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icu46/source/common/unicode/unorm.h

+/*
+*******************************************************************************
+* Copyright (c) 1996-2010, International Business Machines Corporation
+*               and others. All Rights Reserved.
+*******************************************************************************
+* File unorm.h
+*
+* Created by: Vladimir Weinstein 12052000
+*
+* Modification history :
+*
+* Date        Name        Description
+* 02/01/01    synwee      Added normalization quickcheck enum and method.
+*/
+#ifndef UNORM_H
+#define UNORM_H
+
+#include "unicode/utypes.h"
+
+#if !UCONFIG_NO_NORMALIZATION
+
+#include "unicode/uiter.h"
+#include "unicode/unorm2.h"
+
+/**
+ * \file
+ * \brief C API: Unicode Normalization 
+ *
+ * <h2>Unicode normalization API</h2>
+ *
+ * Note: This API has been replaced by the unorm2.h API and is only available
+ * for backward compatibility. The functions here simply delegate to the
+ * unorm2.h functions, for example unorm2_getInstance() and unorm2_normalize().
+ * There is one exception: The new API does not provide a replacement for unorm_compare().
+ *
+ * <code>unorm_normalize</code> transforms Unicode text into an equivalent composed or
+ * decomposed form, allowing for easier sorting and searching of text.
+ * <code>unorm_normalize</code> supports the standard normalization forms described in
+ * <a href="http://www.unicode.org/unicode/reports/tr15/" target="unicode">
+ * Unicode Standard Annex #15: Unicode Normalization Forms</a>.
+ *
+ * Characters with accents or other adornments can be encoded in
+ * several different ways in Unicode.  For example, take the character A-acute.
+ * In Unicode, this can be encoded as a single character (the
+ * "composed" form):
+ *
+ * \code
+ *      00C1    LATIN CAPITAL LETTER A WITH ACUTE
+ * \endcode
+ *
+ * or as two separate characters (the "decomposed" form):
+ *
+ * \code
+ *      0041    LATIN CAPITAL LETTER A
+ *      0301    COMBINING ACUTE ACCENT
+ * \endcode
+ *
+ * To a user of your program, however, both of these sequences should be
+ * treated as the same "user-level" character "A with acute accent".  When you are searching or
+ * comparing text, you must ensure that these two sequences are treated 
+ * equivalently.  In addition, you must handle characters with more than one
+ * accent.  Sometimes the order of a character's combining accents is
+ * significant, while in other cases accent sequences in different orders are
+ * really equivalent.
+ *
+ * Similarly, the string "ffi" can be encoded as three separate letters:
+ *
+ * \code
+ *      0066    LATIN SMALL LETTER F
+ *      0066    LATIN SMALL LETTER F
+ *      0069    LATIN SMALL LETTER I
+ * \endcode
+ *
+ * or as the single character
+ *
+ * \code
+ *      FB03    LATIN SMALL LIGATURE FFI
+ * \endcode
+ *
+ * The ffi ligature is not a distinct semantic character, and strictly speaking
+ * it shouldn't be in Unicode at all, but it was included for compatibility
+ * with existing character sets that already provided it.  The Unicode standard
+ * identifies such characters by giving them "compatibility" decompositions
+ * into the corresponding semantic characters.  When sorting and searching, you
+ * will often want to use these mappings.
+ *
+ * <code>unorm_normalize</code> helps solve these problems by transforming text into the
+ * canonical composed and decomposed forms as shown in the first example above.  
+ * In addition, you can have it perform compatibility decompositions so that 
+ * you can treat compatibility characters the same as their equivalents.
+ * Finally, <code>unorm_normalize</code> rearranges accents into the proper canonical
+ * order, so that you do not have to worry about accent rearrangement on your
+ * own.
+ *
+ * Form FCD, "Fast C or D", is also designed for collation.
+ * It allows to work on strings that are not necessarily normalized
+ * with an algorithm (like in collation) that works under "canonical closure", i.e., it treats precomposed
+ * characters and their decomposed equivalents the same.
