/*
******************************************************************************
* Copyright (C) 1996-2010, International Business Machines Corporation and
* others. All Rights Reserved.
******************************************************************************
*/

/**
 * \file 
 * \brief C++ API: RuleBasedCollator class provides the simple implementation of Collator.
 */

/**
* File tblcoll.h
*
* Created by: Helena Shih
*
* Modification History:
*
*  Date        Name        Description
*  2/5/97      aliu        Added streamIn and streamOut methods.  Added
*                          constructor which reads RuleBasedCollator object from
*                          a binary file.  Added writeToFile method which streams
*                          RuleBasedCollator out to a binary file.  The streamIn
*                          and streamOut methods use istream and ostream objects
*                          in binary mode.
*  2/12/97     aliu        Modified to use TableCollationData sub-object to
*                          hold invariant data.
*  2/13/97     aliu        Moved several methods into this class from Collation.
*                          Added a private RuleBasedCollator(Locale&) constructor,
*                          to be used by Collator::createDefault().  General
*                          clean up.
*  2/20/97     helena      Added clone, operator==, operator!=, operator=, and copy
*                          constructor and getDynamicClassID.
*  3/5/97      aliu        Modified constructFromFile() to add parameter
*                          specifying whether or not binary loading is to be
*                          attempted.  This is required for dynamic rule loading.
* 05/07/97     helena      Added memory allocation error detection.
*  6/17/97     helena      Added IDENTICAL strength for compare, changed getRules to
*                          use MergeCollation::getPattern.
*  6/20/97     helena      Java class name change.
*  8/18/97     helena      Added internal API documentation.
* 09/03/97     helena      Added createCollationKeyValues().
* 02/10/98     damiba      Added compare with "length" parameter
* 08/05/98     erm         Synched with 1.2 version of RuleBasedCollator.java
* 04/23/99     stephen     Removed EDecompositionMode, merged with
*                          Normalizer::EMode
* 06/14/99     stephen     Removed kResourceBundleSuffix
* 11/02/99     helena      Collator performance enhancements.  Eliminates the
*                          UnicodeString construction and special case for NO_OP.
* 11/23/99     srl         More performance enhancements. Updates to NormalizerIterator
*                          internal state management.
* 12/15/99     aliu        Update to support Thai collation.  Move NormalizerIterator
*                          to implementation file.
* 01/29/01     synwee      Modified into a C++ wrapper which calls C API
*                          (ucol.h)
*/

#ifndef TBLCOLL_H
#define TBLCOLL_H

#include "unicode/utypes.h"

 
#if !UCONFIG_NO_COLLATION

#include "unicode/coll.h"
#include "unicode/ucol.h"
#include "unicode/sortkey.h"
#include "unicode/normlzr.h"

U_NAMESPACE_BEGIN

/**
* @stable ICU 2.0
*/
class StringSearch;
/**
* @stable ICU 2.0
*/
class CollationElementIterator;

/**
 * The RuleBasedCollator class provides the simple implementation of
 * Collator, using data-driven tables. The user can create a customized
 * table-based collation.
 * <P>
 * <em>Important: </em>The ICU collation service has been reimplemented 
 * in order to achieve better performance and UCA compliance. 
 * For details, see the 
 * <a href="http://source.icu-project.org/repos/icu/icuhtml/trunk/design/collation/ICU_collation_design.htm">
 * collation design document</a>.
 * <p>
 * RuleBasedCollator is a thin C++ wrapper over the C implementation.
 * <p>
 * For more information about the collation service see 
 * <a href="http://icu-project.org/userguide/Collate_Intro.html">the users guide</a>.
 * <p>
 * Collation service provides correct sorting orders for most locales supported in ICU. 
 * If specific data for a locale is not available, the orders eventually falls back
 * to the <a href="http://www.unicode.org/unicode/reports/tr10/">UCA sort order</a>. 
 * <p>
 * Sort ordering may be customized by providing your own set of rules. For more on
 * this subject see the <a href="http://icu-project.org/userguide/Collate_Customization.html">
 * Collation customization</a> section of the users guide.
 * <p>
 * Note, RuleBasedCollator is not to be subclassed.
 * @see        Collator
 * @version    2.0 11/15/2001
 */
class U_I18N_API RuleBasedCollator : public Collator
{
public:

