html">QTextCodec</a> * <a name="codecForMib"></a>QTextCodec::codecForMib ( int mib )<tt> [static]</tt> +</h3> +Returns the QTextCodec which matches the <a href="#mibEnum">MIBenum</a> <em>mib</em>. + +<h3 class=fn><a href="qtextcodec.html">QTextCodec</a> * <a name="codecForName"></a>QTextCodec::codecForName ( const char * name, int accuracy = 0 )<tt> [static]</tt> +</h3> +Searches all installed QTextCodec objects and returns the one +which best matches <em>name</em>; the match is case-insensitive. Returns +0 if no codec's <a href="#heuristicNameMatch">heuristicNameMatch</a>() reports a match better than +<em>accuracy</em>, or if <em>name</em> is a null string. +<p> <p>See also <a href="#heuristicNameMatch">heuristicNameMatch</a>(). + +<h3 class=fn><a href="qtextcodec.html">QTextCodec</a> * <a name="codecForTr"></a>QTextCodec::codecForTr ()<tt> [static]</tt> +</h3> + +<p> Returns the codec used by <a href="qobject.html#tr">QObject::tr</a>() on its argument. If this +function returns 0 (the default), tr() assumes Latin-1. +<p> <p>See also <a href="#setCodecForTr">setCodecForTr</a>(). + +<h3 class=fn>void <a name="deleteAllCodecs"></a>QTextCodec::deleteAllCodecs ()<tt> [static]</tt> +</h3> +Deletes all the created codecs. +<p> <b>Warning:</b> Do not call this function. +<p> <a href="qapplication.html">QApplication</a> calls this function just before exiting to delete +any QTextCodec objects that may be lying around. Since various +other classes hold pointers to QTextCodec objects, it is not safe +to call this function earlier. +<p> If you are using the utility classes (like <a href="qstring.html">QString</a>) but not using +QApplication, calling this function at the very end of your +application may be helpful for chasing down memory leaks by +eliminating any QTextCodec objects. + +<h3 class=fn><a href="qcstring.html">QCString</a> <a name="fromUnicode"></a>QTextCodec::fromUnicode ( const <a href="qstring.html">QString</a> & uc, int & lenInOut ) const<tt> [virtual]</tt> +</h3> +QTextCodec subclasses must reimplement either this function or +<a href="#makeEncoder">makeEncoder</a>(). It converts the first <em>lenInOut</em> characters of <em>uc</em> from Unicode to the encoding of the subclass. If <em>lenInOut</em> is +negative or too large, the length of <em>uc</em> is used instead. +<p> Converts <em>lenInOut</em> characters (not bytes) from <em>uc</em>, producing +a <a href="qcstring.html">QCString</a>. <em>lenInOut</em> will be set to the <a href="qcstring.html#length">length</a> of the result (in bytes). +<p> The default implementation makes an encoder with makeEncoder() and +converts the input with that. Note that the default makeEncoder() +implementation makes an encoder that simply calls this function, +hence subclasses <em>must</em> reimplement one function or the other to +avoid infinite recursion. + +<p>Reimplemented in <a href="qhebrewcodec.html#fromUnicode">QHebrewCodec</a>. +<h3 class=fn><a href="qcstring.html">QCString</a> <a name="fromUnicode-2"></a>QTextCodec::fromUnicode ( const <a href="qstring.html">QString</a> & uc ) const +</h3> +This is an overloaded member function, provided for convenience. It behaves essentially like the above function. +<p> <em>uc</em> is the unicode source string. + +<h3 class=fn>int <a name="heuristicContentMatch"></a>QTextCodec::heuristicContentMatch ( const char * chars, int len ) const<tt> [pure virtual]</tt> +</h3> + +<p> QTextCodec subclasses must reimplement this function. It examines +the first <em>len</em> bytes of <em>chars</em> and returns a value indicating +how likely it is that the string is a prefix of text encoded in +the encoding of the subclass. A negative return value indicates +that the text is detectably not in the encoding (e.g. it contains +characters undefined in the encoding). A return value of 0 +indicates that the text should be decoded with this codec rather +than as ASCII, but there is no particular evidence. The