168 lines
6.5 KiB
C++
168 lines
6.5 KiB
C++
/*
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*******************************************************************************
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* Copyright (C) 2012-2014, International Business Machines
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* Corporation and others. All Rights Reserved.
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*******************************************************************************
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* collationkeys.h
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*
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* created on: 2012sep02
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* created by: Markus W. Scherer
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*/
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#ifndef __COLLATIONKEYS_H__
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#define __COLLATIONKEYS_H__
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#include "unicode/utypes.h"
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#if !UCONFIG_NO_COLLATION
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#include "unicode/bytestream.h"
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#include "unicode/ucol.h"
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#include "charstr.h"
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#include "collation.h"
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U_NAMESPACE_BEGIN
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class CollationIterator;
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struct CollationDataReader;
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struct CollationSettings;
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class SortKeyByteSink : public ByteSink {
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public:
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SortKeyByteSink(char *dest, int32_t destCapacity)
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: buffer_(dest), capacity_(destCapacity),
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appended_(0), ignore_(0) {}
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virtual ~SortKeyByteSink();
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void IgnoreBytes(int32_t numIgnore) { ignore_ = numIgnore; }
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virtual void Append(const char *bytes, int32_t n);
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void Append(uint32_t b) {
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if (ignore_ > 0) {
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--ignore_;
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} else {
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if (appended_ < capacity_ || Resize(1, appended_)) {
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buffer_[appended_] = (char)b;
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}
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++appended_;
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}
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}
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virtual char *GetAppendBuffer(int32_t min_capacity,
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int32_t desired_capacity_hint,
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char *scratch, int32_t scratch_capacity,
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int32_t *result_capacity);
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int32_t NumberOfBytesAppended() const { return appended_; }
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/**
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* @return how many bytes can be appended (including ignored ones)
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* without reallocation
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*/
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int32_t GetRemainingCapacity() const {
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// Either ignore_ or appended_ should be 0.
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return ignore_ + capacity_ - appended_;
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}
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UBool Overflowed() const { return appended_ > capacity_; }
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/** @return FALSE if memory allocation failed */
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UBool IsOk() const { return buffer_ != NULL; }
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protected:
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virtual void AppendBeyondCapacity(const char *bytes, int32_t n, int32_t length) = 0;
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virtual UBool Resize(int32_t appendCapacity, int32_t length) = 0;
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void SetNotOk() {
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buffer_ = NULL;
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capacity_ = 0;
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}
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char *buffer_;
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int32_t capacity_;
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int32_t appended_;
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int32_t ignore_;
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private:
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SortKeyByteSink(const SortKeyByteSink &); // copy constructor not implemented
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SortKeyByteSink &operator=(const SortKeyByteSink &); // assignment operator not implemented
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};
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class U_I18N_API CollationKeys /* not : public UObject because all methods are static */ {
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public:
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class LevelCallback : public UMemory {
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public:
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virtual ~LevelCallback();
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/**
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* @param level The next level about to be written to the ByteSink.
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* @return TRUE if the level is to be written
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* (the base class implementation always returns TRUE)
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*/
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virtual UBool needToWrite(Collation::Level level);
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};
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/**
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* Writes the sort key bytes for minLevel up to the iterator data's strength.
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* Optionally writes the case level.
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* Stops writing levels when callback.needToWrite(level) returns FALSE.
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* Separates levels with the LEVEL_SEPARATOR_BYTE
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* but does not write a TERMINATOR_BYTE.
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*/
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static void writeSortKeyUpToQuaternary(CollationIterator &iter,
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const UBool *compressibleBytes,
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const CollationSettings &settings,
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SortKeyByteSink &sink,
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Collation::Level minLevel, LevelCallback &callback,
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UBool preflight, UErrorCode &errorCode);
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private:
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friend struct CollationDataReader;
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CollationKeys(); // no instantiation
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// Secondary level: Compress up to 33 common weights as 05..25 or 25..45.
