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+// Copyright (C) 2016 and later: Unicode, Inc. and others.
+// License & terms of use: http://www.unicode.org/copyright.html
+/*
+*******************************************************************************
+* Copyright (C) 2010-2014, International Business Machines
+* Corporation and others. All Rights Reserved.
+*******************************************************************************
+* collationiterator.h
+*
+* created on: 2010oct27
+* created by: Markus W. Scherer
+*/
+
+#ifndef __COLLATIONITERATOR_H__
+#define __COLLATIONITERATOR_H__
+
+#include "unicode/utypes.h"
+
+#if !UCONFIG_NO_COLLATION
+
+#include "cmemory.h"
+#include "collation.h"
+#include "collationdata.h"
+
+U_NAMESPACE_BEGIN
+
+class SkippedState;
+class UCharsTrie;
+class UVector32;
+
+/**
+ * Collation element iterator and abstract character iterator.
+ *
+ * When a method returns a code point value, it must be in 0..10FFFF,
+ * except it can be negative as a sentinel value.
+ */
+class U_I18N_API CollationIterator : public UObject {
+private:
+ class CEBuffer {
+ private:
+ /** Large enough for CEs of most short strings. */
+ static const int32_t INITIAL_CAPACITY = 40;
+ public:
+ CEBuffer() : length(0) {}
+ ~CEBuffer();
+
+ inline void append(int64_t ce, UErrorCode &errorCode) {
+ if(length < INITIAL_CAPACITY || ensureAppendCapacity(1, errorCode)) {
+ buffer[length++] = ce;
+ }
+ }
+
+ inline void appendUnsafe(int64_t ce) {
+ buffer[length++] = ce;
+ }
+
+ UBool ensureAppendCapacity(int32_t appCap, UErrorCode &errorCode);
+
+ inline UBool incLength(UErrorCode &errorCode) {
+ // Use INITIAL_CAPACITY for a very simple fastpath.
+ // (Rather than buffer.getCapacity().)
+ if(length < INITIAL_CAPACITY || ensureAppendCapacity(1, errorCode)) {
+ ++length;
+ return TRUE;
+ } else {
+ return FALSE;
+ }
+ }
+
+ inline int64_t set(int32_t i, int64_t ce) {
+ return buffer[i] = ce;
+ }
+ inline int64_t get(int32_t i) const { return buffer[i]; }
+
+ const int64_t *getCEs() const { return buffer.getAlias(); }
+
+ int32_t length;
+
+ private:
+ CEBuffer(const CEBuffer &);
+ void operator=(const CEBuffer &);
+
+ MaybeStackArray<int64_t, INITIAL_CAPACITY> buffer;
+ };
+
+public:
+ CollationIterator(const CollationData *d, UBool numeric)
+ : trie(d->trie),
+ data(d),
+ cesIndex(0),
+ skipped(NULL),
+ numCpFwd(-1),
+ isNumeric(numeric) {}
+
+ virtual ~CollationIterator();
+
+ virtual UBool operator==(const CollationIterator &other) const;
+ inline UBool operator!=(const CollationIterator &other) const {
+ return !operator==(other);
+ }
+
+ /**
+ * Resets the iterator state and sets the position to the specified offset.
+ * Subclasses must implement, and must call the parent class method,
+ * or CollationIterator::reset().
+ */
+ virtual void resetToOffset(int32_t newOffset) = 0;
+
+ virtual int32_t getOffset() const = 0;
+
+ /**
+ * Returns the next collation element.
+ */
+ inline int64_t nextCE(UErrorCode &errorCode) {
+ if(cesIndex < ceBuffer.length) {
+ // Return the next buffered CE.
+ return ceBuffer.get(cesIndex++);
+ }
+ // assert cesIndex == ceBuffer.length;
+ if(!ceBuffer.incLength(errorCode)) {
+ return Collation::NO_CE;
+ }
+ UChar32 c;
+ uint32_t ce32 = handleNextCE32(c, errorCode);
+ uint32_t t = ce32 & 0xff;
+ if(t < Collation::SPECIAL_CE32_LOW_BYTE) { // Forced-inline of isSpecialCE32(ce32).
