The Tor Browser: comparison intl/icu/source/common/unicode/ucharstrie.h

--1:000000000000
+:506dbf9ebce8
+/*
+*******************************************************************************
+*   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__

The Tor Browser / file comparison

comparison: intl/icu/source/common/unicode/ucharstrie.h

intl/icu/source/common/unicode/ucharstrie.h