1// © 2016 and later: Unicode, Inc. and others.
2// License & terms of use: http://www.unicode.org/copyright.html
3/*
4*******************************************************************************
5*   Copyright (C) 2010-2016, International Business Machines
6*   Corporation and others.  All Rights Reserved.
7*******************************************************************************
8*   file name:  bytestriebuilder.h
9*   encoding:   UTF-8
10*   tab size:   8 (not used)
11*   indentation:4
12*
13*   created on: 2010sep25
14*   created by: Markus W. Scherer
15*/
16
17/**
18 * \file
19 * \brief C++ API: Builder for icu::BytesTrie
20 */
21
22#ifndef __BYTESTRIEBUILDER_H__
23#define __BYTESTRIEBUILDER_H__
24
25#include "unicode/utypes.h"
26
27#if U_SHOW_CPLUSPLUS_API
28
29#include "unicode/bytestrie.h"
30#include "unicode/stringpiece.h"
31#include "unicode/stringtriebuilder.h"
32
33class BytesTrieTest;
34
35U_NAMESPACE_BEGIN
36
37class BytesTrieElement;
38class CharString;
39/**
40 * Builder class for BytesTrie.
41 *
42 * This class is not intended for public subclassing.
43 * @stable ICU 4.8
44 */
45class U_COMMON_API BytesTrieBuilder : public StringTrieBuilder {
46public:
47    /**
48     * Constructs an empty builder.
49     * @param errorCode Standard ICU error code.
50     * @stable ICU 4.8
51     */
52    BytesTrieBuilder(UErrorCode &errorCode);
53
54    /**
55     * Destructor.
56     * @stable ICU 4.8
57     */
58    virtual ~BytesTrieBuilder();
59
60    /**
61     * Adds a (byte sequence, value) pair.
62     * The byte sequence must be unique.
63     * The bytes will be copied; the builder does not keep
64     * a reference to the input StringPiece or its data().
65     * @param s The input byte sequence.
66     * @param value The value associated with this byte sequence.
67     * @param errorCode Standard ICU error code. Its input value must
68     *                  pass the U_SUCCESS() test, or else the function returns
69     *                  immediately. Check for U_FAILURE() on output or use with
70     *                  function chaining. (See User Guide for details.)
71     * @return *this
72     * @stable ICU 4.8
73     */
74    BytesTrieBuilder &add(StringPiece s, int32_t value, UErrorCode &errorCode);
75
76    /**
77     * Builds a BytesTrie for the add()ed data.
78     * Once built, no further data can be add()ed until clear() is called.
79     *
80     * A BytesTrie cannot be empty. At least one (byte sequence, value) pair
81     * must have been add()ed.
82     *
83     * This method passes ownership of the builder's internal result array to the new trie object.
84     * Another call to any build() variant will re-serialize the trie.
85     * After clear() has been called, a new array will be used as well.
86     * @param buildOption Build option, see UStringTrieBuildOption.
87     * @param errorCode Standard ICU error code. Its input value must
88     *                  pass the U_SUCCESS() test, or else the function returns
89     *                  immediately. Check for U_FAILURE() on output or use with
90     *                  function chaining. (See User Guide for details.)
91     * @return A new BytesTrie for the add()ed data.
92     * @stable ICU 4.8
93     */
94    BytesTrie *build(UStringTrieBuildOption buildOption, UErrorCode &errorCode);
95
96    /**
97     * Builds a BytesTrie for the add()ed data and byte-serializes it.
98     * Once built, no further data can be add()ed until clear() is called.
99     *
100     * A BytesTrie cannot be empty. At least one (byte sequence, value) pair
101     * must have been add()ed.
102     *
103     * Multiple calls to buildStringPiece() return StringPieces referring to the
104     * builder's same byte array, without rebuilding.
105     * If buildStringPiece() is called after build(), the trie will be
106     * re-serialized into a new array (because build() passes on ownership).
107     * If build() is called after buildStringPiece(), the trie object returned
108     * by build() will become the owner of the underlying string for the
109     * previously returned StringPiece.
110     * After clear() has been called, a new array will be used as well.
