icuSources/i18n/collationkeys.h

   1 // © 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__