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      1 /*
      2 *******************************************************************************
      3 * Copyright (C) 2013-2014, International Business Machines
      4 * Corporation and others.  All Rights Reserved.
      5 *******************************************************************************
      6 * collationrootelements.h
      7 *
      8 * created on: 2013mar01
      9 * created by: Markus W. Scherer
     10 */
     11 
     12 #ifndef __COLLATIONROOTELEMENTS_H__
     13 #define __COLLATIONROOTELEMENTS_H__
     14 
     15 #include "unicode/utypes.h"
     16 
     17 #if !UCONFIG_NO_COLLATION
     18 
     19 #include "unicode/uobject.h"
     20 #include "collation.h"
     21 
     22 U_NAMESPACE_BEGIN
     23 
     24 /**
     25  * Container and access methods for collation elements and weights
     26  * that occur in the root collator.
     27  * Needed for finding boundaries for building a tailoring.
     28  *
     29  * This class takes and returns 16-bit secondary and tertiary weights.
     30  */
     31 class U_I18N_API CollationRootElements : public UMemory {
     32 public:
     33     CollationRootElements(const uint32_t *rootElements, int32_t rootElementsLength)
     34             : elements(rootElements), length(rootElementsLength) {}
     35 
     36     /**
     37      * Higher than any root primary.
     38      */
     39     static const uint32_t PRIMARY_SENTINEL = 0xffffff00;
     40 
     41     /**
     42      * Flag in a root element, set if the element contains secondary & tertiary weights,
     43      * rather than a primary.
     44      */
     45     static const uint32_t SEC_TER_DELTA_FLAG = 0x80;
     46     /**
     47      * Mask for getting the primary range step value from a primary-range-end element.
     48      */
     49     static const uint8_t PRIMARY_STEP_MASK = 0x7f;
     50 
     51     enum {
     52         /**
     53          * Index of the first CE with a non-zero tertiary weight.
     54          * Same as the start of the compact root elements table.
     55          */
     56         IX_FIRST_TERTIARY_INDEX,
     57         /**
     58          * Index of the first CE with a non-zero secondary weight.
     59          */
     60         IX_FIRST_SECONDARY_INDEX,
     61         /**
     62          * Index of the first CE with a non-zero primary weight.
     63          */
     64         IX_FIRST_PRIMARY_INDEX,
     65         /**
     66          * Must match Collation::COMMON_SEC_AND_TER_CE.
     67          */
     68         IX_COMMON_SEC_AND_TER_CE,
     69         /**
     70          * Secondary & tertiary boundaries.
     71          * Bits 31..24: [fixed last secondary common byte 45]
     72          * Bits 23..16: [fixed first ignorable secondary byte 80]
     73          * Bits 15.. 8: reserved, 0
     74          * Bits  7.. 0: [fixed first ignorable tertiary byte 3C]
     75          */
     76         IX_SEC_TER_BOUNDARIES,
     77         /**
     78          * The current number of indexes.
     79          * Currently the same as elements[IX_FIRST_TERTIARY_INDEX].
     80          */
     81         IX_COUNT
     82     };
     83 
     84     /**
     85      * Returns the boundary between tertiary weights of primary/secondary CEs
     86      * and those of tertiary CEs.
     87      * This is the upper limit for tertiaries of primary/secondary CEs.
     88      * This minus one is the lower limit for tertiaries of tertiary CEs.
     89      */
     90     uint32_t getTertiaryBoundary() const {
     91         return (elements[IX_SEC_TER_BOUNDARIES] << 8) & 0xff00;
     92     }
     93 
     94     /**
     95      * Returns the first assigned tertiary CE.
     96      */
     97     uint32_t getFirstTertiaryCE() const {
     98         return elements[elements[IX_FIRST_TERTIARY_INDEX]] & ~SEC_TER_DELTA_FLAG;
     99     }
    100 
    101     /**
    102      * Returns the last assigned tertiary CE.
    103      */
    104     uint32_t getLastTertiaryCE() const {
    105         return elements[elements[IX_FIRST_SECONDARY_INDEX] - 1] & ~SEC_TER_DELTA_FLAG;
    106     }
    107 
    108     /**
    109      * Returns the last common secondary weight.
    110      * This is the lower limit for secondaries of primary CEs.
    111      */
    112     uint32_t getLastCommonSecondary() const {
    113         return (elements[IX_SEC_TER_BOUNDARIES] >> 16) & 0xff00;
    114     }
    115 
    116     /**
    117      * Returns the boundary between secondary weights of primary CEs
    118      * and those of secondary CEs.
    119      * This is the upper limit for secondaries of primary CEs.
    120      * This minus one is the lower limit for secondaries of secondary CEs.
    121      */
    122     uint32_t getSecondaryBoundary() const {
    123         return (elements[IX_SEC_TER_BOUNDARIES] >> 8) & 0xff00;
    124     }
    125 
    126     /**
    127      * Returns the first assigned secondary CE.
    128      */
    129     uint32_t getFirstSecondaryCE() const {
    130         return elements[elements[IX_FIRST_SECONDARY_INDEX]] & ~SEC_TER_DELTA_FLAG;
    131     }
    132 
    133     /**
    134      * Returns the last assigned secondary CE.