  // constructor -------------------------------------------------------------

    /**
     * RuleBasedCollator constructor. This takes the table rules and builds a
     * collation table out of them. Please see RuleBasedCollator class
     * description for more details on the collation rule syntax.
     * @param rules the collation rules to build the collation table from.
     * @param status reporting a success or an error.
     * @see Locale
     * @stable ICU 2.0
     */
    RuleBasedCollator(const UnicodeString& rules, UErrorCode& status);

    /**
     * RuleBasedCollator constructor. This takes the table rules and builds a
     * collation table out of them. Please see RuleBasedCollator class
     * description for more details on the collation rule syntax.
     * @param rules the collation rules to build the collation table from.
     * @param collationStrength default strength for comparison
     * @param status reporting a success or an error.
     * @see Locale
     * @stable ICU 2.0
     */
    RuleBasedCollator(const UnicodeString& rules,
                       ECollationStrength collationStrength,
                       UErrorCode& status);

    /**
     * RuleBasedCollator constructor. This takes the table rules and builds a
     * collation table out of them. Please see RuleBasedCollator class
     * description for more details on the collation rule syntax.
     * @param rules the collation rules to build the collation table from.
     * @param decompositionMode the normalisation mode
     * @param status reporting a success or an error.
     * @see Locale
     * @stable ICU 2.0
     */
    RuleBasedCollator(const UnicodeString& rules,
                    UColAttributeValue decompositionMode,
                    UErrorCode& status);

    /**
     * RuleBasedCollator constructor. This takes the table rules and builds a
     * collation table out of them. Please see RuleBasedCollator class
     * description for more details on the collation rule syntax.
     * @param rules the collation rules to build the collation table from.
     * @param collationStrength default strength for comparison
     * @param decompositionMode the normalisation mode
     * @param status reporting a success or an error.
     * @see Locale
     * @stable ICU 2.0
     */
    RuleBasedCollator(const UnicodeString& rules,
                    ECollationStrength collationStrength,
                    UColAttributeValue decompositionMode,
                    UErrorCode& status);

    /**
     * Copy constructor.
     * @param other the RuleBasedCollator object to be copied
     * @see Locale
     * @stable ICU 2.0
     */
    RuleBasedCollator(const RuleBasedCollator& other);


    /** Opens a collator from a collator binary image created using
    *  cloneBinary. Binary image used in instantiation of the 
    *  collator remains owned by the user and should stay around for 
    *  the lifetime of the collator. The API also takes a base collator
    *  which usualy should be UCA.
    *  @param bin binary image owned by the user and required through the
    *             lifetime of the collator
    *  @param length size of the image. If negative, the API will try to
    *                figure out the length of the image
    *  @param base fallback collator, usually UCA. Base is required to be
    *              present through the lifetime of the collator. Currently 
    *              it cannot be NULL.
    *  @param status for catching errors
    *  @return newly created collator
    *  @see cloneBinary
    *  @stable ICU 3.4
    */
    RuleBasedCollator(const uint8_t *bin, int32_t length, 
                    const RuleBasedCollator *base, 
                    UErrorCode &status);
    // destructor --------------------------------------------------------------

    /**
     * Destructor.
     * @stable ICU 2.0
     */
    virtual ~RuleBasedCollator();

    // public methods ----------------------------------------------------------

    /**
     * Assignment operator.
     * @param other other RuleBasedCollator object to compare with.
     * @stable ICU 2.0
     */
    RuleBasedCollator& operator=(const RuleBasedCollator& other);

    /**
     * Returns true if argument is the same as this object.
     * @param other Collator object to be compared.
     * @return true if arguments is the same as this object.
     * @stable ICU 2.0
     */
    virtual UBool operator==(const Collator& other) const;

    /**
     * Returns true if argument is not the same as this object.
     * @param other Collator object to be compared
     * @return returns true if argument is not the same as this object.
     * @stable ICU 2.0
     */
    virtual UBool operator!=(const Collator& other) const;

    /**
     * Makes a deep copy of the object.
     * The caller owns the returned object.
     * @return the cloned object.
     * @stable ICU 2.0
     */
    virtual Collator* clone(void) const;

