initial commit, 4.5 stable

thirdparty/icu4c/common/unicode/stringtriebuilder.h

@@ -0,0 +1,426 @@
+// © 2016 and later: Unicode, Inc. and others.
+// License & terms of use: http://www.unicode.org/copyright.html
+/*
+*******************************************************************************
+*   Copyright (C) 2010-2012,2014, International Business Machines
+*   Corporation and others.  All Rights Reserved.
+*******************************************************************************
+*   file name:  stringtriebuilder.h
+*   encoding:   UTF-8
+*   tab size:   8 (not used)
+*   indentation:4
+*
+*   created on: 2010dec24
+*   created by: Markus W. Scherer
+*/
+
+#ifndef __STRINGTRIEBUILDER_H__
+#define __STRINGTRIEBUILDER_H__
+
+#include "unicode/utypes.h"
+
+#if U_SHOW_CPLUSPLUS_API
+
+#include "unicode/uobject.h"
+
+/**
+ * \file
+ * \brief C++ API: Builder API for trie builders
+ */
+
+// Forward declaration.
+/// \cond
+struct UHashtable;
+typedef struct UHashtable UHashtable;
+/// \endcond
+
+/**
+ * Build options for BytesTrieBuilder and CharsTrieBuilder.
+ * @stable ICU 4.8
+ */
+enum UStringTrieBuildOption {
+    /**
+     * Builds a trie quickly.
+     * @stable ICU 4.8
+     */
+    USTRINGTRIE_BUILD_FAST,
+    /**
+     * Builds a trie more slowly, attempting to generate
+     * a shorter but equivalent serialization.
+     * This build option also uses more memory.
+     *
+     * This option can be effective when many integer values are the same
+     * and string/byte sequence suffixes can be shared.
+     * Runtime speed is not expected to improve.
+     * @stable ICU 4.8
+     */
+    USTRINGTRIE_BUILD_SMALL
+};
+
+U_NAMESPACE_BEGIN
+
+/**
+ * Base class for string trie builder classes.
+ *
+ * This class is not intended for public subclassing.
+ * @stable ICU 4.8
+ */
+class U_COMMON_API StringTrieBuilder : public UObject {
+public:
+#ifndef U_HIDE_INTERNAL_API
+    /** @internal */
+    static int32_t hashNode(const void *node);
+    /** @internal */
+    static UBool equalNodes(const void *left, const void *right);
+#endif  /* U_HIDE_INTERNAL_API */
+
+protected:
+    // Do not enclose the protected default constructor with #ifndef U_HIDE_INTERNAL_API
+    // or else the compiler will create a public default constructor.
+    /** @internal */
+    StringTrieBuilder();
+    /** @internal */
+    virtual ~StringTrieBuilder();
+
+#ifndef U_HIDE_INTERNAL_API
+    /** @internal */
+    void createCompactBuilder(int32_t sizeGuess, UErrorCode &errorCode);
+    /** @internal */
+    void deleteCompactBuilder();
+
+    /** @internal */
+    void build(UStringTrieBuildOption buildOption, int32_t elementsLength, UErrorCode &errorCode);
+
+    /** @internal */
+    int32_t writeNode(int32_t start, int32_t limit, int32_t unitIndex);
+    /** @internal */
+    int32_t writeBranchSubNode(int32_t start, int32_t limit, int32_t unitIndex, int32_t length);
+#endif  /* U_HIDE_INTERNAL_API */
+
+    class Node;
+
+#ifndef U_HIDE_INTERNAL_API
+    /** @internal */
+    Node *makeNode(int32_t start, int32_t limit, int32_t unitIndex, UErrorCode &errorCode);
+    /** @internal */
+    Node *makeBranchSubNode(int32_t start, int32_t limit, int32_t unitIndex,
+                            int32_t length, UErrorCode &errorCode);
+#endif  /* U_HIDE_INTERNAL_API */
+
+    /** @internal */
+    virtual int32_t getElementStringLength(int32_t i) const = 0;
+    /** @internal */
+    virtual char16_t getElementUnit(int32_t i, int32_t unitIndex) const = 0;
+    /** @internal */
+    virtual int32_t getElementValue(int32_t i) const = 0;
+
+    // Finds the first unit index after this one where
+    // the first and last element have different units again.
