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Diffstat (limited to 'intl/icu/source/common/unicode/ucharstrie.h')
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diff --git a/intl/icu/source/common/unicode/ucharstrie.h b/intl/icu/source/common/unicode/ucharstrie.h new file mode 100644 index 000000000..8daed447c --- /dev/null +++ b/intl/icu/source/common/unicode/ucharstrie.h @@ -0,0 +1,578 @@ +// Copyright (C) 2016 and later: Unicode, Inc. and others. +// License & terms of use: http://www.unicode.org/copyright.html +/* +******************************************************************************* +* Copyright (C) 2010-2012, International Business Machines +* Corporation and others. All Rights Reserved. +******************************************************************************* +* file name: ucharstrie.h +* encoding: US-ASCII +* tab size: 8 (not used) +* indentation:4 +* +* created on: 2010nov14 +* created by: Markus W. Scherer +*/ + +#ifndef __UCHARSTRIE_H__ +#define __UCHARSTRIE_H__ + +/** + * \file + * \brief C++ API: Trie for mapping Unicode strings (or 16-bit-unit sequences) + * to integer values. + */ + +#include "unicode/utypes.h" +#include "unicode/unistr.h" +#include "unicode/uobject.h" +#include "unicode/ustringtrie.h" + +U_NAMESPACE_BEGIN + +class Appendable; +class UCharsTrieBuilder; +class UVector32; + +/** + * Light-weight, non-const reader class for a UCharsTrie. + * Traverses a UChar-serialized data structure with minimal state, + * for mapping strings (16-bit-unit sequences) to non-negative integer values. + * + * This class owns the serialized trie data only if it was constructed by + * the builder's build() method. + * The public constructor and the copy constructor only alias the data (only copy the pointer). + * There is no assignment operator. + * + * This class is not intended for public subclassing. + * @stable ICU 4.8 + */ +class U_COMMON_API UCharsTrie : public UMemory { +public: + /** + * Constructs a UCharsTrie reader instance. + * + * The trieUChars must contain a copy of a UChar sequence from the UCharsTrieBuilder, + * starting with the first UChar of that sequence. + * The UCharsTrie object will not read more UChars than + * the UCharsTrieBuilder generated in the corresponding build() call. + * + * The array is not copied/cloned and must not be modified while + * the UCharsTrie object is in use. + * + * @param trieUChars The UChar array that contains the serialized trie. + * @stable ICU 4.8 + */ + UCharsTrie(const UChar *trieUChars) + : ownedArray_(NULL), uchars_(trieUChars), + pos_(uchars_), remainingMatchLength_(-1) {} + + /** + * Destructor. + * @stable ICU 4.8 + */ + ~UCharsTrie(); + + /** + * Copy constructor, copies the other trie reader object and its state, + * but not the UChar array which will be shared. (Shallow copy.) + * @param other Another UCharsTrie object. + * @stable ICU 4.8 + */ + UCharsTrie(const UCharsTrie &other) + : ownedArray_(NULL), uchars_(other.uchars_), + pos_(other.pos_), remainingMatchLength_(other.remainingMatchLength_) {} + + /** + * Resets this trie to its initial state. + * @return *this + * @stable ICU 4.8 + */ + UCharsTrie &reset() { + pos_=uchars_; + remainingMatchLength_=-1; + return *this; + } + + /** + * UCharsTrie state object, for saving a trie's current state + * and resetting the trie back to this state later. + * @stable ICU 4.8 + */ + class State : public UMemory { + public: + /** + * Constructs an empty State. + * @stable ICU 4.8 + */ + State() { uchars=NULL; } + private: + friend class UCharsTrie; + + const UChar *uchars; + const UChar *pos; + int32_t remainingMatchLength; + }; + + /** + * Saves the state of this trie. + * @param state The State object to hold the trie's state. + * @return *this + * @see resetToState + * @stable ICU 4.8 + */ + const UCharsTrie &saveState(State &state) const { + state.uchars=uchars_; + state.pos=pos_; + state.remainingMatchLength=remainingMatchLength_; + return *this; + } + + /** + * Resets this trie to the saved state. + * If the state object contains no state, or the state of a different trie, + * then this trie remains unchanged. + * @param state The State object which holds a saved trie state. + * @return *this + * @see saveState + * @see reset + * @stable ICU 4.8 + */ + UCharsTrie &resetToState(const State &state) { + if(uchars_==state.uchars && uchars_!