    /**
     * Creates a collation element iterator for the source string. The caller of
     * this method is responsible for the memory management of the return
     * pointer.
     * @param source the string over which the CollationElementIterator will
     *        iterate.
     * @return the collation element iterator of the source string using this as
     *         the based Collator.
     * @stable ICU 2.2
     */
    virtual CollationElementIterator* createCollationElementIterator(
                                           const UnicodeString& source) const;

    /**
     * Creates a collation element iterator for the source. The caller of this
     * method is responsible for the memory management of the returned pointer.
     * @param source the CharacterIterator which produces the characters over
     *        which the CollationElementItgerator will iterate.
     * @return the collation element iterator of the source using this as the
     *         based Collator.
     * @stable ICU 2.2
     */
    virtual CollationElementIterator* createCollationElementIterator(
                                         const CharacterIterator& source) const;

    /**
     * Compares a range of character data stored in two different strings based
     * on the collation rules. Returns information about whether a string is
     * less than, greater than or equal to another string in a language.
     * This can be overriden in a subclass.
     * @param source the source string.
     * @param target the target string to be compared with the source string.
     * @return the comparison result. GREATER if the source string is greater
     *         than the target string, LESS if the source is less than the
     *         target. Otherwise, returns EQUAL.
     * @deprecated ICU 2.6 Use overload with UErrorCode&
     */
    virtual EComparisonResult compare(const UnicodeString& source,
                                      const UnicodeString& target) const;


    /**
    * The comparison function compares the character data stored in two
    * different strings. Returns information about whether a string is less 
    * than, greater than or equal to another string.
    * @param source the source string to be compared with.
    * @param target the string that is to be compared with the source string.
    * @param status possible error code
    * @return Returns an enum value. UCOL_GREATER if source is greater
    * than target; UCOL_EQUAL if source is equal to target; UCOL_LESS if source is less
    * than target
    * @stable ICU 2.6
    **/
    virtual UCollationResult compare(const UnicodeString& source,
                                      const UnicodeString& target,
                                      UErrorCode &status) const;

    /**
     * Compares a range of character data stored in two different strings based
     * on the collation rules up to the specified length. Returns information
     * about whether a string is less than, greater than or equal to another
     * string in a language. This can be overriden in a subclass.
     * @param source the source string.
     * @param target the target string to be compared with the source string.
     * @param length compares up to the specified length
     * @return the comparison result. GREATER if the source string is greater
     *         than the target string, LESS if the source is less than the
     *         target. Otherwise, returns EQUAL.
     * @deprecated ICU 2.6 Use overload with UErrorCode&
     */
    virtual EComparisonResult compare(const UnicodeString& source,
                                      const UnicodeString&  target,
                                      int32_t length) const;

    /**
    * Does the same thing as compare but limits the comparison to a specified 
    * length
    * @param source the source string to be compared with.
    * @param target the string that is to be compared with the source string.
    * @param length the length the comparison is limited to
    * @param status possible error code
    * @return Returns an enum value. UCOL_GREATER if source (up to the specified 
    *         length) is greater than target; UCOL_EQUAL if source (up to specified 
    *         length) is equal to target; UCOL_LESS if source (up to the specified 
    *         length) is less  than target.
    * @stable ICU 2.6
    */
    virtual UCollationResult compare(const UnicodeString& source,
                                      const UnicodeString& target,
                                      int32_t length,
                                      UErrorCode &status) const;

    /**
     * The comparison function compares the character data stored in two
     * different string arrays. Returns information about whether a string array
     * is less than, greater than or equal to another string array.
     * <p>Example of use:
     * <pre>
     * .       UChar ABC[] = {0x41, 0x42, 0x43, 0};  // = "ABC"
     * .       UChar abc[] = {0x61, 0x62, 0x63, 0};  // = "abc"
     * .       UErrorCode status = U_ZERO_ERROR;
     * .       Collator *myCollation =
     * .                         Collator::createInstance(Locale::US, status);
     * .       if (U_FAILURE(status)) return;
     * .       myCollation->setStrength(Collator::PRIMARY);
     * .       // result would be Collator::EQUAL ("abc" == "ABC")
     * .       // (no primary difference between "abc" and "ABC")
     * .       Collator::EComparisonResult result =
     * .                             myCollation->compare(abc, 3, ABC, 3);
     * .       myCollation->setStrength(Collator::TERTIARY);
     * .       // result would be Collator::LESS ("abc" &lt;&lt;&lt; "ABC")
     * .       // (with tertiary difference between "abc" and "ABC")
     * .       result =  myCollation->compare(abc, 3, ABC, 3);
     * </pre>
     * @param source the source string array to be compared with.
     * @param sourceLength the length of the source string array. If this value
     *        is equal to -1, the string array is null-terminated.
     * @param target the string that is to be compared with the source string.
     * @param targetLength the length of the target string array. If this value
     *        is equal to -1, the string array is null-terminated.
     * @return Returns a byte value. GREATER if source is greater than target;
     *         EQUAL if source is equal to target; LESS if source is less than
     *         target
     * @deprecated ICU 2.6 Use overload with UErrorCode&
     */
    virtual EComparisonResult compare(const UChar* source, int32_t sourceLength,
                                      const UChar* target, int32_t targetLength)
                                      const;