value +should range up to <em>len</em>. Thus, most decoders will return -1, 0, +or -<em>len</em>. +<p> The characters are not null terminated. +<p> <p>See also <a href="#codecForContent">codecForContent</a>(). + +<h3 class=fn>int <a name="heuristicNameMatch"></a>QTextCodec::heuristicNameMatch ( const char * hint ) const<tt> [virtual]</tt> +</h3> +Returns a value indicating how likely it is that this decoder is +appropriate for decoding some format that has the given name. The +name is compared with the <em>hint</em>. +<p> A good match returns a positive number around the length of the +string. A bad match is negative. +<p> The default implementation calls <a href="#simpleHeuristicNameMatch">simpleHeuristicNameMatch</a>() with +the name of the codec. + +<h3 class=fn><a href="qtextcodec.html">QTextCodec</a> * <a name="loadCharmap"></a>QTextCodec::loadCharmap ( <a href="qiodevice.html">QIODevice</a> * iod )<tt> [static]</tt> +</h3> +Reads a POSIX2 charmap definition from <em>iod</em>. +The parser recognizes the following lines: +<p> <font name="sans"> + <code_set_name> <i>name</i></br> + <escape_char> <i>character</i></br> + % alias <i>alias</i></br> + CHARMAP</br> + <<i>token</i>> /x<i>hexbyte</i> <U<i>unicode</i>> ...</br> + <<i>token</i>> /d<i>decbyte</i> <U<i>unicode</i>> ...</br> + <<i>token</i>> /<i>octbyte</i> <U<i>unicode</i>> ...</br> + <<i>token</i>> /<i>any</i>/<i>any</i>... <U<i>unicode</i>> ...</br> + END CHARMAP</br> +</font> +<p> The resulting QTextCodec is returned (and also added to the global +list of codecs). The <a href="#name">name</a>() of the result is taken from the +code_set_name. +<p> Note that a codec constructed in this way uses much more memory +and is slower than a hand-written QTextCodec subclass, since +tables in code are kept in memory shared by all Qt applications. +<p> <p>See also <a href="#loadCharmapFile">loadCharmapFile</a>(). + +<p>Example: <a href="qwerty-example.html#x394">qwerty/qwerty.cpp</a>. +<h3 class=fn><a href="qtextcodec.html">QTextCodec</a> * <a name="loadCharmapFile"></a>QTextCodec::loadCharmapFile ( <a href="qstring.html">QString</a> filename )<tt> [static]</tt> +</h3> +A convenience function for <a href="#loadCharmap">loadCharmap</a>() that loads the charmap +definition from the file <em>filename</em>. + +<h3 class=fn>const char * <a name="locale"></a>QTextCodec::locale ()<tt> [static]</tt> +</h3> +Returns a string representing the current language and +sublanguage, e.g. "pt" for Portuguese, or "pt_br" for Portuguese/Brazil. + +<p>Example: <a href="i18n-example.html#x1949">i18n/main.cpp</a>. +<h3 class=fn><a href="qtextdecoder.html">QTextDecoder</a> * <a name="makeDecoder"></a>QTextCodec::makeDecoder () const<tt> [virtual]</tt> +</h3> +Creates a <a href="qtextdecoder.html">QTextDecoder</a> which stores enough state to decode chunks +of char* data to create chunks of Unicode data. The default +implementation creates a stateless decoder, which is only +sufficient for the simplest encodings where each byte corresponds +to exactly one Unicode character. +<p> The caller is responsible for deleting the returned object. + +<h3 class=fn><a href="qtextencoder.html">QTextEncoder</a> * <a name="makeEncoder"></a>QTextCodec::makeEncoder () const<tt> [virtual]</tt> +</h3> +Creates a <a href="qtextencoder.html">QTextEncoder</a> which stores enough state to encode chunks +of Unicode data as char* data. The default implementation creates +a stateless encoder, which is only sufficient for the simplest +encodings where each Unicode character corresponds to exactly one +character. +<p> The caller is responsible for deleting the returned object. + +<h3 class=fn>int <a name="mibEnum"></a>QTextCodec::mibEnum () const<tt> [pure virtual]</tt> +</h3> + +<p> Subclasses of QTextCodec must reimplement this function. It +returns the MIBenum (see <a href="http://www.iana.org/assignments/character-sets">the + IANA character-sets encoding file</a> for more