+    /** @internal */
+    virtual int32_t getLimitOfLinearMatch(int32_t first, int32_t last, int32_t unitIndex) const = 0;
+
+    // Number of different units at unitIndex.
+    /** @internal */
+    virtual int32_t countElementUnits(int32_t start, int32_t limit, int32_t unitIndex) const = 0;
+    /** @internal */
+    virtual int32_t skipElementsBySomeUnits(int32_t i, int32_t unitIndex, int32_t count) const = 0;
+    /** @internal */
+    virtual int32_t indexOfElementWithNextUnit(int32_t i, int32_t unitIndex, char16_t unit) const = 0;
+
+    /** @internal */
+    virtual UBool matchNodesCanHaveValues() const = 0;
+
+    /** @internal */
+    virtual int32_t getMaxBranchLinearSubNodeLength() const = 0;
+    /** @internal */
+    virtual int32_t getMinLinearMatch() const = 0;
+    /** @internal */
+    virtual int32_t getMaxLinearMatchLength() const = 0;
+
+#ifndef U_HIDE_INTERNAL_API
+    // max(BytesTrie::kMaxBranchLinearSubNodeLength, UCharsTrie::kMaxBranchLinearSubNodeLength).
+    /** @internal */
+    static const int32_t kMaxBranchLinearSubNodeLength=5;
+
+    // Maximum number of nested split-branch levels for a branch on all 2^16 possible char16_t units.
+    // log2(2^16/kMaxBranchLinearSubNodeLength) rounded up.
+    /** @internal */
+    static const int32_t kMaxSplitBranchLevels=14;
+
+    /**
+     * Makes sure that there is only one unique node registered that is
+     * equivalent to newNode.
+     * @param newNode Input node. The builder takes ownership.
+     * @param errorCode ICU in/out UErrorCode.
+                        Set to U_MEMORY_ALLOCATION_ERROR if it was success but newNode==nullptr.
+     * @return newNode if it is the first of its kind, or
+     *         an equivalent node if newNode is a duplicate.
+     * @internal
+     */
+    Node *registerNode(Node *newNode, UErrorCode &errorCode);
+    /**
+     * Makes sure that there is only one unique FinalValueNode registered
+     * with this value.
+     * Avoids creating a node if the value is a duplicate.
+     * @param value A final value.
+     * @param errorCode ICU in/out UErrorCode.
+                        Set to U_MEMORY_ALLOCATION_ERROR if it was success but newNode==nullptr.
+     * @return A FinalValueNode with the given value.
+     * @internal
+     */
+    Node *registerFinalValue(int32_t value, UErrorCode &errorCode);
+#endif  /* U_HIDE_INTERNAL_API */
+
+    /*
+     * C++ note:
+     * registerNode() and registerFinalValue() take ownership of their input nodes,
+     * and only return owned nodes.
+     * If they see a failure UErrorCode, they will delete the input node.
+     * If they get a nullptr pointer, they will record a U_MEMORY_ALLOCATION_ERROR.
+     * If there is a failure, they return nullptr.
+     *
+     * nullptr Node pointers can be safely passed into other Nodes because
+     * they call the static Node::hashCode() which checks for a nullptr pointer first.
+     *
+     * Therefore, as long as builder functions register a new node,
+     * they need to check for failures only before explicitly dereferencing
+     * a Node pointer, or before setting a new UErrorCode.
+     */
+
+    // Hash set of nodes, maps from nodes to integer 1.
+    /** @internal */
+    UHashtable *nodes;
+
+    // Do not conditionalize the following with #ifndef U_HIDE_INTERNAL_API,
+    // it is needed for layout of other objects.
+    /**
+     * @internal
+     * \cond
+     */
+    class Node : public UObject {
+    public:
+        Node(int32_t initialHash) : hash(initialHash), offset(0) {}
+        inline int32_t hashCode() const { return hash; }
+        // Handles node==nullptr.
+        static inline int32_t hashCode(const Node *node) { return node==nullptr ? 0 : node->hashCode(); }
+        // Base class operator==() compares the actual class types.
+        virtual bool operator==(const Node &other) const;
+        inline bool operator!=(const Node &other) const { return !operator==(other); }
+        /**
+         * Traverses the Node graph and numbers branch edges, with rightmost edges first.
+         * This is to avoid writing a duplicate node twice.
