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      1 // Copyright (C) 2016 and later: Unicode, Inc. and others.
      2 // License & terms of use: http://www.unicode.org/copyright.html
      3 /*
      4 *******************************************************************************
      5 * Copyright (C) 2012-2014, International Business Machines
      6 * Corporation and others.  All Rights Reserved.
      7 *******************************************************************************
      8 * collationkeys.h
      9 *
     10 * created on: 2012sep02
     11 * created by: Markus W. Scherer
     12 */
     13 
     14 #ifndef __COLLATIONKEYS_H__
     15 #define __COLLATIONKEYS_H__
     16 
     17 #include "unicode/utypes.h"
     18 
     19 #if !UCONFIG_NO_COLLATION
     20 
     21 #include "unicode/bytestream.h"
     22 #include "unicode/ucol.h"
     23 #include "charstr.h"
     24 #include "collation.h"
     25 
     26 U_NAMESPACE_BEGIN
     27 
     28 class CollationIterator;
     29 struct CollationDataReader;
     30 struct CollationSettings;
     31 
     32 class SortKeyByteSink : public ByteSink {
     33 public:
     34     SortKeyByteSink(char *dest, int32_t destCapacity)
     35             : buffer_(dest), capacity_(destCapacity),
     36               appended_(0), ignore_(0) {}
     37     virtual ~SortKeyByteSink();
     38 
     39     void IgnoreBytes(int32_t numIgnore) { ignore_ = numIgnore; }
     40 
     41     virtual void Append(const char *bytes, int32_t n);
     42     void Append(uint32_t b) {
     43         if (ignore_ > 0) {
     44             --ignore_;
     45         } else {
     46             if (appended_ < capacity_ || Resize(1, appended_)) {
     47                 buffer_[appended_] = (char)b;
     48             }
     49             ++appended_;
     50         }
     51     }
     52     virtual char *GetAppendBuffer(int32_t min_capacity,
     53                                   int32_t desired_capacity_hint,
     54                                   char *scratch, int32_t scratch_capacity,
     55                                   int32_t *result_capacity);
     56     int32_t NumberOfBytesAppended() const { return appended_; }
     57 
     58     /**
     59      * @return how many bytes can be appended (including ignored ones)
     60      *         without reallocation
     61      */
     62     int32_t GetRemainingCapacity() const {
     63         // Either ignore_ or appended_ should be 0.
     64         return ignore_ + capacity_ - appended_;
     65     }
     66 
     67     UBool Overflowed() const { return appended_ > capacity_; }
     68     /** @return FALSE if memory allocation failed */
     69     UBool IsOk() const { return buffer_ != NULL; }
     70 
     71 protected:
     72     virtual void AppendBeyondCapacity(const char *bytes, int32_t n, int32_t length) = 0;
     73     virtual UBool Resize(int32_t appendCapacity, int32_t length) = 0;
     74 
     75     void SetNotOk() {
     76         buffer_ = NULL;
     77         capacity_ = 0;
     78     }
     79 
     80     char *buffer_;
     81     int32_t capacity_;
     82     int32_t appended_;
     83     int32_t ignore_;
     84 
     85 private:
     86     SortKeyByteSink(const SortKeyByteSink &); // copy constructor not implemented
     87     SortKeyByteSink &operator=(const SortKeyByteSink &); // assignment operator not implemented
     88 };
     89 
     90 class U_I18N_API CollationKeys /* not : public UObject because all methods are static */ {
     91 public:
     92     class LevelCallback : public UMemory {
     93     public:
     94         virtual ~LevelCallback();
     95         /**
     96          * @param level The next level about to be written to the ByteSink.
     97          * @return TRUE if the level is to be written
     98          *         (the base class implementation always returns TRUE)
     99          */
    100         virtual UBool needToWrite(Collation::Level level);
    101     };
    102 
    103     /**
    104      * Writes the sort key bytes for minLevel up to the iterator data's strength.
    105      * Optionally writes the case level.
    106      * Stops writing levels when callback.needToWrite(level) returns FALSE.
    107      * Separates levels with the LEVEL_SEPARATOR_BYTE
    108      * but does not write a TERMINATOR_BYTE.