=NULL) { + pos_=state.pos; + remainingMatchLength_=state.remainingMatchLength; + } + return *this; + } + + /** + * Determines whether the string so far matches, whether it has a value, + * and whether another input UChar can continue a matching string. + * @return The match/value Result. + * @stable ICU 4.8 + */ + UStringTrieResult current() const; + + /** + * Traverses the trie from the initial state for this input UChar. + * Equivalent to reset().next(uchar). + * @param uchar Input char value. Values below 0 and above 0xffff will never match. + * @return The match/value Result. + * @stable ICU 4.8 + */ + inline UStringTrieResult first(int32_t uchar) { + remainingMatchLength_=-1; + return nextImpl(uchars_, uchar); + } + + /** + * Traverses the trie from the initial state for the + * one or two UTF-16 code units for this input code point. + * Equivalent to reset().nextForCodePoint(cp). + * @param cp A Unicode code point 0..0x10ffff. + * @return The match/value Result. + * @stable ICU 4.8 + */ + UStringTrieResult firstForCodePoint(UChar32 cp); + + /** + * Traverses the trie from the current state for this input UChar. + * @param uchar Input char value. Values below 0 and above 0xffff will never match. + * @return The match/value Result. + * @stable ICU 4.8 + */ + UStringTrieResult next(int32_t uchar); + + /** + * Traverses the trie from the current state for the + * one or two UTF-16 code units for this input code point. + * @param cp A Unicode code point 0..0x10ffff. + * @return The match/value Result. + * @stable ICU 4.8 + */ + UStringTrieResult nextForCodePoint(UChar32 cp); + + /** + * Traverses the trie from the current state for this string. + * Equivalent to + * \code + * Result result=current(); + * for(each c in s) + * if(!USTRINGTRIE_HAS_NEXT(result)) return USTRINGTRIE_NO_MATCH; + * result=next(c); + * return result; + * \endcode + * @param s A string. Can be NULL if length is 0. + * @param length The length of the string. Can be -1 if NUL-terminated. + * @return The match/value Result. + * @stable ICU 4.8 + */ + UStringTrieResult next(const UChar *s, int32_t length); + + /** + * Returns a matching string's value if called immediately after + * current()/first()/next() returned USTRINGTRIE_INTERMEDIATE_VALUE or USTRINGTRIE_FINAL_VALUE. + * getValue() can be called multiple times. + * + * Do not call getValue() after USTRINGTRIE_NO_MATCH or USTRINGTRIE_NO_VALUE! + * @return The value for the string so far. + * @stable ICU 4.8 + */ + inline int32_t getValue() const { + const UChar *pos=pos_; + int32_t leadUnit=*pos++; + // U_ASSERT(leadUnit>=kMinValueLead); + return leadUnit&kValueIsFinal ? + readValue(pos, leadUnit&0x7fff) : readNodeValue(pos, leadUnit); + } + + /** + * Determines whether all strings reachable from the current state + * map to the same value. + * @param uniqueValue Receives the unique value, if this function returns TRUE. + * (output-only) + * @return TRUE if all strings reachable from the current state + * map to the same value. + * @stable ICU 4.8 + */ + inline UBool hasUniqueValue(int32_t &uniqueValue) const { + const UChar *pos=pos_; + // Skip the rest of a pending linear-match node. + return pos!=NULL && findUniqueValue(pos+remainingMatchLength_+1, FALSE, uniqueValue); + } + + /** + * Finds each UChar which continues the string from the current state. + * That is, each UChar c for which it would be next(c)!