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static const uint32_t SEC_COMMON_LOW = Collation::COMMON_BYTE;
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static const uint32_t SEC_COMMON_MIDDLE = SEC_COMMON_LOW + 0x20;
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static const uint32_t SEC_COMMON_HIGH = SEC_COMMON_LOW + 0x40;
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static const int32_t SEC_COMMON_MAX_COUNT = 0x21;
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// Case level, lowerFirst: Compress up to 7 common weights as 1..7 or 7..13.
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static const uint32_t CASE_LOWER_FIRST_COMMON_LOW = 1;
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static const uint32_t CASE_LOWER_FIRST_COMMON_MIDDLE = 7;
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static const uint32_t CASE_LOWER_FIRST_COMMON_HIGH = 13;
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static const int32_t CASE_LOWER_FIRST_COMMON_MAX_COUNT = 7;
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// Case level, upperFirst: Compress up to 13 common weights as 3..15.
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static const uint32_t CASE_UPPER_FIRST_COMMON_LOW = 3;
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static const uint32_t CASE_UPPER_FIRST_COMMON_HIGH = 15;
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static const int32_t CASE_UPPER_FIRST_COMMON_MAX_COUNT = 13;
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// Tertiary level only (no case): Compress up to 97 common weights as 05..65 or 65..C5.
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static const uint32_t TER_ONLY_COMMON_LOW = Collation::COMMON_BYTE;
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static const uint32_t TER_ONLY_COMMON_MIDDLE = TER_ONLY_COMMON_LOW + 0x60;
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static const uint32_t TER_ONLY_COMMON_HIGH = TER_ONLY_COMMON_LOW + 0xc0;
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static const int32_t TER_ONLY_COMMON_MAX_COUNT = 0x61;
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// Tertiary with case, lowerFirst: Compress up to 33 common weights as 05..25 or 25..45.
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static const uint32_t TER_LOWER_FIRST_COMMON_LOW = Collation::COMMON_BYTE;
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static const uint32_t TER_LOWER_FIRST_COMMON_MIDDLE = TER_LOWER_FIRST_COMMON_LOW + 0x20;
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static const uint32_t TER_LOWER_FIRST_COMMON_HIGH = TER_LOWER_FIRST_COMMON_LOW + 0x40;
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static const int32_t TER_LOWER_FIRST_COMMON_MAX_COUNT = 0x21;
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// Tertiary with case, upperFirst: Compress up to 33 common weights as 85..A5 or A5..C5.
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static const uint32_t TER_UPPER_FIRST_COMMON_LOW = Collation::COMMON_BYTE + 0x80;
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static const uint32_t TER_UPPER_FIRST_COMMON_MIDDLE = TER_UPPER_FIRST_COMMON_LOW + 0x20;
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static const uint32_t TER_UPPER_FIRST_COMMON_HIGH = TER_UPPER_FIRST_COMMON_LOW + 0x40;
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static const int32_t TER_UPPER_FIRST_COMMON_MAX_COUNT = 0x21;
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// Quaternary level: Compress up to 113 common weights as 1C..8C or 8C..FC.
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static const uint32_t QUAT_COMMON_LOW = 0x1c;
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static const uint32_t QUAT_COMMON_MIDDLE = QUAT_COMMON_LOW + 0x70;
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static const uint32_t QUAT_COMMON_HIGH = QUAT_COMMON_LOW + 0xE0;
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static const int32_t QUAT_COMMON_MAX_COUNT = 0x71;
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// Primary weights shifted to quaternary level must be encoded with
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// a lead byte below the common-weight compression range.
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static const uint32_t QUAT_SHIFTED_LIMIT_BYTE = QUAT_COMMON_LOW - 1; // 0x1b
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};
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U_NAMESPACE_END
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#endif // !UCONFIG_NO_COLLATION
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#endif // __COLLATIONKEYS_H__
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