    /**
    * The comparison function compares the character data stored in two
    * different string arrays. Returns information about whether a string array 
    * is less than, greater than or equal to another string array.
    * @param source the source string array to be compared with.
    * @param sourceLength the length of the source string array.  If this value
    *        is equal to -1, the string array is null-terminated.
    * @param target the string that is to be compared with the source string.
    * @param targetLength the length of the target string array.  If this value
    *        is equal to -1, the string array is null-terminated.
    * @param status possible error code
    * @return Returns an enum value. UCOL_GREATER if source is greater
    * than target; UCOL_EQUAL if source is equal to target; UCOL_LESS if source is less
    * than target
    * @stable ICU 2.6
    */
    virtual UCollationResult compare(const UChar* source, int32_t sourceLength,
                                      const UChar* target, int32_t targetLength,
                                      UErrorCode &status) const;

    /**
     * Compares two strings using the Collator.
     * Returns whether the first one compares less than/equal to/greater than
     * the second one.
     * This version takes UCharIterator input.
     * @param sIter the first ("source") string iterator
     * @param tIter the second ("target") string iterator
     * @param status ICU status
     * @return UCOL_LESS, UCOL_EQUAL or UCOL_GREATER
     * @stable ICU 4.2
     */
    virtual UCollationResult compare(UCharIterator &sIter,
                                     UCharIterator &tIter,
                                     UErrorCode &status) const;

    /**
    * Transforms a specified region of the string into a series of characters
    * that can be compared with CollationKey.compare. Use a CollationKey when
    * you need to do repeated comparisions on the same string. For a single
    * comparison the compare method will be faster.
    * @param source the source string.
    * @param key the transformed key of the source string.
    * @param status the error code status.
    * @return the transformed key.
    * @see CollationKey
    * @deprecated ICU 2.8 Use getSortKey(...) instead
    */
    virtual CollationKey& getCollationKey(const UnicodeString& source,
                                          CollationKey& key,
                                          UErrorCode& status) const;

    /**
    * Transforms a specified region of the string into a series of characters
    * that can be compared with CollationKey.compare. Use a CollationKey when
    * you need to do repeated comparisions on the same string. For a single
    * comparison the compare method will be faster.
    * @param source the source string.
    * @param sourceLength the length of the source string.
    * @param key the transformed key of the source string.
    * @param status the error code status.
    * @return the transformed key.
    * @see CollationKey
    * @deprecated ICU 2.8 Use getSortKey(...) instead
    */
    virtual CollationKey& getCollationKey(const UChar *source,
                                          int32_t sourceLength,
                                          CollationKey& key,
                                          UErrorCode& status) const;

    /**
     * Generates the hash code for the rule-based collation object.
     * @return the hash code.
     * @stable ICU 2.0
     */
    virtual int32_t hashCode(void) const;

    /**
    * Gets the locale of the Collator
    * @param type can be either requested, valid or actual locale. For more
    *             information see the definition of ULocDataLocaleType in
    *             uloc.h
    * @param status the error code status.
    * @return locale where the collation data lives. If the collator
    *         was instantiated from rules, locale is empty.
    * @deprecated ICU 2.8 likely to change in ICU 3.0, based on feedback
    */
    virtual const Locale getLocale(ULocDataLocaleType type, UErrorCode& status) const;

    /**
     * Gets the table-based rules for the collation object.
     * @return returns the collation rules that the table collation object was
     *         created from.
     * @stable ICU 2.0
     */
    const UnicodeString& getRules(void) const;