=USTRINGTRIE_NO_MATCH now. + * @param out Each next UChar is appended to this object. + * @return the number of UChars which continue the string from here + * @stable ICU 4.8 + */ + int32_t getNextUChars(Appendable &out) const; + + /** + * Iterator for all of the (string, value) pairs in a UCharsTrie. + * @stable ICU 4.8 + */ + class U_COMMON_API Iterator : public UMemory { + public: + /** + * Iterates from the root of a UChar-serialized UCharsTrie. + * @param trieUChars The trie UChars. + * @param maxStringLength If 0, the iterator returns full strings. + * Otherwise, the iterator returns strings with this maximum length. + * @param errorCode Standard ICU error code. Its input value must + * pass the U_SUCCESS() test, or else the function returns + * immediately. Check for U_FAILURE() on output or use with + * function chaining. (See User Guide for details.) + * @stable ICU 4.8 + */ + Iterator(const UChar *trieUChars, int32_t maxStringLength, UErrorCode &errorCode); + + /** + * Iterates from the current state of the specified UCharsTrie. + * @param trie The trie whose state will be copied for iteration. + * @param maxStringLength If 0, the iterator returns full strings. + * Otherwise, the iterator returns strings with this maximum length. + * @param errorCode Standard ICU error code. Its input value must + * pass the U_SUCCESS() test, or else the function returns + * immediately. Check for U_FAILURE() on output or use with + * function chaining. (See User Guide for details.) + * @stable ICU 4.8 + */ + Iterator(const UCharsTrie &trie, int32_t maxStringLength, UErrorCode &errorCode); + + /** + * Destructor. + * @stable ICU 4.8 + */ + ~Iterator(); + + /** + * Resets this iterator to its initial state. + * @return *this + * @stable ICU 4.8 + */ + Iterator &reset(); + + /** + * @return TRUE if there are more elements. + * @stable ICU 4.8 + */ + UBool hasNext() const; + + /** + * Finds the next (string, value) pair if there is one. + * + * If the string is truncated to the maximum length and does not + * have a real value, then the value is set to -1. + * In this case, this "not a real value" is indistinguishable from + * a real value of -1. + * @param errorCode Standard ICU error code. Its input value must + * pass the U_SUCCESS() test, or else the function returns + * immediately. Check for U_FAILURE() on output or use with + * function chaining. (See User Guide for details.) + * @return TRUE if there is another element. + * @stable ICU 4.8 + */ + UBool next(UErrorCode &errorCode); + + /** + * @return The string for the last successful next(). + * @stable ICU 4.8 + */ + const UnicodeString &getString() const { return str_; } + /** + * @return The value for the last successful next(). + * @stable ICU 4.8 + */ + int32_t getValue() const { return value_; } + + private: + UBool truncateAndStop() { + pos_=NULL; + value_=-1; // no real value for str + return TRUE; + } + + const UChar *branchNext(const UChar *pos, int32_t length, UErrorCode &errorCode); + + const UChar *uchars_; + const UChar *pos_; + const UChar *initialPos_; + int32_t remainingMatchLength_; + int32_t initialRemainingMatchLength_; + UBool skipValue_; // Skip intermediate value which was already delivered. + + UnicodeString str_; + int32_t maxLength_; + int32_t value_; + + // The stack stores pairs of integers for backtracking to another + // outbound edge of a branch node. + // The first integer is an offset from uchars_. + // The second integer has the str_.length() from before the node in bits 15..0, + // and the remaining branch length in bits 31..16. + // (We could store the remaining branch length minus 1 in bits 30..16 and not use the sign bit, + // but the code looks more confusing that way.) + UVector32 *stack_; + }; + +private: + friend class UCharsTrieBuilder; + + /** + * Constructs a UCharsTrie reader instance. + * Unlike the public constructor which just aliases an array, + * this constructor adopts