icuSources/common/unicode/normalizer2.h

   1 /*
   2 *******************************************************************************
   3 *
   4 *   Copyright (C) 2009-2010, International Business Machines
   5 *   Corporation and others.  All Rights Reserved.
   6 *
   7 *******************************************************************************
   8 *   file name:  normalizer2.h
   9 *   encoding:   US-ASCII
  10 *   tab size:   8 (not used)
  11 *   indentation:4
  12 *
  13 *   created on: 2009nov22
  14 *   created by: Markus W. Scherer
  15 */
  16
  17 #ifndef __NORMALIZER2_H__
  18 #define __NORMALIZER2_H__
  19
  20 /**
  21  * \file
  22  * \brief C++ API: New API for Unicode Normalization.
  23  */
  24
  25 #include "unicode/utypes.h"
  26
  27 #if !UCONFIG_NO_NORMALIZATION
  28
  29 #include "unicode/uniset.h"
  30 #include "unicode/unistr.h"
  31 #include "unicode/unorm2.h"
  32
  33 U_NAMESPACE_BEGIN
  34
  35 /**
  36  * Unicode normalization functionality for standard Unicode normalization or
  37  * for using custom mapping tables.
  38  * All instances of this class are unmodifiable/immutable.
  39  * Instances returned by getInstance() are singletons that must not be deleted by the caller.
  40  * The Normalizer2 class is not intended for public subclassing.
  41  *
  42  * The primary functions are to produce a normalized string and to detect whether
  43  * a string is already normalized.
  44  * The most commonly used normalization forms are those defined in
  45  * http://www.unicode.org/unicode/reports/tr15/
  46  * However, this API supports additional normalization forms for specialized purposes.
  47  * For example, NFKC_Casefold is provided via getInstance("nfkc_cf", COMPOSE)
  48  * and can be used in implementations of UTS #46.
  49  *
  50  * Not only are the standard compose and decompose modes supplied,
  51  * but additional modes are provided as documented in the Mode enum.
  52  *
  53  * Some of the functions in this class identify normalization boundaries.
  54  * At a normalization boundary, the portions of the string
  55  * before it and starting from it do not interact and can be handled independently.
  56  *
  57  * The spanQuickCheckYes() stops at a normalization boundary.
  58  * When the goal is a normalized string, then the text before the boundary
  59  * can be copied, and the remainder can be processed with normalizeSecondAndAppend().
  60  *
  61  * The hasBoundaryBefore(), hasBoundaryAfter() and isInert() functions test whether
  62  * a character is guaranteed to be at a normalization boundary,
  63  * regardless of context.
  64  * This is used for moving from one normalization boundary to the next
  65  * or preceding boundary, and for performing iterative normalization.
  66  *
  67  * Iterative normalization is useful when only a small portion of a
  68  * longer string needs to be processed.
  69  * For example, in ICU, iterative normalization is used by the NormalizationTransliterator
  70  * (to avoid replacing already-normalized text) and ucol_nextSortKeyPart()
  71  * (to process only the substring for which sort key bytes are computed).
  72  *
  73  * The set of normalization boundaries returned by these functions may not be
  74  * complete: There may be more boundaries that could be returned.
  75  * Different functions may return different boundaries.
  76  * @stable ICU 4.4
  77  */
  78 class U_COMMON_API Normalizer2 : public UObject {
  79 public:
  80     /**
  81      * Returns a Normalizer2 instance which uses the specified data file
  82      * (packageName/name similar to ucnv_openPackage() and ures_open()/ResourceBundle)
  83      * and which composes or decomposes text according to the specified mode.
  84      * Returns an unmodifiable singleton instance. Do not delete it.
  85      *
  86      * Use packageName=NULL for data files that are part of ICU's own data.
  87      * Use name="nfc" and UNORM2_COMPOSE/UNORM2_DECOMPOSE for Unicode standard NFC/NFD.
  88      * Use name="nfkc" and UNORM2_COMPOSE/UNORM2_DECOMPOSE for Unicode standard NFKC/NFKD.
  89      * Use name="nfkc_cf" and UNORM2_COMPOSE for Unicode standard NFKC_CF=NFKC_Casefold.