    /**
     * Gets the version information for a Collator.
     * @param info the version # information, the result will be filled in
     * @stable ICU 2.0
     */
    virtual void getVersion(UVersionInfo info) const;

    /**
     * Return the maximum length of any expansion sequences that end with the
     * specified comparison order.
     * @param order a collation order returned by previous or next.
     * @return maximum size of the expansion sequences ending with the collation
     *         element or 1 if collation element does not occur at the end of
     *         any expansion sequence
     * @see CollationElementIterator#getMaxExpansion
     * @stable ICU 2.0
     */
    int32_t getMaxExpansion(int32_t order) const;

    /**
     * Returns a unique class ID POLYMORPHICALLY. Pure virtual override. This
     * method is to implement a simple version of RTTI, since not all C++
     * compilers support genuine RTTI. Polymorphic operator==() and clone()
     * methods call this method.
     * @return The class ID for this object. All objects of a given class have
     *         the same class ID. Objects of other classes have different class
     *         IDs.
     * @stable ICU 2.0
     */
    virtual UClassID getDynamicClassID(void) const;

    /**
     * Returns the class ID for this class. This is useful only for comparing to
     * a return value from getDynamicClassID(). For example:
     * <pre>
     * Base* polymorphic_pointer = createPolymorphicObject();
     * if (polymorphic_pointer->getDynamicClassID() ==
     *                                          Derived::getStaticClassID()) ...
     * </pre>
     * @return The class ID for all objects of this class.
     * @stable ICU 2.0
     */
    static UClassID U_EXPORT2 getStaticClassID(void);

    /**
     * Returns the binary format of the class's rules. The format is that of
     * .col files.
     * @param length Returns the length of the data, in bytes
     * @param status the error code status.
     * @return memory, owned by the caller, of size 'length' bytes.
     * @stable ICU 2.2
     */
    uint8_t *cloneRuleData(int32_t &length, UErrorCode &status);


    /** Creates a binary image of a collator. This binary image can be stored and 
    *  later used to instantiate a collator using ucol_openBinary.
    *  This API supports preflighting.
    *  @param buffer a fill-in buffer to receive the binary image
    *  @param capacity capacity of the destination buffer
    *  @param status for catching errors
    *  @return size of the image
    *  @see ucol_openBinary
    *  @stable ICU 3.4
    */
    int32_t cloneBinary(uint8_t *buffer, int32_t capacity, UErrorCode &status);

    /**
     * Returns current rules. Delta defines whether full rules are returned or
     * just the tailoring.
     * @param delta one of UCOL_TAILORING_ONLY, UCOL_FULL_RULES.
     * @param buffer UnicodeString to store the result rules
     * @stable ICU 2.2
     */
    void getRules(UColRuleOption delta, UnicodeString &buffer);

    /**
     * Universal attribute setter
     * @param attr attribute type
     * @param value attribute value
     * @param status to indicate whether the operation went on smoothly or there were errors
     * @stable ICU 2.2
     */
    virtual void setAttribute(UColAttribute attr, UColAttributeValue value,
                              UErrorCode &status);

    /**
     * Universal attribute getter.
     * @param attr attribute type
     * @param status to indicate whether the operation went on smoothly or there were errors
     * @return attribute value
     * @stable ICU 2.2
     */
    virtual UColAttributeValue getAttribute(UColAttribute attr,
                                            UErrorCode &status);

    /**
     * Sets the variable top to a collation element value of a string supplied.
     * @param varTop one or more (if contraction) UChars to which the variable top should be set
     * @param len length of variable top string. If -1 it is considered to be zero terminated.
     * @param status error code. If error code is set, the return value is undefined. Errors set by this function are: <br>
     *    U_CE_NOT_FOUND_ERROR if more than one character was passed and there is no such a contraction<br>
     *    U_PRIMARY_TOO_LONG_ERROR if the primary for the variable top has more than two bytes
     * @return a 32 bit value containing the value of the variable top in upper 16 bits. Lower 16 bits are undefined
     * @stable ICU 2.0
     */
    virtual uint32_t setVariableTop(const UChar *varTop, int32_t len, UErrorCode &status);