+ *
+ * It is not a normalization form because it does not provide for uniqueness of representation. Multiple strings
+ * may be canonically equivalent (their NFDs are identical) and may all conform to FCD without being identical
+ * themselves.
+ *
+ * The form is defined such that the "raw decomposition", the recursive canonical decomposition of each character,
+ * results in a string that is canonically ordered. This means that precomposed characters are allowed for as long
+ * as their decompositions do not need canonical reordering.
+ *
+ * Its advantage for a process like collation is that all NFD and most NFC texts - and many unnormalized texts -
+ * already conform to FCD and do not need to be normalized (NFD) for such a process. The FCD quick check will
+ * return UNORM_YES for most strings in practice.
+ *
+ * unorm_normalize(UNORM_FCD) may be implemented with UNORM_NFD.
+ *
+ * For more details on FCD see the collation design document:
+ * http://source.icu-project.org/repos/icu/icuhtml/trunk/design/collation/ICU_collation_design.htm
+ *
+ * ICU collation performs either NFD or FCD normalization automatically if normalization
+ * is turned on for the collator object.
+ * Beyond collation and string search, normalized strings may be useful for string equivalence comparisons,
+ * transliteration/transcription, unique representations, etc.
+ *
+ * The W3C generally recommends to exchange texts in NFC.
+ * Note also that most legacy character encodings use only precomposed forms and often do not
+ * encode any combining marks by themselves. For conversion to such character encodings the
+ * Unicode text needs to be normalized to NFC.
+ * For more usage examples, see the Unicode Standard Annex.
+ */
+
+/**
+ * Constants for normalization modes.
+ * @stable ICU 2.0
+ */
+typedef enum {
+  /** No decomposition/composition. @stable ICU 2.0 */
+  UNORM_NONE = 1, 
+  /** Canonical decomposition. @stable ICU 2.0 */
+  UNORM_NFD = 2,
+  /** Compatibility decomposition. @stable ICU 2.0 */
+  UNORM_NFKD = 3,
+  /** Canonical decomposition followed by canonical composition. @stable ICU 2.0 */
+  UNORM_NFC = 4,
+  /** Default normalization. @stable ICU 2.0 */
+  UNORM_DEFAULT = UNORM_NFC, 
+  /** Compatibility decomposition followed by canonical composition. @stable ICU 2.0 */
+  UNORM_NFKC =5,
+  /** "Fast C or D" form. @stable ICU 2.0 */
+  UNORM_FCD = 6,
+
+  /** One more than the highest normalization mode constant. @stable ICU 2.0 */
+  UNORM_MODE_COUNT
+} UNormalizationMode;
+
+/**
+ * Constants for options flags for normalization.
+ * Use 0 for default options,
+ * including normalization according to the Unicode version
+ * that is currently supported by ICU (see u_getUnicodeVersion).
+ * @stable ICU 2.6
+ */
+enum {
+    /**
+     * Options bit set value to select Unicode 3.2 normalization
+     * (except NormalizationCorrections).
+     * At most one Unicode version can be selected at a time.
+     * @stable ICU 2.6
+     */
+    UNORM_UNICODE_3_2=0x20
+};
+
+/**
+ * Lowest-order bit number of unorm_compare() options bits corresponding to
+ * normalization options bits.
+ *
+ * The options parameter for unorm_compare() uses most bits for
+ * itself and for various comparison and folding flags.
+ * The most significant bits, however, are shifted down and passed on
+ * to the normalization implementation.
+ * (That is, from unorm_compare(..., options, ...),
+ * options>>UNORM_COMPARE_NORM_OPTIONS_SHIFT will be passed on to the
+ * internal normalization functions.)
+ *
+ * @see unorm_compare
+ * @stable ICU 2.6
+ */
+#define UNORM_COMPARE_NORM_OPTIONS_SHIFT 20
+
+/**
+ * Normalize a string.
+ * The string will be normalized according the specified normalization mode
+ * and options.
+ * The source and result buffers must not be the same, nor overlap.
+ *
+ * @param source The string to normalize.
+ * @param sourceLength The length of source, or -1 if NUL-terminated.
