135 lines
5.4 KiB
C++
135 lines
5.4 KiB
C++
/*
|
|
*******************************************************************************
|
|
* *
|
|
* COPYRIGHT: *
|
|
* IBM Open Class Library *
|
|
* (C) Copyright Taligent, Inc., 1996 *
|
|
* (C) Copyright International Business Machines Corporation, 1996-1998 *
|
|
* Licensed Material - Program-Property of IBM - All Rights Reserved. *
|
|
* US Government Users Restricted Rights - Use, duplication, or disclosure *
|
|
* restricted by GSA ADP Schedule Contract with IBM Corp. *
|
|
* *
|
|
*******************************************************************************
|
|
*/
|
|
|
|
#ifndef COMPITR_H
|
|
#define COMPITR_H
|
|
|
|
|
|
#include "utypes.h"
|
|
#include "unistr.h"
|
|
|
|
|
|
/**
|
|
* <tt>ComposedCharIter</tt> is an iterator class that returns all
|
|
* of the precomposed characters defined in the Unicode standard, along
|
|
* with their decomposed forms. This is often useful when building
|
|
* data tables (<i>e.g.</i> collation tables) which need to treat composed
|
|
* and decomposed characters equivalently.
|
|
* <p>
|
|
* For example, imagine that you have built a collation table with ordering
|
|
* rules for the {@link Normalizer#DECOMP canonically decomposed} forms of all
|
|
* characters used in a particular language. When you process input text using
|
|
* this table, the text must first be decomposed so that it matches the form
|
|
* used in the table. This can impose a performance penalty that may be
|
|
* unacceptable in some situations.
|
|
* <p>
|
|
* You can avoid this problem by ensuring that the collation table contains
|
|
* rules for both the decomposed <i>and</i> composed versions of each character.
|
|
* To do so, use a <tt>ComposedCharIter</tt> to iterate through all of the
|
|
* composed characters in Unicode. If the decomposition for that character
|
|
* consists solely of characters that are listed in your ruleset, you can
|
|
* add a new rule for the composed character that makes it equivalent to
|
|
* its decomposition sequence.
|
|
* <p>
|
|
* Note that <tt>ComposedCharIter</tt> iterates over a <em>static</em> table
|
|
* of the composed characters in Unicode. If you want to iterate over the
|
|
* composed characters in a particular string, use {@link Normalizer} instead.
|
|
* <p>
|
|
* When constructing a <tt>ComposedCharIter</tt> there is one
|
|
* optional feature that you can enable or disable:
|
|
* <ul>
|
|
* <li>{@link Normalizer#IGNORE_HANGUL} - Do not iterate over the Hangul
|
|
* characters and their corresponding Jamo decompositions.
|
|
* This option is off by default (<i>i.e.</i> Hangul processing is enabled)
|
|
* since the Unicode standard specifies that Hangul to Jamo
|
|
* is a canonical decomposition.
|
|
* </ul>
|
|
* <p>
|
|
* <tt>ComposedCharIter</tt> is currently based on version 2.1.8 of the
|
|
* <a href="http://www.unicode.org" target="unicode">Unicode Standard</a>.
|
|
* It will be updated as later versions of Unicode are released.
|
|
*/
|
|
class U_COMMON_API ComposedCharIter
|
|
{
|
|
public:
|
|
/**
|
|
* Constant that indicates the iteration has completed.
|
|
* {@link #next} returns this value when there are no more composed
|
|
* characters over which to iterate.
|
|
*/
|
|
static const UChar DONE;
|
|
|
|
/**
|
|
* Construct a new <tt>ComposedCharIter</tt>. The iterator will return
|
|
* all Unicode characters with canonical decompositions, including Korean
|
|
* Hangul characters.
|
|
*/
|
|
ComposedCharIter();
|
|
|
|
|
|
/**
|
|
* Constructs a non-default <tt>ComposedCharIter</tt> with optional behavior.
|
|
* <p>
|
|
* @param compat <tt>false</tt> for canonical decompositions only;
|
|
* <tt>true</tt> for both canonical and compatibility
|
|
* decompositions.
|
|
*
|
|
* @param options Optional decomposition features. Currently, the only
|
|
* supported option is {@link Normalizer#IGNORE_HANGUL}, which
|
|
* causes this <tt>ComposedCharIter</tt> not to iterate
|
|
* over the Hangul characters and their corresponding
|
|
* Jamo decompositions.
|
|
*/
|
|
ComposedCharIter(bool_t compat, int32_t options);
|
|
|
|
/**
|
|
* Determines whether there any precomposed Unicode characters not yet returned
|
|
* by {@link #next}.
|
|
*/
|
|
bool_t hasNext(void) const;
|
|
|
|
/**
|
|
* Returns the next precomposed Unicode character.
|
|
* Repeated calls to <tt>next</tt> return all of the precomposed characters defined
|
|
* by Unicode, in ascending order. After all precomposed characters have
|
|
* been returned, {@link #hasNext} will return <tt>false</tt> and further calls
|
|
* to <tt>next</tt> will return {@link #DONE}.
|
|
*/
|
|
UChar next(void);
|
|
|
|
/**
|
|
* Returns the Unicode decomposition of the current character.
|
|
* This method returns the decomposition of the precomposed character most
|
|
* recently returned by {@link #next}. The resulting decomposition is
|
|
* affected by the settings of the options passed to the constructor.
|
|
* {@link Normalizer#COMPATIBILITY COMPATIBILITY}
|
|
* and {@link Normalizer#NO_HANGUL NO_HANGUL} options passed to the constructor.
|
|
*/
|
|
void getDecomposition(UnicodeString& result) const;
|
|
|
|
private:
|
|
void findNextChar(void);
|
|
|
|
int32_t minDecomp;
|
|
bool_t hangul;
|
|
|
|
UChar curChar;
|
|
UChar nextChar;
|
|
};
|
|
|
|
#endif // _COMPITR
|
|
|
|
|
|
|