    /**
     * Sets the variable top to a collation element value of a string supplied.
     * @param varTop an UnicodeString size 1 or more (if contraction) of UChars to which the variable top should be set
     * @param status error code. If error code is set, the return value is undefined. Errors set by this function are: <br>
     *    U_CE_NOT_FOUND_ERROR if more than one character was passed and there is no such a contraction<br>
     *    U_PRIMARY_TOO_LONG_ERROR if the primary for the variable top has more than two bytes
     * @return a 32 bit value containing the value of the variable top in upper 16 bits. Lower 16 bits are undefined
     * @stable ICU 2.0
     */
    virtual uint32_t setVariableTop(const UnicodeString varTop, UErrorCode &status);

    /**
     * Sets the variable top to a collation element value supplied. Variable top is set to the upper 16 bits.
     * Lower 16 bits are ignored.
     * @param varTop CE value, as returned by setVariableTop or ucol)getVariableTop
     * @param status error code (not changed by function)
     * @stable ICU 2.0
     */
    virtual void setVariableTop(const uint32_t varTop, UErrorCode &status);

    /**
     * Gets the variable top value of a Collator.
     * Lower 16 bits are undefined and should be ignored.
     * @param status error code (not changed by function). If error code is set, the return value is undefined.
     * @stable ICU 2.0
     */
    virtual uint32_t getVariableTop(UErrorCode &status) const;

    /**
     * Get an UnicodeSet that contains all the characters and sequences tailored in 
     * this collator.
     * @param status      error code of the operation
     * @return a pointer to a UnicodeSet object containing all the 
     *         code points and sequences that may sort differently than
     *         in the UCA. The object must be disposed of by using delete
     * @stable ICU 2.4
     */
    virtual UnicodeSet *getTailoredSet(UErrorCode &status) const;

    /**
     * Thread safe cloning operation.
     * @return pointer to the new clone, user should remove it.
     * @stable ICU 2.2
     */
    virtual Collator* safeClone(void);

    /**
     * Get the sort key as an array of bytes from an UnicodeString.
     * @param source string to be processed.
     * @param result buffer to store result in. If NULL, number of bytes needed
     *        will be returned.
     * @param resultLength length of the result buffer. If if not enough the
     *        buffer will be filled to capacity.
     * @return Number of bytes needed for storing the sort key
     * @stable ICU 2.0
     */
    virtual int32_t getSortKey(const UnicodeString& source, uint8_t *result,
                               int32_t resultLength) const;

    /**
     * Get the sort key as an array of bytes from an UChar buffer.
     * @param source string to be processed.
     * @param sourceLength length of string to be processed. If -1, the string
     *        is 0 terminated and length will be decided by the function.
     * @param result buffer to store result in. If NULL, number of bytes needed
     *        will be returned.
     * @param resultLength length of the result buffer. If if not enough the
     *        buffer will be filled to capacity.
     * @return Number of bytes needed for storing the sort key
     * @stable ICU 2.2
     */
    virtual int32_t getSortKey(const UChar *source, int32_t sourceLength,
                               uint8_t *result, int32_t resultLength) const;

    /**
    * Determines the minimum strength that will be use in comparison or
    * transformation.
    * <p>E.g. with strength == SECONDARY, the tertiary difference is ignored
    * <p>E.g. with strength == PRIMARY, the secondary and tertiary difference
    * are ignored.
    * @return the current comparison level.
    * @see RuleBasedCollator#setStrength
    * @deprecated ICU 2.6 Use getAttribute(UCOL_STRENGTH...) instead
    */
    virtual ECollationStrength getStrength(void) const;

    /**
    * Sets the minimum strength to be used in comparison or transformation.
    * @see RuleBasedCollator#getStrength
    * @param newStrength the new comparison level.
    * @deprecated ICU 2.6 Use setAttribute(UCOL_STRENGTH...) instead
    */
    virtual void setStrength(ECollationStrength newStrength);

    /**
     * Get the current reordering of scripts (if one has been set).
     * @param dest The array to fill with the script ordering.
     * @param destCapacity The length of dest. If it is 0, then dest may be NULL and the function will only return the length of the result without writing any of the result string (pre-flighting).
     * @param pErrorCode Must be a valid pointer to an error code value, which must not indicate a failure before the function call.
     * @return The length of the array of the script ordering.
     * @see ucol_getReorderCodes
     * @internal 
     */
    virtual int32_t getReorderCodes(int32_t* dest,
                                    int32_t destCapacity,
                                    UErrorCode& status) const;