+         *
+         * Branch nodes in this trie data structure are not symmetric.
+         * Most branch edges "jump" to other nodes but the rightmost branch edges
+         * just continue without a jump.
+         * Therefore, write() must write the rightmost branch edge last
+         * (trie units are written backwards), and must write it at that point even if
+         * it is a duplicate of a node previously written elsewhere.
+         *
+         * This function visits and marks right branch edges first.
+         * Edges are numbered with increasingly negative values because we share the
+         * offset field which gets positive values when nodes are written.
+         * A branch edge also remembers the first number for any of its edges.
+         *
+         * When a further-left branch edge has a number in the range of the rightmost
+         * edge's numbers, then it will be written as part of the required right edge
+         * and we can avoid writing it first.
+         *
+         * After root.markRightEdgesFirst(-1) the offsets of all nodes are negative
+         * edge numbers.
+         *
+         * @param edgeNumber The first edge number for this node and its sub-nodes.
+         * @return An edge number that is at least the maximum-negative
+         *         of the input edge number and the numbers of this node and all of its sub-nodes.
+         */
+        virtual int32_t markRightEdgesFirst(int32_t edgeNumber);
+        // write() must set the offset to a positive value.
+        virtual void write(StringTrieBuilder &builder) = 0;
+        // See markRightEdgesFirst.
+        inline void writeUnlessInsideRightEdge(int32_t firstRight, int32_t lastRight,
+                                               StringTrieBuilder &builder) {
+            // Note: Edge numbers are negative, lastRight<=firstRight.
+            // If offset>0 then this node and its sub-nodes have been written already
+            // and we need not write them again.
+            // If this node is part of the unwritten right branch edge,
+            // then we wait until that is written.
+            if(offset<0 && (offset<lastRight || firstRight<offset)) {
+                write(builder);
+            }
+        }
+        inline int32_t getOffset() const { return offset; }
+    protected:
+        int32_t hash;
+        int32_t offset;
+    };
+
+#ifndef U_HIDE_INTERNAL_API
+    // This class should not be overridden because
+    // registerFinalValue() compares a stack-allocated FinalValueNode
+    // (stack-allocated so that we don't unnecessarily create lots of duplicate nodes)
+    // with the input node, and the
+    // !Node::operator==(other) used inside FinalValueNode::operator==(other)
+    // will be false if the typeid's are different.
+    /** @internal */
+    class FinalValueNode : public Node {
+    public:
+        FinalValueNode(int32_t v) : Node(0x111111u*37u+v), value(v) {}
+        virtual bool operator==(const Node &other) const override;
+        virtual void write(StringTrieBuilder &builder) override;
+    protected:
+        int32_t value;
+    };
+#endif  /* U_HIDE_INTERNAL_API */
+
+    // Do not conditionalize the following with #ifndef U_HIDE_INTERNAL_API,
+    // it is needed for layout of other objects.
+    /**
+     * @internal 
+     */
+    class ValueNode : public Node {
+    public:
+        ValueNode(int32_t initialHash) : Node(initialHash), hasValue(false), value(0) {}
+        virtual bool operator==(const Node &other) const override;
+        void setValue(int32_t v) {
+            hasValue=true;
+            value=v;
+            hash=hash*37u+v;
+        }
+    protected:
+        UBool hasValue;
+        int32_t value;
+    };
+
+#ifndef U_HIDE_INTERNAL_API
+    /** 
+     * @internal 
+     */
+    class IntermediateValueNode : public ValueNode {
+    public:
+        IntermediateValueNode(int32_t v, Node *nextNode)
+                : ValueNode(0x222222u*37u+hashCode(nextNode)), next(nextNode) { setValue(v); }
+        virtual bool operator==(const Node &other) const override;
+        virtual int32_t markRightEdgesFirst(int32_t edgeNumber) override;
+        virtual void write(StringTrieBuilder &builder) override;
+    protected:
+        Node *next;
+    };
+#endif  /* U_HIDE_INTERNAL_API */
+
+    // Do not conditionalize the following with #ifndef U_HIDE_INTERNAL_API,
+    // it is needed for layout of other objects.