+ // Normal CE from the main data.
+ // Forced-inline of ceFromSimpleCE32(ce32).
+ return ceBuffer.set(cesIndex++,
+ ((int64_t)(ce32 & 0xffff0000) << 32) | ((ce32 & 0xff00) << 16) | (t << 8));
+ }
+ const CollationData *d;
+ // The compiler should be able to optimize the previous and the following
+ // comparisons of t with the same constant.
+ if(t == Collation::SPECIAL_CE32_LOW_BYTE) {
+ if(c < 0) {
+ return ceBuffer.set(cesIndex++, Collation::NO_CE);
+ }
+ d = data->base;
+ ce32 = d->getCE32(c);
+ t = ce32 & 0xff;
+ if(t < Collation::SPECIAL_CE32_LOW_BYTE) {
+ // Normal CE from the base data.
+ return ceBuffer.set(cesIndex++,
+ ((int64_t)(ce32 & 0xffff0000) << 32) | ((ce32 & 0xff00) << 16) | (t << 8));
+ }
+ } else {
+ d = data;
+ }
+ if(t == Collation::LONG_PRIMARY_CE32_LOW_BYTE) {
+ // Forced-inline of ceFromLongPrimaryCE32(ce32).
+ return ceBuffer.set(cesIndex++,
+ ((int64_t)(ce32 - t) << 32) | Collation::COMMON_SEC_AND_TER_CE);
+ }
+ return nextCEFromCE32(d, c, ce32, errorCode);
+ }
+
+ /**
+ * Fetches all CEs.
+ * @return getCEsLength()
+ */
+ int32_t fetchCEs(UErrorCode &errorCode);
+
+ /**
+ * Overwrites the current CE (the last one returned by nextCE()).
+ */
+ void setCurrentCE(int64_t ce) {
+ // assert cesIndex > 0;
+ ceBuffer.set(cesIndex - 1, ce);
+ }
+
+ /**
+ * Returns the previous collation element.
+ */
+ int64_t previousCE(UVector32 &offsets, UErrorCode &errorCode);
+
+ inline int32_t getCEsLength() const {
+ return ceBuffer.length;
+ }
+
+ inline int64_t getCE(int32_t i) const {
+ return ceBuffer.get(i);
+ }
+
+ const int64_t *getCEs() const {
+ return ceBuffer.getCEs();
+ }
+
+ void clearCEs() {
+ cesIndex = ceBuffer.length = 0;
+ }
+
+ void clearCEsIfNoneRemaining() {
+ if(cesIndex == ceBuffer.length) { clearCEs(); }
+ }
+
+ /**
+ * Returns the next code point (with post-increment).
+ * Public for identical-level comparison and for testing.
+ */
+ virtual UChar32 nextCodePoint(UErrorCode &errorCode) = 0;
+
+ /**
+ * Returns the previous code point (with pre-decrement).
+ * Public for identical-level comparison and for testing.
+ */
+ virtual UChar32 previousCodePoint(UErrorCode &errorCode) = 0;
+
+protected:
+ CollationIterator(const CollationIterator &other);
+
+ void reset();
+
+ /**
+ * Returns the next code point and its local CE32 value.
+ * Returns Collation::FALLBACK_CE32 at the end of the text (c<0)
+ * or when c's CE32 value is to be looked up in the base data (fallback).
+ *
+ * The code point is used for fallbacks, context and implicit weights.
+ * It is ignored when the returned CE32 is not special (e.g., FFFD_CE32).
+ */
+ virtual uint32_t handleNextCE32(UChar32 &c, UErrorCode &errorCode);
+
+ /**
+ * Called when handleNextCE32() returns a LEAD_SURROGATE_TAG for a lead surrogate code unit.