    /**
     * Set the ordering of scripts for this collator.
     * @param reorderCodes An array of script codes in the new order.
     * @param reorderCodesLength The length of reorderCodes.
     * @see ucol_setReorderCodes
     * @internal 
     */
    virtual void setReorderCodes(const int32_t* reorderCodes,
                                 int32_t reorderCodesLength,
                                 UErrorCode& status);


private:

    // private static constants -----------------------------------------------

    enum {
        /* need look up in .commit() */
        CHARINDEX = 0x70000000,
        /* Expand index follows */
        EXPANDCHARINDEX = 0x7E000000,
        /* contract indexes follows */
        CONTRACTCHARINDEX = 0x7F000000,
        /* unmapped character values */
        UNMAPPED = 0xFFFFFFFF,
        /* primary strength increment */
        PRIMARYORDERINCREMENT = 0x00010000,
        /* secondary strength increment */
        SECONDARYORDERINCREMENT = 0x00000100,
        /* tertiary strength increment */
        TERTIARYORDERINCREMENT = 0x00000001,
        /* mask off anything but primary order */
        PRIMARYORDERMASK = 0xffff0000,
        /* mask off anything but secondary order */
        SECONDARYORDERMASK = 0x0000ff00,
        /* mask off anything but tertiary order */
        TERTIARYORDERMASK = 0x000000ff,
        /* mask off ignorable char order */
        IGNORABLEMASK = 0x0000ffff,
        /* use only the primary difference */
        PRIMARYDIFFERENCEONLY = 0xffff0000,
        /* use only the primary and secondary difference */
        SECONDARYDIFFERENCEONLY = 0xffffff00,
        /* primary order shift */
        PRIMARYORDERSHIFT = 16,
        /* secondary order shift */
        SECONDARYORDERSHIFT = 8,
        /* starting value for collation elements */
        COLELEMENTSTART = 0x02020202,
        /* testing mask for primary low element */
        PRIMARYLOWZEROMASK = 0x00FF0000,
        /* reseting value for secondaries and tertiaries */
        RESETSECONDARYTERTIARY = 0x00000202,
        /* reseting value for tertiaries */
        RESETTERTIARY = 0x00000002,

        PRIMIGNORABLE = 0x0202
    };

    // private data members ---------------------------------------------------

    UBool dataIsOwned;

    UBool isWriteThroughAlias;

    /**
    * c struct for collation. All initialisation for it has to be done through
    * setUCollator().
    */
    UCollator *ucollator;

    /**
    * Rule UnicodeString
    */
    UnicodeString urulestring;

    // friend classes --------------------------------------------------------

    /**
    * Used to iterate over collation elements in a character source.
    */
    friend class CollationElementIterator;

    /**
    * Collator ONLY needs access to RuleBasedCollator(const Locale&,
    *                                                       UErrorCode&)
    */
    friend class Collator;

    /**
    * Searching over collation elements in a character source
    */
    friend class StringSearch;

    // private constructors --------------------------------------------------

    /**
     * Default constructor
     */
    RuleBasedCollator();

    /**
     * RuleBasedCollator constructor. This constructor takes a locale. The
     * only caller of this class should be Collator::createInstance(). If
     * createInstance() happens to know that the requested locale's collation is
     * implemented as a RuleBasedCollator, it can then call this constructor.
     * OTHERWISE IT SHOULDN'T, since this constructor ALWAYS RETURNS A VALID
     * COLLATION TABLE. It does this by falling back to defaults.
     * @param desiredLocale locale used
     * @param status error code status
     */
    RuleBasedCollator(const Locale& desiredLocale, UErrorCode& status);

    /**
     * common constructor implementation
     *
     * @param rules the collation rules to build the collation table from.
     * @param collationStrength default strength for comparison
     * @param decompositionMode the normalisation mode
     * @param status reporting a success or an error.
     */
    void
    construct(const UnicodeString& rules,
              UColAttributeValue collationStrength,
              UColAttributeValue decompositionMode,
              UErrorCode& status);