    135      */
    136     uint32_t getLastSecondaryCE() const {
    137         return elements[elements[IX_FIRST_PRIMARY_INDEX] - 1] & ~SEC_TER_DELTA_FLAG;
    138     }
    139 
    140     /**
    141      * Returns the first assigned primary weight.
    142      */
    143     uint32_t getFirstPrimary() const {
    144         return elements[elements[IX_FIRST_PRIMARY_INDEX]];  // step=0: cannot be a range end
    145     }
    146 
    147     /**
    148      * Returns the first assigned primary CE.
    149      */
    150     int64_t getFirstPrimaryCE() const {
    151         return Collation::makeCE(getFirstPrimary());
    152     }
    153 
    154     /**
    155      * Returns the last root CE with a primary weight before p.
    156      * Intended only for reordering group boundaries.
    157      */
    158     int64_t lastCEWithPrimaryBefore(uint32_t p) const;
    159 
    160     /**
    161      * Returns the first root CE with a primary weight of at least p.
    162      * Intended only for reordering group boundaries.
    163      */
    164     int64_t firstCEWithPrimaryAtLeast(uint32_t p) const;
    165 
    166     /**
    167      * Returns the primary weight before p.
    168      * p must be greater than the first root primary.
    169      */
    170     uint32_t getPrimaryBefore(uint32_t p, UBool isCompressible) const;
    171 
    172     /** Returns the secondary weight before [p, s]. */
    173     uint32_t getSecondaryBefore(uint32_t p, uint32_t s) const;
    174 
    175     /** Returns the tertiary weight before [p, s, t]. */
    176     uint32_t getTertiaryBefore(uint32_t p, uint32_t s, uint32_t t) const;
    177 
    178     /**
    179      * Finds the index of the input primary.
    180      * p must occur as a root primary, and must not be 0.
    181      */
    182     int32_t findPrimary(uint32_t p) const;
    183 
    184     /**
    185      * Returns the primary weight after p where index=findPrimary(p).
    186      * p must be at least the first root primary.
    187      */
    188     uint32_t getPrimaryAfter(uint32_t p, int32_t index, UBool isCompressible) const;
    189     /**
    190      * Returns the secondary weight after [p, s] where index=findPrimary(p)
    191      * except use index=0 for p=0.
    192      */
    193     uint32_t getSecondaryAfter(int32_t index, uint32_t s) const;
    194     /**
    195      * Returns the tertiary weight after [p, s, t] where index=findPrimary(p)
    196      * except use index=0 for p=0.
    197      */
    198     uint32_t getTertiaryAfter(int32_t index, uint32_t s, uint32_t t) const;
    199 
    200 private:
    201     /**
    202      * Finds the largest index i where elements[i]<=p.
    203      * Requires first primary<=p<0xffffff00 (PRIMARY_SENTINEL).
    204      * Does not require that p is a root collator primary.
    205      */
    206     int32_t findP(uint32_t p) const;
    207 
    208     static inline UBool isEndOfPrimaryRange(uint32_t q) {
    209         return (q & SEC_TER_DELTA_FLAG) == 0 && (q & PRIMARY_STEP_MASK) != 0;
    210     }
    211 
    212     /**
    213      * Data structure:
    214      *
    215      * The first few entries are indexes, up to elements[IX_FIRST_TERTIARY_INDEX].
    216      * See the comments on the IX_ constants.
    217      *
    218      * All other elements are a compact form of the root collator CEs
    219      * in collation order.
    220      *
    221      * Primary weights have the SEC_TER_DELTA_FLAG flag not set.
    222      * A primary-weight element by itself represents a root CE
    223      * with Collation::COMMON_SEC_AND_TER_CE.
    224      *
    225      * If there are root CEs with the same primary but other secondary/tertiary weights,
    226      * then for each such CE there is an element with those secondary and tertiary weights,
    227      * and with the SEC_TER_DELTA_FLAG flag set.
    228      *
    229      * A range of only-primary CEs with a consistent "step" increment
    230      * from each primary to the next may be stored as a range.
    231      * Only the first and last primary are stored, and the last has the step
    232      * value in the low bits (PRIMARY_STEP_MASK).
    233      *
    234      * An range-end element may also either start a new range or be followed by
    235      * elements with secondary/tertiary deltas.
    236      *
    237      * A primary element that is not a range end has zero step bits.
    238      *
    239      * There is no element for the completely ignorable CE (all weights 0).
    240      *
    241      * Before elements[IX_FIRST_PRIMARY_INDEX], all elements are secondary/tertiary deltas,
    242      * for all of the ignorable root CEs.
    243      *
    244      * There are no elements for unassigned-implicit primary CEs.
    245      * All primaries stored here are at most 3 bytes long.
    246      */
    247     const uint32_t *elements;
    248     int32_t length;
    249 };
    250 
    251 U_NAMESPACE_END
    252 
    253 #endif  // !UCONFIG_NO_COLLATION
    254 #endif  // __COLLATIONROOTELEMENTS_H__
    255