the builder's array. + * This constructor is only called by the builder. + */ + UCharsTrie(UChar *adoptUChars, const UChar *trieUChars) + : ownedArray_(adoptUChars), uchars_(trieUChars), + pos_(uchars_), remainingMatchLength_(-1) {} + + // No assignment operator. + UCharsTrie &operator=(const UCharsTrie &other); + + inline void stop() { + pos_=NULL; + } + + // Reads a compact 32-bit integer. + // pos is already after the leadUnit, and the lead unit has bit 15 reset. + static inline int32_t readValue(const UChar *pos, int32_t leadUnit) { + int32_t value; + if(leadUnit<kMinTwoUnitValueLead) { + value=leadUnit; + } else if(leadUnit<kThreeUnitValueLead) { + value=((leadUnit-kMinTwoUnitValueLead)<<16)|*pos; + } else { + value=(pos[0]<<16)|pos[1]; + } + return value; + } + static inline const UChar *skipValue(const UChar *pos, int32_t leadUnit) { + if(leadUnit>=kMinTwoUnitValueLead) { + if(leadUnit<kThreeUnitValueLead) { + ++pos; + } else { + pos+=2; + } + } + return pos; + } + static inline const UChar *skipValue(const UChar *pos) { + int32_t leadUnit=*pos++; + return skipValue(pos, leadUnit&0x7fff); + } + + static inline int32_t readNodeValue(const UChar *pos, int32_t leadUnit) { + // U_ASSERT(kMinValueLead<=leadUnit && leadUnit<kValueIsFinal); + int32_t value; + if(leadUnit<kMinTwoUnitNodeValueLead) { + value=(leadUnit>>6)-1; + } else if(leadUnit<kThreeUnitNodeValueLead) { + value=(((leadUnit&0x7fc0)-kMinTwoUnitNodeValueLead)<<10)|*pos; + } else { + value=(pos[0]<<16)|pos[1]; + } + return value; + } + static inline const UChar *skipNodeValue(const UChar *pos, int32_t leadUnit) { + // U_ASSERT(kMinValueLead<=leadUnit && leadUnit<kValueIsFinal); + if(leadUnit>=kMinTwoUnitNodeValueLead) { + if(leadUnit<kThreeUnitNodeValueLead) { + ++pos; + } else { + pos+=2; + } + } + return pos; + } + + static inline const UChar *jumpByDelta(const UChar *pos) { + int32_t delta=*pos++; + if(delta>=kMinTwoUnitDeltaLead) { + if(delta==kThreeUnitDeltaLead) { + delta=(pos[0]<<16)|pos[1]; + pos+=2; + } else { + delta=((delta-kMinTwoUnitDeltaLead)<<16)|*pos++; + } + } + return pos+delta; + } + + static const UChar *skipDelta(const UChar *pos) { + int32_t delta=*pos++; + if(delta>=kMinTwoUnitDeltaLead) { + if(delta==kThreeUnitDeltaLead) { + pos+=2; + } else { + ++pos; + } + } + return pos; + } + + static inline UStringTrieResult valueResult(int32_t node) { + return (UStringTrieResult)(USTRINGTRIE_INTERMEDIATE_VALUE-(node>>15)); + } + + // Handles a branch node for both next(uchar) and next(string). + UStringTrieResult branchNext(const UChar *pos, int32_t length, int32_t uchar); + + // Requires remainingLength_<0. + UStringTrieResult nextImpl(const UChar *pos, int32_t uchar); + + // Helper functions for hasUniqueValue(). + // Recursively finds a unique value (or whether there is not a unique one) + // from a branch. + static const UChar *findUniqueValueFromBranch(const UChar *pos, int32_t length, + UBool haveUniqueValue, int32_t &uniqueValue); + // Recursively finds a unique value (or whether there is not a unique one) + // starting from a position on a node lead unit. + static UBool findUniqueValue(const UChar *pos, UBool haveUniqueValue, int32_t &uniqueValue); + + // Helper functions for getNextUChars(). + // getNextUChars() when pos is on a branch node. + static void getNextBranchUChars(const UChar *pos, int32_t length, Appendable &out); + + // UCharsTrie data structure + // + // The trie consists of a series of UChar-serialized nodes for incremental + // Unicode string/UChar sequence matching. (UChar=16-bit unsigned integer) + // The root node is at the beginning of the trie data. + // + // Types of nodes are distinguished by their node lead unit ranges. + // After each node, except a final-value node, another node follows to + // encode match values or continue matching further units. + // + // Node types: + // - Final-value node: Stores a 32-bit integer