information). +It is important that each QTextCodec subclass returns the correct +unique value for this function. + +<p>Reimplemented in <a href="qeucjpcodec.html#mibEnum">QEucJpCodec</a>. +<h3 class=fn>const char * <a name="mimeName"></a>QTextCodec::mimeName () const<tt> [virtual]</tt> +</h3> +Returns the preferred mime name of the encoding as defined in the +<a href="http://www.iana.org/assignments/character-sets">IANA character-sets encoding file</a>. + +<p>Reimplemented in <a href="qeucjpcodec.html#mimeName">QEucJpCodec</a>, <a href="qeuckrcodec.html#mimeName">QEucKrCodec</a>, <a href="qjiscodec.html#mimeName">QJisCodec</a>, <a href="qhebrewcodec.html#mimeName">QHebrewCodec</a>, and <a href="qsjiscodec.html#mimeName">QSjisCodec</a>. +<h3 class=fn>const char * <a name="name"></a>QTextCodec::name () const<tt> [pure virtual]</tt> +</h3> + +<p> QTextCodec subclasses must reimplement this function. It returns +the name of the encoding supported by the subclass. When choosing +a name for an encoding, consider these points: +<ul> +<li> On X11, <a href="#heuristicNameMatch">heuristicNameMatch</a>( const char * hint ) +is used to test if a the QTextCodec +can convert between Unicode and the encoding of a font +with encoding <em>hint</em>, such as "iso8859-1" for Latin-1 fonts, +"koi8-r" for Russian KOI8 fonts. +The default algorithm of heuristicNameMatch() uses <a href="#name">name</a>(). +<li> Some applications may use this function to present +encodings to the end user. +</ul> + +<p>Example: <a href="qwerty-example.html#x395">qwerty/qwerty.cpp</a>. +<h3 class=fn>void <a name="setCodecForCStrings"></a>QTextCodec::setCodecForCStrings ( <a href="qtextcodec.html">QTextCodec</a> * c )<tt> [static]</tt> +</h3><p><b>Warning:</b> This function is <i>not</i> <a href="threads.html#reentrant">reentrant</a>.</p> + + + +<p> Sets the codec used by <a href="qstring.html">QString</a> to convert to and from const char* +and QCStrings. If <em>c</em> is 0 (the default), QString assumes Latin-1. +<p> <b>Warning:</b> Some codecs do not preserve the characters in the ascii +range (0x00 to 0x7f). For example, the Japanese Shift-JIS +encoding maps the backslash character (0x5a) to the Yen character. +This leads to unexpected results when using the backslash +character to escape characters in strings used in e.g. regular +expressions. Use <a href="qstring.html#fromLatin1">QString::fromLatin1</a>() to preserve characters in +the ascii range when needed. +<p> <p>See also <a href="#codecForCStrings">codecForCStrings</a>() and <a href="#setCodecForTr">setCodecForTr</a>(). + +<h3 class=fn>void <a name="setCodecForLocale"></a>QTextCodec::setCodecForLocale ( <a href="qtextcodec.html">QTextCodec</a> * c )<tt> [static]</tt> +</h3> +Set the codec to <em>c</em>; this will be returned by <a href="#codecForLocale">codecForLocale</a>(). +This might be needed for some applications that want to use their +own mechanism for setting the locale. +<p> <p>See also <a href="#codecForLocale">codecForLocale</a>(). + +<h3 class=fn>void <a name="setCodecForTr"></a>QTextCodec::setCodecForTr ( <a href="qtextcodec.html">QTextCodec</a> * c )<tt> [static]</tt> +</h3><p><b>Warning:</b> This function is <i>not</i> <a href="threads.html#reentrant">reentrant</a>.</p> + + + +<p> Sets the codec used by <a href="qobject.html#tr">QObject::tr</a>() on its argument to <em>c</em>. If +<em>c</em> is 0 (the default), tr() assumes Latin-1. +<p> If the literal quoted text in the program is not in the Latin-1 +encoding, this function can be used to set the appropriate +encoding. For example, software developed by Korean programmers +might use eucKR for all the text in the program, in which case the +main() function might look like this: +<p> <pre> + int main(int argc, char** argv) + { + <a href="qapplication.html">QApplication</a> app(argc, argv); + ... install any additional codecs ... + QTextCodec::<a href="#setCodecForTr">setCodecForTr</a>( QTextCodec::<a