  90      *
  91      * @param packageName NULL for ICU built-in data, otherwise application data package name
  92      * @param name "nfc" or "nfkc" or "nfkc_cf" or name of custom data file
  93      * @param mode normalization mode (compose or decompose etc.)
  94      * @param errorCode Standard ICU error code. Its input value must
  95      *                  pass the U_SUCCESS() test, or else the function returns
  96      *                  immediately. Check for U_FAILURE() on output or use with
  97      *                  function chaining. (See User Guide for details.)
  98      * @return the requested Normalizer2, if successful
  99      * @stable ICU 4.4
 100      */
 101     static const Normalizer2 *
 102     getInstance(const char *packageName,
 103                 const char *name,
 104                 UNormalization2Mode mode,
 105                 UErrorCode &errorCode);
 106
 107     /**
 108      * Returns the normalized form of the source string.
 109      * @param src source string
 110      * @param errorCode Standard ICU error code. Its input value must
 111      *                  pass the U_SUCCESS() test, or else the function returns
 112      *                  immediately. Check for U_FAILURE() on output or use with
 113      *                  function chaining. (See User Guide for details.)
 114      * @return normalized src
 115      * @stable ICU 4.4
 116      */
 117     UnicodeString
 118     normalize(const UnicodeString &src, UErrorCode &errorCode) const {
 119         UnicodeString result;
 120         normalize(src, result, errorCode);
 121         return result;
 122     }
 123     /**
 124      * Writes the normalized form of the source string to the destination string
 125      * (replacing its contents) and returns the destination string.
 126      * The source and destination strings must be different objects.
 127      * @param src source string
 128      * @param dest destination string; its contents is replaced with normalized src
 129      * @param errorCode Standard ICU error code. Its input value must
 130      *                  pass the U_SUCCESS() test, or else the function returns
 131      *                  immediately. Check for U_FAILURE() on output or use with
 132      *                  function chaining. (See User Guide for details.)
 133      * @return dest
 134      * @stable ICU 4.4
 135      */
 136     virtual UnicodeString &
 137     normalize(const UnicodeString &src,
 138               UnicodeString &dest,
 139               UErrorCode &errorCode) const = 0;
 140     /**
 141      * Appends the normalized form of the second string to the first string
 142      * (merging them at the boundary) and returns the first string.
 143      * The result is normalized if the first string was normalized.
 144      * The first and second strings must be different objects.
 145      * @param first string, should be normalized
 146      * @param second string, will be normalized
 147      * @param errorCode Standard ICU error code. Its input value must
 148      *                  pass the U_SUCCESS() test, or else the function returns
 149      *                  immediately. Check for U_FAILURE() on output or use with
 150      *                  function chaining. (See User Guide for details.)
 151      * @return first
 152      * @stable ICU 4.4
 153      */
 154     virtual UnicodeString &
 155     normalizeSecondAndAppend(UnicodeString &first,
 156                              const UnicodeString &second,
 157                              UErrorCode &errorCode) const = 0;
 158     /**
 159      * Appends the second string to the first string
 160      * (merging them at the boundary) and returns the first string.
 161      * The result is normalized if both the strings were normalized.
 162      * The first and second strings must be different objects.
 163      * @param first string, should be normalized
 164      * @param second string, should be normalized
 165      * @param errorCode Standard ICU error code. Its input value must
 166      *                  pass the U_SUCCESS() test, or else the function returns
 167      *                  immediately. Check for U_FAILURE() on output or use with
 168      *                  function chaining. (See User Guide for details.)
 169      * @return first
 170      * @stable ICU 4.4
 171      */
 172     virtual UnicodeString &
 173     append(UnicodeString &first,
 174            const UnicodeString &second,
 175            UErrorCode &errorCode) const = 0;
 176
 177     /**
 178      * Gets the decomposition mapping of c. Equivalent to normalize(UnicodeString(c))
 179      * on a UNORM2_DECOMPOSE Normalizer2 instance, but much faster.
 180      * This function is independent of the mode of the Normalizer2.
 181      * @param c code point
 182      * @param decomposition String object which will be set to c's
 183      *                      decomposition mapping, if there is one.
 184      * @return TRUE if c has a decomposition, otherwise FALSE
 185      * @draft ICU 4.6
 186      */
 187     virtual UBool
 188     getDecomposition(UChar32 c, UnicodeString &decomposition) const = 0;
 189
 190     /**
 191      * Tests if the string is normalized.