+ * @param mode The normalization mode; one of UNORM_NONE, 
+ *             UNORM_NFD, UNORM_NFC, UNORM_NFKC, UNORM_NFKD, UNORM_DEFAULT.
+ * @param options The normalization options, ORed together (0 for no options).
+ * @param result A pointer to a buffer to receive the result string.
+ *               The result string is NUL-terminated if possible.
+ * @param resultLength The maximum size of result.
+ * @param status A pointer to a UErrorCode to receive any errors.
+ * @return The total buffer size needed; if greater than resultLength,
+ *         the output was truncated, and the error code is set to U_BUFFER_OVERFLOW_ERROR.
+ * @stable ICU 2.0
+ */
+U_STABLE int32_t U_EXPORT2 
+unorm_normalize(const UChar *source, int32_t sourceLength,
+                UNormalizationMode mode, int32_t options,
+                UChar *result, int32_t resultLength,
+                UErrorCode *status);
+
+/**
+ * Performing quick check on a string, to quickly determine if the string is 
+ * in a particular normalization format.
+ * Three types of result can be returned UNORM_YES, UNORM_NO or
+ * UNORM_MAYBE. Result UNORM_YES indicates that the argument
+ * string is in the desired normalized format, UNORM_NO determines that
+ * argument string is not in the desired normalized format. A 
+ * UNORM_MAYBE result indicates that a more thorough check is required, 
+ * the user may have to put the string in its normalized form and compare the 
+ * results.
+ *
+ * @param source       string for determining if it is in a normalized format
+ * @param sourcelength length of source to test, or -1 if NUL-terminated
+ * @param mode         which normalization form to test for
+ * @param status       a pointer to a UErrorCode to receive any errors
+ * @return UNORM_YES, UNORM_NO or UNORM_MAYBE
+ *
+ * @see unorm_isNormalized
+ * @stable ICU 2.0
+ */
+U_STABLE UNormalizationCheckResult U_EXPORT2
+unorm_quickCheck(const UChar *source, int32_t sourcelength,
+                 UNormalizationMode mode,
+                 UErrorCode *status);
+
+/**
+ * Performing quick check on a string; same as unorm_quickCheck but
+ * takes an extra options parameter like most normalization functions.
+ *
+ * @param src        String that is to be tested if it is in a normalization format.
+ * @param srcLength  Length of source to test, or -1 if NUL-terminated.
+ * @param mode       Which normalization form to test for.
+ * @param options    The normalization options, ORed together (0 for no options).
+ * @param pErrorCode ICU error code in/out parameter.
+ *                   Must fulfill U_SUCCESS before the function call.
+ * @return UNORM_YES, UNORM_NO or UNORM_MAYBE
+ *
+ * @see unorm_quickCheck
+ * @see unorm_isNormalized
+ * @stable ICU 2.6
+ */
+U_STABLE UNormalizationCheckResult U_EXPORT2
+unorm_quickCheckWithOptions(const UChar *src, int32_t srcLength, 
+                            UNormalizationMode mode, int32_t options,
+                            UErrorCode *pErrorCode);
+
+/**
+ * Test if a string is in a given normalization form.
+ * This is semantically equivalent to source.equals(normalize(source, mode)) .
+ *
+ * Unlike unorm_quickCheck(), this function returns a definitive result,
+ * never a "maybe".
+ * For NFD, NFKD, and FCD, both functions work exactly the same.
+ * For NFC and NFKC where quickCheck may return "maybe", this function will
+ * perform further tests to arrive at a TRUE/FALSE result.
+ *
+ * @param src        String that is to be tested if it is in a normalization format.
+ * @param srcLength  Length of source to test, or -1 if NUL-terminated.
+ * @param mode       Which normalization form to test for.
+ * @param pErrorCode ICU error code in/out parameter.
+ *                   Must fulfill U_SUCCESS before the function call.
+ * @return Boolean value indicating whether the source string is in the
+ *         "mode" normalization form.