+    /**
+     * @internal 
+     */
+    class LinearMatchNode : public ValueNode {
+    public:
+        LinearMatchNode(int32_t len, Node *nextNode)
+                : ValueNode((0x333333u*37u+len)*37u+hashCode(nextNode)),
+                  length(len), next(nextNode) {}
+        virtual bool operator==(const Node &other) const override;
+        virtual int32_t markRightEdgesFirst(int32_t edgeNumber) override;
+    protected:
+        int32_t length;
+        Node *next;
+    };
+
+#ifndef U_HIDE_INTERNAL_API
+    /**
+     * @internal 
+     */
+    class BranchNode : public Node {
+    public:
+        BranchNode(int32_t initialHash) : Node(initialHash) {}
+    protected:
+        int32_t firstEdgeNumber;
+    };
+
+    /**
+     * @internal 
+     */
+    class ListBranchNode : public BranchNode {
+    public:
+        ListBranchNode() : BranchNode(0x444444), length(0) {}
+        virtual bool operator==(const Node &other) const override;
+        virtual int32_t markRightEdgesFirst(int32_t edgeNumber) override;
+        virtual void write(StringTrieBuilder &builder) override;
+        // Adds a unit with a final value.
+        void add(int32_t c, int32_t value) {
+            units[length] = static_cast<char16_t>(c);
+            equal[length]=nullptr;
+            values[length]=value;
+            ++length;
+            hash=(hash*37u+c)*37u+value;
+        }
+        // Adds a unit which leads to another match node.
+        void add(int32_t c, Node *node) {
+            units[length] = static_cast<char16_t>(c);
+            equal[length]=node;
+            values[length]=0;
+            ++length;
+            hash=(hash*37u+c)*37u+hashCode(node);
+        }
+    protected:
+        Node *equal[kMaxBranchLinearSubNodeLength];  // nullptr means "has final value".
+        int32_t length;
+        int32_t values[kMaxBranchLinearSubNodeLength];
+        char16_t units[kMaxBranchLinearSubNodeLength];
+    };
+
+    /**
+     * @internal 
+     */
+    class SplitBranchNode : public BranchNode {
+    public:
+        SplitBranchNode(char16_t middleUnit, Node *lessThanNode, Node *greaterOrEqualNode)
+                : BranchNode(((0x555555u*37u+middleUnit)*37u+
+                              hashCode(lessThanNode))*37u+hashCode(greaterOrEqualNode)),
+                  unit(middleUnit), lessThan(lessThanNode), greaterOrEqual(greaterOrEqualNode) {}
+        virtual bool operator==(const Node &other) const override;
+        virtual int32_t markRightEdgesFirst(int32_t edgeNumber) override;
+        virtual void write(StringTrieBuilder &builder) override;
+    protected:
+        char16_t unit;
+        Node *lessThan;
+        Node *greaterOrEqual;
+    };
+
+    // Branch head node, for writing the actual node lead unit.
+    /** @internal */
+    class BranchHeadNode : public ValueNode {
+    public:
+        BranchHeadNode(int32_t len, Node *subNode)
+                : ValueNode((0x666666u*37u+len)*37u+hashCode(subNode)),
+                  length(len), next(subNode) {}
+        virtual bool operator==(const Node &other) const override;
+        virtual int32_t markRightEdgesFirst(int32_t edgeNumber) override;
+        virtual void write(StringTrieBuilder &builder) override;
+    protected:
+        int32_t length;
+        Node *next;  // A branch sub-node.
+    };
+
+#endif  /* U_HIDE_INTERNAL_API */
+    /// \endcond
+
+    /** @internal */
+    virtual Node *createLinearMatchNode(int32_t i, int32_t unitIndex, int32_t length,
+                                        Node *nextNode) const = 0;
+
+    /** @internal */
+    virtual int32_t write(int32_t unit) = 0;
+    /** @internal */
+    virtual int32_t writeElementUnits(int32_t i, int32_t unitIndex, int32_t length) = 0;
+    /** @internal */
+    virtual int32_t writeValueAndFinal(int32_t i, UBool isFinal) = 0;
+    /** @internal */
+    virtual int32_t writeValueAndType(UBool hasValue, int32_t value, int32_t node) = 0;
+    /** @internal */
+    virtual int32_t writeDeltaTo(int32_t jumpTarget) = 0;
+};
+
+U_NAMESPACE_END
+
+#endif /* U_SHOW_CPLUSPLUS_API */
+
+#endif  // __STRINGTRIEBUILDER_H__