 192      * Internally, in cases where the quickCheck() method would return "maybe"
 193      * (which is only possible for the two COMPOSE modes) this method
 194      * resolves to "yes" or "no" to provide a definitive result,
 195      * at the cost of doing more work in those cases.
 196      * @param s input string
 197      * @param errorCode Standard ICU error code. Its input value must
 198      *                  pass the U_SUCCESS() test, or else the function returns
 199      *                  immediately. Check for U_FAILURE() on output or use with
 200      *                  function chaining. (See User Guide for details.)
 201      * @return TRUE if s is normalized
 202      * @stable ICU 4.4
 203      */
 204     virtual UBool
 205     isNormalized(const UnicodeString &s, UErrorCode &errorCode) const = 0;
 206
 207     /**
 208      * Tests if the string is normalized.
 209      * For the two COMPOSE modes, the result could be "maybe" in cases that
 210      * would take a little more work to resolve definitively.
 211      * Use spanQuickCheckYes() and normalizeSecondAndAppend() for a faster
 212      * combination of quick check + normalization, to avoid
 213      * re-checking the "yes" prefix.
 214      * @param s input string
 215      * @param errorCode Standard ICU error code. Its input value must
 216      *                  pass the U_SUCCESS() test, or else the function returns
 217      *                  immediately. Check for U_FAILURE() on output or use with
 218      *                  function chaining. (See User Guide for details.)
 219      * @return UNormalizationCheckResult
 220      * @stable ICU 4.4
 221      */
 222     virtual UNormalizationCheckResult
 223     quickCheck(const UnicodeString &s, UErrorCode &errorCode) const = 0;
 224
 225     /**
 226      * Returns the end of the normalized substring of the input string.
 227      * In other words, with <code>end=spanQuickCheckYes(s, ec);</code>
 228      * the substring <code>UnicodeString(s, 0, end)</code>
 229      * will pass the quick check with a "yes" result.
 230      *
 231      * The returned end index is usually one or more characters before the
 232      * "no" or "maybe" character: The end index is at a normalization boundary.
 233      * (See the class documentation for more about normalization boundaries.)
 234      *
 235      * When the goal is a normalized string and most input strings are expected
 236      * to be normalized already, then call this method,
 237      * and if it returns a prefix shorter than the input string,
 238      * copy that prefix and use normalizeSecondAndAppend() for the remainder.
 239      * @param s input string
 240      * @param errorCode Standard ICU error code. Its input value must
 241      *                  pass the U_SUCCESS() test, or else the function returns
 242      *                  immediately. Check for U_FAILURE() on output or use with
 243      *                  function chaining. (See User Guide for details.)
 244      * @return "yes" span end index
 245      * @stable ICU 4.4
 246      */
 247     virtual int32_t
 248     spanQuickCheckYes(const UnicodeString &s, UErrorCode &errorCode) const = 0;
 249
 250     /**
 251      * Tests if the character always has a normalization boundary before it,
 252      * regardless of context.
 253      * If true, then the character does not normalization-interact with
 254      * preceding characters.
 255      * In other words, a string containing this character can be normalized
 256      * by processing portions before this character and starting from this
 257      * character independently.
 258      * This is used for iterative normalization. See the class documentation for details.
 259      * @param c character to test
 260      * @return TRUE if c has a normalization boundary before it
 261      * @stable ICU 4.4
 262      */
 263     virtual UBool hasBoundaryBefore(UChar32 c) const = 0;
 264
 265     /**
 266      * Tests if the character always has a normalization boundary after it,
 267      * regardless of context.
 268      * If true, then the character does not normalization-interact with
 269      * following characters.
 270      * In other words, a string containing this character can be normalized
 271      * by processing portions up to this character and after this
 272      * character independently.
 273      * This is used for iterative normalization. See the class documentation for details.
 274      * Note that this operation may be significantly slower than hasBoundaryBefore().
 275      * @param c character to test
 276      * @return TRUE if c has a normalization boundary after it
 277      * @stable ICU 4.4
 278      */
 279     virtual UBool hasBoundaryAfter(UChar32 c) const = 0;
 280
 281     /**
 282      * Tests if the character is normalization-inert.