+ *
+ * @see unorm_quickCheck
+ * @stable ICU 2.2
+ */
+U_STABLE UBool U_EXPORT2
+unorm_isNormalized(const UChar *src, int32_t srcLength,
+                   UNormalizationMode mode,
+                   UErrorCode *pErrorCode);
+
+/**
+ * Test if a string is in a given normalization form; same as unorm_isNormalized but
+ * takes an extra options parameter like most normalization functions.
+ *
+ * @param src        String that is to be tested if it is in a normalization format.
+ * @param srcLength  Length of source to test, or -1 if NUL-terminated.
+ * @param mode       Which normalization form to test for.
+ * @param options    The normalization options, ORed together (0 for no options).
+ * @param pErrorCode ICU error code in/out parameter.
+ *                   Must fulfill U_SUCCESS before the function call.
+ * @return Boolean value indicating whether the source string is in the
+ *         "mode/options" normalization form.
+ *
+ * @see unorm_quickCheck
+ * @see unorm_isNormalized
+ * @stable ICU 2.6
+ */
+U_STABLE UBool U_EXPORT2
+unorm_isNormalizedWithOptions(const UChar *src, int32_t srcLength,
+                              UNormalizationMode mode, int32_t options,
+                              UErrorCode *pErrorCode);
+
+/**
+ * Iterative normalization forward.
+ * This function (together with unorm_previous) is somewhat
+ * similar to the C++ Normalizer class (see its non-static functions).
+ *
+ * Iterative normalization is useful when only a small portion of a longer
+ * string/text needs to be processed.
+ *
+ * For example, the likelihood may be high that processing the first 10% of some
+ * text will be sufficient to find certain data.
+ * Another example: When one wants to concatenate two normalized strings and get a
+ * normalized result, it is much more efficient to normalize just a small part of
+ * the result around the concatenation place instead of re-normalizing everything.
+ *
+ * The input text is an instance of the C character iteration API UCharIterator.
+ * It may wrap around a simple string, a CharacterIterator, a Replaceable, or any
+ * other kind of text object.
+ *
+ * If a buffer overflow occurs, then the caller needs to reset the iterator to the
+ * old index and call the function again with a larger buffer - if the caller cares
+ * for the actual output.
+ * Regardless of the output buffer, the iterator will always be moved to the next
+ * normalization boundary.
+ *
+ * This function (like unorm_previous) serves two purposes:
+ *
+ * 1) To find the next boundary so that the normalization of the part of the text
+ * from the current position to that boundary does not affect and is not affected
+ * by the part of the text beyond that boundary.
+ *
+ * 2) To normalize the text up to the boundary.
+ *
+ * The second step is optional, per the doNormalize parameter.
+ * It is omitted for operations like string concatenation, where the two adjacent
+ * string ends need to be normalized together.
+ * In such a case, the output buffer will just contain a copy of the text up to the
+ * boundary.
+ *
+ * pNeededToNormalize is an output-only parameter. Its output value is only defined
+ * if normalization was requested (doNormalize) and successful (especially, no
+ * buffer overflow).
+ * It is useful for operations like a normalizing transliterator, where one would
+ * not want to replace a piece of text if it is not modified.
+ *
+ * If doNormalize==TRUE and pNeededToNormalize!=NULL then *pNeeded... is set TRUE
+ * if the normalization was necessary.
+ *
+ * If doNormalize==FALSE then *pNeededToNormalize will be set to FALSE.
+ *
+ * If the buffer overflows, then *pNeededToNormalize will be undefined;
+ * essentially, whenever U_FAILURE is true (like in buffer overflows), this result
+ * will be undefined.
+ *
+ * @param src The input text in the form of a C character iterator.
+ * @param dest The output buffer; can be NULL if destCapacity==0 for pure preflighting.
+ * @param destCapacity The number of UChars that fit into dest.
+ * @param mode The normalization mode.
+ * @param options The normalization options, ORed together (0 for no options).
+ * @param doNormalize Indicates if the source text up to the next boundary
+ *                    is to be normalized (TRUE) or just copied (FALSE).
+ * @param pNeededToNormalize Output flag indicating if the normalization resulted in
+ *                           different text from the input.