href="#codecForName">codecForName</a>("eucKR") ); + ... + } + </pre> + +<p> Note that this is not the way to select the encoding that the <em>user</em> has chosen. For example, to convert an application containing +literal English strings to Korean, all that is needed is for the +English strings to be passed through tr() and for translation +files to be loaded. For details of <a href="i18n.html#internationalization">internationalization</a>, see the +<a href="i18n.html">Qt internationalization documentation</a>. +<p> <p>See also <a href="#codecForTr">codecForTr</a>() and <a href="#setCodecForCStrings">setCodecForCStrings</a>(). + +<h3 class=fn>int <a name="simpleHeuristicNameMatch"></a>QTextCodec::simpleHeuristicNameMatch ( const char * name, const char * hint )<tt> [static protected]</tt> +</h3> +A simple utility function for <a href="#heuristicNameMatch">heuristicNameMatch</a>(): it does some +very minor character-skipping so that almost-exact matches score +high. <em>name</em> is the text we're matching and <em>hint</em> is used for +the comparison. + +<h3 class=fn><a href="qstring.html">QString</a> <a name="toUnicode"></a>QTextCodec::toUnicode ( const char * chars, int len ) const<tt> [virtual]</tt> +</h3> +QTextCodec subclasses must reimplement this function or +<a href="#makeDecoder">makeDecoder</a>(). It converts the first <em>len</em> characters of <em>chars</em> +to Unicode. +<p> The default implementation makes a decoder with makeDecoder() and +converts the input with that. Note that the default makeDecoder() +implementation makes a decoder that simply calls +this function, hence subclasses <em>must</em> reimplement one function or +the other to avoid infinite recursion. + +<h3 class=fn><a href="qstring.html">QString</a> <a name="toUnicode-2"></a>QTextCodec::toUnicode ( const <a href="qbytearray.html">QByteArray</a> & a, int len ) const +</h3> +This is an overloaded member function, provided for convenience. It behaves essentially like the above function. +<p> <em>a</em> contains the source characters; <em>len</em> contains the number of +characters in <em>a</em> to use. + +<h3 class=fn><a href="qstring.html">QString</a> <a name="toUnicode-3"></a>QTextCodec::toUnicode ( const <a href="qbytearray.html">QByteArray</a> & a ) const +</h3> +This is an overloaded member function, provided for convenience. It behaves essentially like the above function. +<p> <em>a</em> contains the source characters. + +<h3 class=fn><a href="qstring.html">QString</a> <a name="toUnicode-4"></a>QTextCodec::toUnicode ( const <a href="qcstring.html">QCString</a> & a, int len ) const +</h3> +This is an overloaded member function, provided for convenience. It behaves essentially like the above function. +<p> <em>a</em> contains the source characters; <em>len</em> contains the number of +characters in <em>a</em> to use. + +<h3 class=fn><a href="qstring.html">QString</a> <a name="toUnicode-5"></a>QTextCodec::toUnicode ( const <a href="qcstring.html">QCString</a> & a ) const +</h3> +This is an overloaded member function, provided for convenience. It behaves essentially like the above function. +<p> <em>a</em> contains the source characters. + +<h3 class=fn><a href="qstring.html">QString</a> <a name="toUnicode-6"></a>QTextCodec::toUnicode ( const char * chars ) const +</h3> +This is an overloaded member function, provided for convenience. It behaves essentially like the above function. +<p> <em>chars</em> contains the source characters. + +<!-- eof --> +<hr><p> +This file is part of the <a href="index.html">Qt toolkit</a>. +Copyright © 1995-2007 +<a href="http://www.trolltech.com/">Trolltech</a>. All Rights Reserved.<p><address><hr><div align=center> +<table width=100% cellspacing=0 border=0><tr> +<td>Copyright © 2007 +<a href="troll.html">Trolltech</a><td align=center><a href="trademarks.html">Trademarks</a> +<td align=right><div align=right>Qt 3.3.8</div> +</table></div></address></body> +</html> |