 283      * If true, then the character does not change, nor normalization-interact with
 284      * preceding or following characters.
 285      * In other words, a string containing this character can be normalized
 286      * by processing portions before this character and after this
 287      * character independently.
 288      * This is used for iterative normalization. See the class documentation for details.
 289      * Note that this operation may be significantly slower than hasBoundaryBefore().
 290      * @param c character to test
 291      * @return TRUE if c is normalization-inert
 292      * @stable ICU 4.4
 293      */
 294     virtual UBool isInert(UChar32 c) const = 0;
 295
 296 private:
 297     // No ICU "poor man's RTTI" for this class nor its subclasses.
 298     virtual UClassID getDynamicClassID() const;
 299 };
 300
 301 /**
 302  * Normalization filtered by a UnicodeSet.
 303  * Normalizes portions of the text contained in the filter set and leaves
 304  * portions not contained in the filter set unchanged.
 305  * Filtering is done via UnicodeSet::span(..., USET_SPAN_SIMPLE).
 306  * Not-in-the-filter text is treated as "is normalized" and "quick check yes".
 307  * This class implements all of (and only) the Normalizer2 API.
 308  * An instance of this class is unmodifiable/immutable but is constructed and
 309  * must be destructed by the owner.
 310  * @stable ICU 4.4
 311  */
 312 class U_COMMON_API FilteredNormalizer2 : public Normalizer2 {
 313 public:
 314     /**
 315      * Constructs a filtered normalizer wrapping any Normalizer2 instance
 316      * and a filter set.
 317      * Both are aliased and must not be modified or deleted while this object
 318      * is used.
 319      * The filter set should be frozen; otherwise the performance will suffer greatly.
 320      * @param n2 wrapped Normalizer2 instance
 321      * @param filterSet UnicodeSet which determines the characters to be normalized
 322      * @stable ICU 4.4
 323      */
 324     FilteredNormalizer2(const Normalizer2 &n2, const UnicodeSet &filterSet) :
 325             norm2(n2), set(filterSet) {}
 326
 327     /**
 328      * Writes the normalized form of the source string to the destination string
 329      * (replacing its contents) and returns the destination string.
 330      * The source and destination strings must be different objects.
 331      * @param src source string
 332      * @param dest destination string; its contents is replaced with normalized src
 333      * @param errorCode Standard ICU error code. Its input value must
 334      *                  pass the U_SUCCESS() test, or else the function returns
 335      *                  immediately. Check for U_FAILURE() on output or use with
 336      *                  function chaining. (See User Guide for details.)
 337      * @return dest
 338      * @stable ICU 4.4
 339      */
 340     virtual UnicodeString &
 341     normalize(const UnicodeString &src,
 342               UnicodeString &dest,
 343               UErrorCode &errorCode) const;
 344     /**
 345      * Appends the normalized form of the second string to the first string
 346      * (merging them at the boundary) and returns the first string.
 347      * The result is normalized if the first string was normalized.
 348      * The first and second strings must be different objects.
 349      * @param first string, should be normalized
 350      * @param second string, will be normalized
 351      * @param errorCode Standard ICU error code. Its input value must
 352      *                  pass the U_SUCCESS() test, or else the function returns
 353      *                  immediately. Check for U_FAILURE() on output or use with
 354      *                  function chaining. (See User Guide for details.)
 355      * @return first
 356      * @stable ICU 4.4
 357      */
 358     virtual UnicodeString &
 359     normalizeSecondAndAppend(UnicodeString &first,
 360                              const UnicodeString &second,
 361                              UErrorCode &errorCode) const;
 362     /**
 363      * Appends the second string to the first string
 364      * (merging them at the boundary) and returns the first string.
 365      * The result is normalized if both the strings were normalized.
 366      * The first and second strings must be different objects.
 367      * @param first string, should be normalized
 368      * @param second string, should be normalized
 369      * @param errorCode Standard ICU error code. Its input value must
 370      *                  pass the U_SUCCESS() test, or else the function returns
 371      *                  immediately. Check for U_FAILURE() on output or use with
 372      *                  function chaining. (See User Guide for details.)