+ *                           Not defined if an error occurs including buffer overflow.
+ *                           Always FALSE if !doNormalize.
+ * @param pErrorCode ICU error code in/out parameter.
+ *                   Must fulfill U_SUCCESS before the function call.
+ * @return Length of output (number of UChars) when successful or buffer overflow.
+ *
+ * @see unorm_previous
+ * @see unorm_normalize
+ *
+ * @stable ICU 2.1
+ */
+U_STABLE int32_t U_EXPORT2
+unorm_next(UCharIterator *src,
+           UChar *dest, int32_t destCapacity,
+           UNormalizationMode mode, int32_t options,
+           UBool doNormalize, UBool *pNeededToNormalize,
+           UErrorCode *pErrorCode);
+
+/**
+ * Iterative normalization backward.
+ * This function (together with unorm_next) is somewhat
+ * similar to the C++ Normalizer class (see its non-static functions).
+ * For all details see unorm_next.
+ *
+ * @param src The input text in the form of a C character iterator.
+ * @param dest The output buffer; can be NULL if destCapacity==0 for pure preflighting.
+ * @param destCapacity The number of UChars that fit into dest.
+ * @param mode The normalization mode.
+ * @param options The normalization options, ORed together (0 for no options).
+ * @param doNormalize Indicates if the source text up to the next boundary
+ *                    is to be normalized (TRUE) or just copied (FALSE).
+ * @param pNeededToNormalize Output flag indicating if the normalization resulted in
+ *                           different text from the input.
+ *                           Not defined if an error occurs including buffer overflow.
+ *                           Always FALSE if !doNormalize.
+ * @param pErrorCode ICU error code in/out parameter.
+ *                   Must fulfill U_SUCCESS before the function call.
+ * @return Length of output (number of UChars) when successful or buffer overflow.
+ *
+ * @see unorm_next
+ * @see unorm_normalize
+ *
+ * @stable ICU 2.1
+ */
+U_STABLE int32_t U_EXPORT2
+unorm_previous(UCharIterator *src,
+               UChar *dest, int32_t destCapacity,
+               UNormalizationMode mode, int32_t options,
+               UBool doNormalize, UBool *pNeededToNormalize,
+               UErrorCode *pErrorCode);
+
+/**
+ * Concatenate normalized strings, making sure that the result is normalized as well.
+ *
+ * If both the left and the right strings are in
+ * the normalization form according to "mode/options",
+ * then the result will be
+ *
+ * \code
+ *     dest=normalize(left+right, mode, options)
+ * \endcode
+ *
+ * With the input strings already being normalized,
+ * this function will use unorm_next() and unorm_previous()
+ * to find the adjacent end pieces of the input strings.
+ * Only the concatenation of these end pieces will be normalized and
+ * then concatenated with the remaining parts of the input strings.
+ *
+ * It is allowed to have dest==left to avoid copying the entire left string.
+ *
+ * @param left Left source string, may be same as dest.
+ * @param leftLength Length of left source string, or -1 if NUL-terminated.
+ * @param right Right source string. Must not be the same as dest, nor overlap.
+ * @param rightLength Length of right source string, or -1 if NUL-terminated.
+ * @param dest The output buffer; can be NULL if destCapacity==0 for pure preflighting.
+ * @param destCapacity The number of UChars that fit into dest.
+ * @param mode The normalization mode.
+ * @param options The normalization options, ORed together (0 for no options).
+ * @param pErrorCode ICU error code in/out parameter.
+ *                   Must fulfill U_SUCCESS before the function call.
+ * @return Length of output (number of UChars) when successful or buffer overflow.
+ *
+ * @see unorm_normalize
+ * @see unorm_next
+ * @see unorm_previous
+ *
+ * @stable ICU 2.1
+ */
+U_STABLE int32_t U_EXPORT2
+unorm_concatenate(const UChar *left, int32_t leftLength,
+                  const UChar *right, int32_t rightLength,
+                  UChar *dest, int32_t destCapacity,
+                  UNormalizationMode mode, int32_t options,
+                  UErrorCode *pErrorCode);
+
+/**
+ * Option bit for unorm_compare:
+ * Both input strings are assumed to fulfill FCD conditions.