111     * @param buildOption Build option, see UStringTrieBuildOption.
112     * @param errorCode Standard ICU error code. Its input value must
113     *                  pass the U_SUCCESS() test, or else the function returns
114     *                  immediately. Check for U_FAILURE() on output or use with
115     *                  function chaining. (See User Guide for details.)
116     * @return A StringPiece which refers to the byte-serialized BytesTrie for the add()ed data.
117     * @stable ICU 4.8
118     */
119    StringPiece buildStringPiece(UStringTrieBuildOption buildOption, UErrorCode &errorCode);
120
121    /**
122     * Removes all (byte sequence, value) pairs.
123     * New data can then be add()ed and a new trie can be built.
124     * @return *this
125     * @stable ICU 4.8
126     */
127    BytesTrieBuilder &clear();
128
129private:
130    friend class ::BytesTrieTest;
131
132    BytesTrieBuilder(const BytesTrieBuilder &other) = delete;  // no copy constructor
133    BytesTrieBuilder &operator=(const BytesTrieBuilder &other) = delete;  // no assignment operator
134
135    void buildBytes(UStringTrieBuildOption buildOption, UErrorCode &errorCode);
136
137    virtual int32_t getElementStringLength(int32_t i) const override;
138    virtual char16_t getElementUnit(int32_t i, int32_t byteIndex) const override;
139    virtual int32_t getElementValue(int32_t i) const override;
140
141    virtual int32_t getLimitOfLinearMatch(int32_t first, int32_t last, int32_t byteIndex) const override;
142
143    virtual int32_t countElementUnits(int32_t start, int32_t limit, int32_t byteIndex) const override;
144    virtual int32_t skipElementsBySomeUnits(int32_t i, int32_t byteIndex, int32_t count) const override;
145    virtual int32_t indexOfElementWithNextUnit(int32_t i, int32_t byteIndex, char16_t byte) const override;
146
147    virtual UBool matchNodesCanHaveValues() const override { return false; }
148
149    virtual int32_t getMaxBranchLinearSubNodeLength() const override { return BytesTrie::kMaxBranchLinearSubNodeLength; }
150    virtual int32_t getMinLinearMatch() const override { return BytesTrie::kMinLinearMatch; }
151    virtual int32_t getMaxLinearMatchLength() const override { return BytesTrie::kMaxLinearMatchLength; }
152
153    /**
154     * @internal (private)
155     */
156    class BTLinearMatchNode : public LinearMatchNode {
157    public:
158        BTLinearMatchNode(const char *units, int32_t len, Node *nextNode);
159        virtual bool operator==(const Node &other) const override;
160        virtual void write(StringTrieBuilder &builder) override;
161    private:
162        const char *s;
163    };
164
165    virtual Node *createLinearMatchNode(int32_t i, int32_t byteIndex, int32_t length,
166                                        Node *nextNode) const override;
167
168    UBool ensureCapacity(int32_t length);
169    virtual int32_t write(int32_t byte) override;
170    int32_t write(const char *b, int32_t length);
171    virtual int32_t writeElementUnits(int32_t i, int32_t byteIndex, int32_t length) override;
172    virtual int32_t writeValueAndFinal(int32_t i, UBool isFinal) override;
173    virtual int32_t writeValueAndType(UBool hasValue, int32_t value, int32_t node) override;
174    virtual int32_t writeDeltaTo(int32_t jumpTarget) override;
175    static int32_t internalEncodeDelta(int32_t i, char intBytes[]);
176
177    CharString *strings;  // Pointer not object so we need not #include internal charstr.h.
178    BytesTrieElement *elements;
179    int32_t elementsCapacity;
180    int32_t elementsLength;
181
182    // Byte serialization of the trie.
183    // Grows from the back: bytesLength measures from the end of the buffer!
184    char *bytes;
185    int32_t bytesCapacity;
186    int32_t bytesLength;
187};
188
189U_NAMESPACE_END
190
191#endif /* U_SHOW_CPLUSPLUS_API */
192
193#endif  // __BYTESTRIEBUILDER_H__
194