in a compact, variable-length format. + // The value is for the string/UChar sequence so far. + // - Match node, optionally with an intermediate value in a different compact format. + // The value, if present, is for the string/UChar sequence so far. + // + // Aside from the value, which uses the node lead unit's high bits: + // + // - Linear-match node: Matches a number of units. + // - Branch node: Branches to other nodes according to the current input unit. + // The node unit is the length of the branch (number of units to select from) + // minus 1. It is followed by a sub-node: + // - If the length is at most kMaxBranchLinearSubNodeLength, then + // there are length-1 (key, value) pairs and then one more comparison unit. + // If one of the key units matches, then the value is either a final value for + // the string so far, or a "jump" delta to the next node. + // If the last unit matches, then matching continues with the next node. + // (Values have the same encoding as final-value nodes.) + // - If the length is greater than kMaxBranchLinearSubNodeLength, then + // there is one unit and one "jump" delta. + // If the input unit is less than the sub-node unit, then "jump" by delta to + // the next sub-node which will have a length of length/2. + // (The delta has its own compact encoding.) + // Otherwise, skip the "jump" delta to the next sub-node + // which will have a length of length-length/2. + + // Match-node lead unit values, after masking off intermediate-value bits: + + // 0000..002f: Branch node. If node!=0 then the length is node+1, otherwise + // the length is one more than the next unit. + + // For a branch sub-node with at most this many entries, we drop down + // to a linear search. + static const int32_t kMaxBranchLinearSubNodeLength=5; + + // 0030..003f: Linear-match node, match 1..16 units and continue reading the next node. + static const int32_t kMinLinearMatch=0x30; + static const int32_t kMaxLinearMatchLength=0x10; + + // Match-node lead unit bits 14..6 for the optional intermediate value. + // If these bits are 0, then there is no intermediate value. + // Otherwise, see the *NodeValue* constants below. + static const int32_t kMinValueLead=kMinLinearMatch+kMaxLinearMatchLength; // 0x0040 + static const int32_t kNodeTypeMask=kMinValueLead-1; // 0x003f + + // A final-value node has bit 15 set. + static const int32_t kValueIsFinal=0x8000; + + // Compact value: After testing and masking off bit 15, use the following thresholds. + static const int32_t kMaxOneUnitValue=0x3fff; + + static const int32_t kMinTwoUnitValueLead=kMaxOneUnitValue+1; // 0x4000 + static const int32_t kThreeUnitValueLead=0x7fff; + + static const int32_t kMaxTwoUnitValue=((kThreeUnitValueLead-kMinTwoUnitValueLead)<<16)-1; // 0x3ffeffff + + // Compact intermediate-value integer, lead unit shared with a branch or linear-match node. + static const int32_t kMaxOneUnitNodeValue=0xff; + static const int32_t kMinTwoUnitNodeValueLead=kMinValueLead+((kMaxOneUnitNodeValue+1)<<6); // 0x4040 + static const int32_t kThreeUnitNodeValueLead=0x7fc0; + + static const int32_t kMaxTwoUnitNodeValue= + ((kThreeUnitNodeValueLead-kMinTwoUnitNodeValueLead)<<10)-1; // 0xfdffff + + // Compact delta integers. + static const int32_t kMaxOneUnitDelta=0xfbff; + static const int32_t kMinTwoUnitDeltaLead=kMaxOneUnitDelta+1; // 0xfc00 + static const int32_t kThreeUnitDeltaLead=0xffff; + + static const int32_t kMaxTwoUnitDelta=((kThreeUnitDeltaLead-kMinTwoUnitDeltaLead)<<16)-1; // 0x03feffff + + UChar *ownedArray_; + + // Fixed value referencing the UCharsTrie words. + const UChar *uchars_; + + // Iterator variables. + + // Pointer to next trie unit to read. NULL if no more matches. + const UChar *pos_; + // Remaining length of a linear-match node, minus 1. Negative if not in such a node. + int32_t remainingMatchLength_; +}; + +U_NAMESPACE_END + +#endif // __UCHARSTRIE_H__ |