+ * @stable ICU 2.2
+ */
+#define UNORM_INPUT_IS_FCD          0x20000
+
+/**
+ * Option bit for unorm_compare:
+ * Perform case-insensitive comparison.
+ * @stable ICU 2.2
+ */
+#define U_COMPARE_IGNORE_CASE       0x10000
+
+#ifndef U_COMPARE_CODE_POINT_ORDER
+/* see also unistr.h and ustring.h */
+/**
+ * Option bit for u_strCaseCompare, u_strcasecmp, unorm_compare, etc:
+ * Compare strings in code point order instead of code unit order.
+ * @stable ICU 2.2
+ */
+#define U_COMPARE_CODE_POINT_ORDER  0x8000
+#endif
+
+/**
+ * Compare two strings for canonical equivalence.
+ * Further options include case-insensitive comparison and
+ * code point order (as opposed to code unit order).
+ *
+ * Canonical equivalence between two strings is defined as their normalized
+ * forms (NFD or NFC) being identical.
+ * This function compares strings incrementally instead of normalizing
+ * (and optionally case-folding) both strings entirely,
+ * improving performance significantly.
+ *
+ * Bulk normalization is only necessary if the strings do not fulfill the FCD
+ * conditions. Only in this case, and only if the strings are relatively long,
+ * is memory allocated temporarily.
+ * For FCD strings and short non-FCD strings there is no memory allocation.
+ *
+ * Semantically, this is equivalent to
+ *   strcmp[CodePointOrder](NFD(foldCase(NFD(s1))), NFD(foldCase(NFD(s2))))
+ * where code point order and foldCase are all optional.
+ *
+ * UAX 21 2.5 Caseless Matching specifies that for a canonical caseless match
+ * the case folding must be performed first, then the normalization.
+ *
+ * @param s1 First source string.
+ * @param length1 Length of first source string, or -1 if NUL-terminated.
+ *
+ * @param s2 Second source string.
+ * @param length2 Length of second source string, or -1 if NUL-terminated.
+ *
+ * @param options A bit set of options:
+ *   - U_FOLD_CASE_DEFAULT or 0 is used for default options:
+ *     Case-sensitive comparison in code unit order, and the input strings
+ *     are quick-checked for FCD.
+ *
+ *   - UNORM_INPUT_IS_FCD
+ *     Set if the caller knows that both s1 and s2 fulfill the FCD conditions.
+ *     If not set, the function will quickCheck for FCD
+ *     and normalize if necessary.
+ *
+ *   - U_COMPARE_CODE_POINT_ORDER
+ *     Set to choose code point order instead of code unit order
+ *     (see u_strCompare for details).
+ *
+ *   - U_COMPARE_IGNORE_CASE
+ *     Set to compare strings case-insensitively using case folding,
+ *     instead of case-sensitively.
+ *     If set, then the following case folding options are used.
+ *
+ *   - Options as used with case-insensitive comparisons, currently:
+ *
+ *   - U_FOLD_CASE_EXCLUDE_SPECIAL_I
+ *    (see u_strCaseCompare for details)
+ *
+ *   - regular normalization options shifted left by UNORM_COMPARE_NORM_OPTIONS_SHIFT
+ *
+ * @param pErrorCode ICU error code in/out parameter.
+ *                   Must fulfill U_SUCCESS before the function call.
+ * @return <0 or 0 or >0 as usual for string comparisons
+ *
+ * @see unorm_normalize
+ * @see UNORM_FCD
+ * @see u_strCompare
+ * @see u_strCaseCompare
+ *
+ * @stable ICU 2.2
+ */
+U_STABLE int32_t U_EXPORT2
+unorm_compare(const UChar *s1, int32_t length1,
+              const UChar *s2, int32_t length2,
+              uint32_t options,
+              UErrorCode *pErrorCode);
+
+#endif /* #if !UCONFIG_NO_NORMALIZATION */
+
+#endif