 373      * @return first
 374      * @stable ICU 4.4
 375      */
 376     virtual UnicodeString &
 377     append(UnicodeString &first,
 378            const UnicodeString &second,
 379            UErrorCode &errorCode) const;
 380
 381     /**
 382      * Gets the decomposition mapping of c. Equivalent to normalize(UnicodeString(c))
 383      * on a UNORM2_DECOMPOSE Normalizer2 instance, but much faster.
 384      * This function is independent of the mode of the Normalizer2.
 385      * @param c code point
 386      * @param decomposition String object which will be set to c's
 387      *                      decomposition mapping, if there is one.
 388      * @return TRUE if c has a decomposition, otherwise FALSE
 389      * @draft ICU 4.6
 390      */
 391     virtual UBool
 392     getDecomposition(UChar32 c, UnicodeString &decomposition) const;
 393
 394     /**
 395      * Tests if the string is normalized.
 396      * For details see the Normalizer2 base class documentation.
 397      * @param s input string
 398      * @param errorCode Standard ICU error code. Its input value must
 399      *                  pass the U_SUCCESS() test, or else the function returns
 400      *                  immediately. Check for U_FAILURE() on output or use with
 401      *                  function chaining. (See User Guide for details.)
 402      * @return TRUE if s is normalized
 403      * @stable ICU 4.4
 404      */
 405     virtual UBool
 406     isNormalized(const UnicodeString &s, UErrorCode &errorCode) const;
 407     /**
 408      * Tests if the string is normalized.
 409      * For details see the Normalizer2 base class documentation.
 410      * @param s input string
 411      * @param errorCode Standard ICU error code. Its input value must
 412      *                  pass the U_SUCCESS() test, or else the function returns
 413      *                  immediately. Check for U_FAILURE() on output or use with
 414      *                  function chaining. (See User Guide for details.)
 415      * @return UNormalizationCheckResult
 416      * @stable ICU 4.4
 417      */
 418     virtual UNormalizationCheckResult
 419     quickCheck(const UnicodeString &s, UErrorCode &errorCode) const;
 420     /**
 421      * Returns the end of the normalized substring of the input string.
 422      * For details see the Normalizer2 base class documentation.
 423      * @param s input string
 424      * @param errorCode Standard ICU error code. Its input value must
 425      *                  pass the U_SUCCESS() test, or else the function returns
 426      *                  immediately. Check for U_FAILURE() on output or use with
 427      *                  function chaining. (See User Guide for details.)
 428      * @return "yes" span end index
 429      * @stable ICU 4.4
 430      */
 431     virtual int32_t
 432     spanQuickCheckYes(const UnicodeString &s, UErrorCode &errorCode) const;
 433
 434     /**
 435      * Tests if the character always has a normalization boundary before it,
 436      * regardless of context.
 437      * For details see the Normalizer2 base class documentation.
 438      * @param c character to test
 439      * @return TRUE if c has a normalization boundary before it
 440      * @stable ICU 4.4
 441      */
 442     virtual UBool hasBoundaryBefore(UChar32 c) const;
 443
 444     /**
 445      * Tests if the character always has a normalization boundary after it,
 446      * regardless of context.
 447      * For details see the Normalizer2 base class documentation.
 448      * @param c character to test
 449      * @return TRUE if c has a normalization boundary after it
 450      * @stable ICU 4.4
 451      */
 452     virtual UBool hasBoundaryAfter(UChar32 c) const;
 453
 454     /**
 455      * Tests if the character is normalization-inert.
 456      * For details see the Normalizer2 base class documentation.
 457      * @param c character to test
 458      * @return TRUE if c is normalization-inert
 459      * @stable ICU 4.4
 460      */
 461     virtual UBool isInert(UChar32 c) const;
 462 private:
 463     UnicodeString &
 464     normalize(const UnicodeString &src,
 465               UnicodeString &dest,
 466               USetSpanCondition spanCondition,
 467               UErrorCode &errorCode) const;
 468
 469     UnicodeString &
 470     normalizeSecondAndAppend(UnicodeString &first,
 471                              const UnicodeString &second,
 472                              UBool doNormalize,
 473                              UErrorCode &errorCode) const;
 474
 475     const Normalizer2 &norm2;
 476     const UnicodeSet &set;
 477 };
 478
 479 U_NAMESPACE_END
 480
 481 #endif  // !UCONFIG_NO_NORMALIZATION
 482 #endif  // __NORMALIZER2_H__