+ * Returns the trail surrogate in that case and advances past it,
+ * if a trail surrogate follows the lead surrogate.
+ * Otherwise returns any other code unit and does not advance.
+ */
+ virtual UChar handleGetTrailSurrogate();
+
+ /**
+ * Called when handleNextCE32() returns with c==0, to see whether it is a NUL terminator.
+ * (Not needed in Java.)
+ */
+ virtual UBool foundNULTerminator();
+
+ /**
+ * @return FALSE if surrogate code points U+D800..U+DFFF
+ * map to their own implicit primary weights (for UTF-16),
+ * or TRUE if they map to CE(U+FFFD) (for UTF-8)
+ */
+ virtual UBool forbidSurrogateCodePoints() const;
+
+ virtual void forwardNumCodePoints(int32_t num, UErrorCode &errorCode) = 0;
+
+ virtual void backwardNumCodePoints(int32_t num, UErrorCode &errorCode) = 0;
+
+ /**
+ * Returns the CE32 from the data trie.
+ * Normally the same as data->getCE32(), but overridden in the builder.
+ * Call this only when the faster data->getCE32() cannot be used.
+ */
+ virtual uint32_t getDataCE32(UChar32 c) const;
+
+ virtual uint32_t getCE32FromBuilderData(uint32_t ce32, UErrorCode &errorCode);
+
+ void appendCEsFromCE32(const CollationData *d, UChar32 c, uint32_t ce32,
+ UBool forward, UErrorCode &errorCode);
+
+ // Main lookup trie of the data object.
+ const UTrie2 *trie;
+ const CollationData *data;
+
+private:
+ int64_t nextCEFromCE32(const CollationData *d, UChar32 c, uint32_t ce32,
+ UErrorCode &errorCode);
+
+ uint32_t getCE32FromPrefix(const CollationData *d, uint32_t ce32,
+ UErrorCode &errorCode);
+
+ UChar32 nextSkippedCodePoint(UErrorCode &errorCode);
+
+ void backwardNumSkipped(int32_t n, UErrorCode &errorCode);
+
+ uint32_t nextCE32FromContraction(
+ const CollationData *d, uint32_t contractionCE32,
+ const UChar *p, uint32_t ce32, UChar32 c,
+ UErrorCode &errorCode);
+
+ uint32_t nextCE32FromDiscontiguousContraction(
+ const CollationData *d, UCharsTrie &suffixes, uint32_t ce32,
+ int32_t lookAhead, UChar32 c,
+ UErrorCode &errorCode);
+
+ /**
+ * Returns the previous CE when data->isUnsafeBackward(c, isNumeric).
+ */
+ int64_t previousCEUnsafe(UChar32 c, UVector32 &offsets, UErrorCode &errorCode);
+
+ /**
+ * Turns a string of digits (bytes 0..9)
+ * into a sequence of CEs that will sort in numeric order.
+ *
+ * Starts from this ce32's digit value and consumes the following/preceding digits.
+ * The digits string must not be empty and must not have leading zeros.
+ */
+ void appendNumericCEs(uint32_t ce32, UBool forward, UErrorCode &errorCode);
+
+ /**
+ * Turns 1..254 digits into a sequence of CEs.
+ * Called by appendNumericCEs() for each segment of at most 254 digits.
+ */
+ void appendNumericSegmentCEs(const char *digits, int32_t length, UErrorCode &errorCode);
+
+ CEBuffer ceBuffer;
+ int32_t cesIndex;
+
+ SkippedState *skipped;
+
+ // Number of code points to read forward, or -1.
+ // Used as a forward iteration limit in previousCEUnsafe().
+ int32_t numCpFwd;
+ // Numeric collation (CollationSettings::NUMERIC).
+ UBool isNumeric;
+};
+
+U_NAMESPACE_END
+
+#endif // !UCONFIG_NO_COLLATION
+#endif // __COLLATIONITERATOR_H__