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 
33 U_NAMESPACE_BEGIN
34 
35 class BytesTrieElement;
36 class CharString;
37 /**
38  * Builder class for BytesTrie.
39  *
40  * This class is not intended for public subclassing.
41  * @stable ICU 4.8
42  */
43 class U_COMMON_API BytesTrieBuilder : public StringTrieBuilder {
44 public:
45     /**
46      * Constructs an empty builder.
47      * @param errorCode Standard ICU error code.
48      * @stable ICU 4.8
49      */
50     BytesTrieBuilder(UErrorCode &errorCode);
51 
52     /**
53      * Destructor.
54      * @stable ICU 4.8
55      */
56     virtual ~BytesTrieBuilder();
57 
58     /**
59      * Adds a (byte sequence, value) pair.
60      * The byte sequence must be unique.
61      * The bytes will be copied; the builder does not keep
62      * a reference to the input StringPiece or its data().
63      * @param s The input byte sequence.
64      * @param value The value associated with this byte sequence.
65      * @param errorCode Standard ICU error code. Its input value must
66      *                  pass the U_SUCCESS() test, or else the function returns
67      *                  immediately. Check for U_FAILURE() on output or use with
68      *                  function chaining. (See User Guide for details.)
69      * @return *this
70      * @stable ICU 4.8
71      */
72     BytesTrieBuilder &add(StringPiece s, int32_t value, UErrorCode &errorCode);
73 
74     /**
75      * Builds a BytesTrie for the add()ed data.
76      * Once built, no further data can be add()ed until clear() is called.
77      *
78      * A BytesTrie cannot be empty. At least one (byte sequence, value) pair
79      * must have been add()ed.
80      *
81      * This method passes ownership of the builder's internal result array to the new trie object.
82      * Another call to any build() variant will re-serialize the trie.
83      * After clear() has been called, a new array will be used as well.
84      * @param buildOption Build option, see UStringTrieBuildOption.
85      * @param errorCode Standard ICU error code. Its input value must
86      *                  pass the U_SUCCESS() test, or else the function returns
87      *                  immediately. Check for U_FAILURE() on output or use with
88      *                  function chaining. (See User Guide for details.)
89      * @return A new BytesTrie for the add()ed data.
90      * @stable ICU 4.8
91      */
92     BytesTrie *build(UStringTrieBuildOption buildOption, UErrorCode &errorCode);
93 
94     /**
95      * Builds a BytesTrie for the add()ed data and byte-serializes it.
96      * Once built, no further data can be add()ed until clear() is called.
97      *
98      * A BytesTrie cannot be empty. At least one (byte sequence, value) pair
99      * must have been add()ed.
100      *
101      * Multiple calls to buildStringPiece() return StringPieces referring to the
102      * builder's same byte array, without rebuilding.
103      * If buildStringPiece() is called after build(), the trie will be
104      * re-serialized into a new array.
105      * If build() is called after buildStringPiece(), the trie object will become
106      * the owner of the previously returned array.
107      * After clear() has been called, a new array will be used as well.
108      * @param buildOption Build option, see UStringTrieBuildOption.
109      * @param errorCode Standard ICU error code. Its input value must
110      *                  pass the U_SUCCESS() test, or else the function returns
111      *                  immediately. Check for U_FAILURE() on output or use with
112      *                  function chaining. (See User Guide for details.)
113      * @return A StringPiece which refers to the byte-serialized BytesTrie for the add()ed data.
114      * @stable ICU 4.8
115      */
116     StringPiece buildStringPiece(UStringTrieBuildOption buildOption, UErrorCode &errorCode);
117 
118     /**
119      * Removes all (byte sequence, value) pairs.
120      * New data can then be add()ed and a new trie can be built.
121      * @return *this
122      * @stable ICU 4.8
123      */
124     BytesTrieBuilder &clear();
125 
126 private:
127     BytesTrieBuilder(const BytesTrieBuilder &other);  // no copy constructor
128     BytesTrieBuilder &operator=(const BytesTrieBuilder &other);  // no assignment operator
129 
130     void buildBytes(UStringTrieBuildOption buildOption, UErrorCode &errorCode);
131 
132     virtual int32_t getElementStringLength(int32_t i) const;
133     virtual char16_t getElementUnit(int32_t i, int32_t byteIndex) const;
134     virtual int32_t getElementValue(int32_t i) const;
135 
136     virtual int32_t getLimitOfLinearMatch(int32_t first, int32_t last, int32_t byteIndex) const;
137 
138     virtual int32_t countElementUnits(int32_t start, int32_t limit, int32_t byteIndex) const;
139     virtual int32_t skipElementsBySomeUnits(int32_t i, int32_t byteIndex, int32_t count) const;
140     virtual int32_t indexOfElementWithNextUnit(int32_t i, int32_t byteIndex, char16_t byte) const;
141 
matchNodesCanHaveValues()142     virtual UBool matchNodesCanHaveValues() const { return FALSE; }
143 
getMaxBranchLinearSubNodeLength()144     virtual int32_t getMaxBranchLinearSubNodeLength() const { return BytesTrie::kMaxBranchLinearSubNodeLength; }
getMinLinearMatch()145     virtual int32_t getMinLinearMatch() const { return BytesTrie::kMinLinearMatch; }
getMaxLinearMatchLength()146     virtual int32_t getMaxLinearMatchLength() const { return BytesTrie::kMaxLinearMatchLength; }
147 
148     /**
149      * @internal (private)
150      */
151     class BTLinearMatchNode : public LinearMatchNode {
152     public:
153         BTLinearMatchNode(const char *units, int32_t len, Node *nextNode);
154         virtual UBool operator==(const Node &other) const;
155         virtual void write(StringTrieBuilder &builder);
156     private:
157         const char *s;
158     };
159 
160     virtual Node *createLinearMatchNode(int32_t i, int32_t byteIndex, int32_t length,
161                                         Node *nextNode) const;
162 
163     UBool ensureCapacity(int32_t length);
164     virtual int32_t write(int32_t byte);
165     int32_t write(const char *b, int32_t length);
166     virtual int32_t writeElementUnits(int32_t i, int32_t byteIndex, int32_t length);
167     virtual int32_t writeValueAndFinal(int32_t i, UBool isFinal);
168     virtual int32_t writeValueAndType(UBool hasValue, int32_t value, int32_t node);
169     virtual int32_t writeDeltaTo(int32_t jumpTarget);
170 
171     CharString *strings;  // Pointer not object so we need not #include internal charstr.h.
172     BytesTrieElement *elements;
173     int32_t elementsCapacity;
174     int32_t elementsLength;
175 
176     // Byte serialization of the trie.
177     // Grows from the back: bytesLength measures from the end of the buffer!
178     char *bytes;
179     int32_t bytesCapacity;
180     int32_t bytesLength;
181 };
182 
183 U_NAMESPACE_END
184 
185 #endif /* U_SHOW_CPLUSPLUS_API */
186 
187 #endif  // __BYTESTRIEBUILDER_H__
188