    109      */
    110     static void writeSortKeyUpToQuaternary(CollationIterator &iter,
    111                                            const UBool *compressibleBytes,
    112                                            const CollationSettings &settings,
    113                                            SortKeyByteSink &sink,
    114                                            Collation::Level minLevel, LevelCallback &callback,
    115                                            UBool preflight, UErrorCode &errorCode);
    116 private:
    117     friend struct CollationDataReader;
    118 
    119     CollationKeys();  // no instantiation
    120 
    121     // Secondary level: Compress up to 33 common weights as 05..25 or 25..45.
    122     static const uint32_t SEC_COMMON_LOW = Collation::COMMON_BYTE;
    123     static const uint32_t SEC_COMMON_MIDDLE = SEC_COMMON_LOW + 0x20;
    124     static const uint32_t SEC_COMMON_HIGH = SEC_COMMON_LOW + 0x40;
    125     static const int32_t SEC_COMMON_MAX_COUNT = 0x21;
    126 
    127     // Case level, lowerFirst: Compress up to 7 common weights as 1..7 or 7..13.
    128     static const uint32_t CASE_LOWER_FIRST_COMMON_LOW = 1;
    129     static const uint32_t CASE_LOWER_FIRST_COMMON_MIDDLE = 7;
    130     static const uint32_t CASE_LOWER_FIRST_COMMON_HIGH = 13;
    131     static const int32_t CASE_LOWER_FIRST_COMMON_MAX_COUNT = 7;
    132 
    133     // Case level, upperFirst: Compress up to 13 common weights as 3..15.
    134     static const uint32_t CASE_UPPER_FIRST_COMMON_LOW = 3;
    135     static const uint32_t CASE_UPPER_FIRST_COMMON_HIGH = 15;
    136     static const int32_t CASE_UPPER_FIRST_COMMON_MAX_COUNT = 13;
    137 
    138     // Tertiary level only (no case): Compress up to 97 common weights as 05..65 or 65..C5.
    139     static const uint32_t TER_ONLY_COMMON_LOW = Collation::COMMON_BYTE;
    140     static const uint32_t TER_ONLY_COMMON_MIDDLE = TER_ONLY_COMMON_LOW + 0x60;
    141     static const uint32_t TER_ONLY_COMMON_HIGH = TER_ONLY_COMMON_LOW + 0xc0;
    142     static const int32_t TER_ONLY_COMMON_MAX_COUNT = 0x61;
    143 
    144     // Tertiary with case, lowerFirst: Compress up to 33 common weights as 05..25 or 25..45.
    145     static const uint32_t TER_LOWER_FIRST_COMMON_LOW = Collation::COMMON_BYTE;
    146     static const uint32_t TER_LOWER_FIRST_COMMON_MIDDLE = TER_LOWER_FIRST_COMMON_LOW + 0x20;
    147     static const uint32_t TER_LOWER_FIRST_COMMON_HIGH = TER_LOWER_FIRST_COMMON_LOW + 0x40;
    148     static const int32_t TER_LOWER_FIRST_COMMON_MAX_COUNT = 0x21;
    149 
    150     // Tertiary with case, upperFirst: Compress up to 33 common weights as 85..A5 or A5..C5.
    151     static const uint32_t TER_UPPER_FIRST_COMMON_LOW = Collation::COMMON_BYTE + 0x80;
    152     static const uint32_t TER_UPPER_FIRST_COMMON_MIDDLE = TER_UPPER_FIRST_COMMON_LOW + 0x20;
    153     static const uint32_t TER_UPPER_FIRST_COMMON_HIGH = TER_UPPER_FIRST_COMMON_LOW + 0x40;
    154     static const int32_t TER_UPPER_FIRST_COMMON_MAX_COUNT = 0x21;
    155 
    156     // Quaternary level: Compress up to 113 common weights as 1C..8C or 8C..FC.
    157     static const uint32_t QUAT_COMMON_LOW = 0x1c;
    158     static const uint32_t QUAT_COMMON_MIDDLE = QUAT_COMMON_LOW + 0x70;
    159     static const uint32_t QUAT_COMMON_HIGH = QUAT_COMMON_LOW + 0xE0;
    160     static const int32_t QUAT_COMMON_MAX_COUNT = 0x71;
    161     // Primary weights shifted to quaternary level must be encoded with
    162     // a lead byte below the common-weight compression range.
    163     static const uint32_t QUAT_SHIFTED_LIMIT_BYTE = QUAT_COMMON_LOW - 1;  // 0x1b
    164 };
    165 
    166 U_NAMESPACE_END
    167 
    168 #endif  // !UCONFIG_NO_COLLATION
    169 #endif  // __COLLATIONKEYS_H__
    170