    // private methods -------------------------------------------------------

    /**
    * Creates the c struct for ucollator
    * @param locale desired locale
    * @param status error status
    */
    void setUCollator(const Locale& locale, UErrorCode& status);

    /**
    * Creates the c struct for ucollator
    * @param locale desired locale name
    * @param status error status
    */
    void setUCollator(const char* locale, UErrorCode& status);

    /**
    * Creates the c struct for ucollator. This used internally by StringSearch.
    * Hence the responsibility of cleaning up the ucollator is not done by
    * this RuleBasedCollator. The isDataOwned flag is set to FALSE.
    * @param collator new ucollator data
    * @param rules corresponding collation rules
    */
    void setUCollator(UCollator *collator);

public:
    /**
    * Get UCollator data struct. Used only by StringSearch & intltest.
    * @return UCollator data struct
    * @internal
    */
    const UCollator * getUCollator();

protected:
   /**
    * Used internally by registraton to define the requested and valid locales.
    * @param requestedLocale the requsted locale
    * @param validLocale the valid locale
    * @param actualLocale the actual locale
    * @internal
    */
    virtual void setLocales(const Locale& requestedLocale, const Locale& validLocale, const Locale& actualLocale);

private:

    // if not owned and not a write through alias, copy the ucollator
    void checkOwned(void);

    // utility to init rule string used by checkOwned and construct
    void setRuleStringFromCollator();

    /**
    * Converts C's UCollationResult to EComparisonResult
    * @param result member of the enum UComparisonResult
    * @return EComparisonResult equivalent of UCollationResult
    * @deprecated ICU 2.6. We will not need it.
    */
    Collator::EComparisonResult getEComparisonResult(
                                            const UCollationResult &result) const;

    /**
    * Converts C's UCollationStrength to ECollationStrength
    * @param strength member of the enum UCollationStrength
    * @return ECollationStrength equivalent of UCollationStrength
    */
    Collator::ECollationStrength getECollationStrength(
                                        const UCollationStrength &strength) const;

    /**
    * Converts C++'s ECollationStrength to UCollationStrength
    * @param strength member of the enum ECollationStrength
    * @return UCollationStrength equivalent of ECollationStrength
    */
    UCollationStrength getUCollationStrength(
      const Collator::ECollationStrength &strength) const;
};

// inline method implementation ---------------------------------------------

inline void RuleBasedCollator::setUCollator(const Locale &locale,
                                               UErrorCode &status)
{
    setUCollator(locale.getName(), status);
}


inline void RuleBasedCollator::setUCollator(UCollator     *collator)
{

    if (ucollator && dataIsOwned) {
        ucol_close(ucollator);
    }
    ucollator   = collator;
    dataIsOwned = FALSE;
    isWriteThroughAlias = TRUE;
    setRuleStringFromCollator();
}

inline const UCollator * RuleBasedCollator::getUCollator()
{
    return ucollator;
}

inline Collator::EComparisonResult RuleBasedCollator::getEComparisonResult(
                                           const UCollationResult &result) const
{
    switch (result)
    {
    case UCOL_LESS :
        return Collator::LESS;
    case UCOL_EQUAL :
        return Collator::EQUAL;
    default :
        return Collator::GREATER;
    }
}

inline Collator::ECollationStrength RuleBasedCollator::getECollationStrength(
                                       const UCollationStrength &strength) const
{
    switch (strength)
    {
    case UCOL_PRIMARY :
        return Collator::PRIMARY;
    case UCOL_SECONDARY :
        return Collator::SECONDARY;
    case UCOL_TERTIARY :
        return Collator::TERTIARY;
    case UCOL_QUATERNARY :
        return Collator::QUATERNARY;
    default :
        return Collator::IDENTICAL;
    }
}

inline UCollationStrength RuleBasedCollator::getUCollationStrength(
                             const Collator::ECollationStrength &strength) const
{
    switch (strength)
    {
    case Collator::PRIMARY :
        return UCOL_PRIMARY;
    case Collator::SECONDARY :
        return UCOL_SECONDARY;
    case Collator::TERTIARY :
        return UCOL_TERTIARY;
    case Collator::QUATERNARY :
        return UCOL_QUATERNARY;
    default :
        return UCOL_IDENTICAL;
    }
}

U_NAMESPACE_END

#endif /* #if !UCONFIG_NO_COLLATION */

#endif