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1 // © 2016 and later: Unicode, Inc. and others.
2 // License & terms of use: http://www.unicode.org/copyright.html
3 /*
4 *******************************************************************************
5 * Copyright (C) 2014, International Business Machines
6 * Corporation and others.  All Rights Reserved.
7 *******************************************************************************
8 * dictionarydata.h
9 *
10 * created on: 2012may31
11 * created by: Markus W. Scherer & Maxime Serrano
12 */
13 
14 #ifndef __DICTIONARYDATA_H__
15 #define __DICTIONARYDATA_H__
16 
17 #include "unicode/utypes.h"
18 
19 #if !UCONFIG_NO_BREAK_ITERATION
20 
21 #include "unicode/utext.h"
22 #include "unicode/udata.h"
23 #include "udataswp.h"
24 #include "unicode/uobject.h"
25 #include "unicode/ustringtrie.h"
26 
27 U_NAMESPACE_BEGIN
28 
29 class UCharsTrie;
30 class BytesTrie;
31 
32 class U_COMMON_API DictionaryData : public UMemory {
33 public:
34     static const int32_t TRIE_TYPE_BYTES; // = 0;
35     static const int32_t TRIE_TYPE_UCHARS; // = 1;
36     static const int32_t TRIE_TYPE_MASK; // = 7;
37     static const int32_t TRIE_HAS_VALUES; // = 8;
38 
39     static const int32_t TRANSFORM_NONE; // = 0;
40     static const int32_t TRANSFORM_TYPE_OFFSET; // = 0x1000000;
41     static const int32_t TRANSFORM_TYPE_MASK; // = 0x7f000000;
42     static const int32_t TRANSFORM_OFFSET_MASK; // = 0x1fffff;
43 
44     enum {
45         // Byte offsets from the start of the data, after the generic header.
46         IX_STRING_TRIE_OFFSET,
47         IX_RESERVED1_OFFSET,
48         IX_RESERVED2_OFFSET,
49         IX_TOTAL_SIZE,
50 
51         // Trie type: TRIE_HAS_VALUES | TRIE_TYPE_BYTES etc.
52         IX_TRIE_TYPE,
53         // Transform specification: TRANSFORM_TYPE_OFFSET | 0xe00 etc.
54         IX_TRANSFORM,
55 
56         IX_RESERVED6,
57         IX_RESERVED7,
58         IX_COUNT
59     };
60 };
61 
62 /**
63  * Wrapper class around generic dictionaries, implementing matches().
64  * getType() should return a TRIE_TYPE_??? constant from DictionaryData.
65  *
66  * All implementations of this interface must be thread-safe if they are to be used inside of the
67  * dictionary-based break iteration code.
68  */
69 class U_COMMON_API DictionaryMatcher : public UMemory {
70 public:
DictionaryMatcher()71     DictionaryMatcher() {}
72     virtual ~DictionaryMatcher();
73     // this should emulate CompactTrieDictionary::matches()
74     /*  @param text      The text in which to look for matching words. Matching begins
75      *                   at the current position of the UText.
76      *  @param maxLength The max length of match to consider. Units are the native indexing
77      *                   units of the UText.
78      *  @param limit     Capacity of output arrays, which is also the maximum number of
79      *                   matching words to be found.
80      *  @param lengths   output array, filled with the lengths of the matches, in order,
81      *                   from shortest to longest. Lengths are in native indexing units
82      *                   of the UText. May be NULL.
83      *  @param cpLengths output array, filled with the lengths of the matches, in order,
84      *                   from shortest to longest. Lengths are the number of Unicode code points.
85      *                   May be NULL.
86      *  @param values    Output array, filled with the values associated with the words found.
87      *                   May be NULL.
88      *  @param prefix    Output parameter, the code point length of the prefix match, even if that
89      *                   prefix didn't lead to a complete word. Will always be >= the cpLength
90      *                   of the longest complete word matched. May be NULL.
91      *  @return          Number of matching words found.
92      */
93     virtual int32_t matches(UText *text, int32_t maxLength, int32_t limit,
94                             int32_t *lengths, int32_t *cpLengths, int32_t *values,
95                             int32_t *prefix) const = 0;
96 
97     /** @return DictionaryData::TRIE_TYPE_XYZ */
98     virtual int32_t getType() const = 0;
99 };
100 
101 // Implementation of the DictionaryMatcher interface for a UCharsTrie dictionary
102 class U_COMMON_API UCharsDictionaryMatcher : public DictionaryMatcher {
103 public:
104     // constructs a new UCharsDictionaryMatcher.
105     // The UDataMemory * will be closed on this object's destruction.
UCharsDictionaryMatcher(const UChar * c,UDataMemory * f)106     UCharsDictionaryMatcher(const UChar *c, UDataMemory *f) : characters(c), file(f) { }
107     virtual ~UCharsDictionaryMatcher();
108     virtual int32_t matches(UText *text, int32_t maxLength, int32_t limit,
109                             int32_t *lengths, int32_t *cpLengths, int32_t *values,
110                             int32_t *prefix) const override;
111     virtual int32_t getType() const override;
112 private:
113     const UChar *characters;
114     UDataMemory *file;
115 };
116 
117 // Implementation of the DictionaryMatcher interface for a BytesTrie dictionary
118 class U_COMMON_API BytesDictionaryMatcher : public DictionaryMatcher {
119 public:
120     // constructs a new BytesTrieDictionaryMatcher
121     // the transform constant should be the constant read from the file, not a masked version!
122     // the UDataMemory * fed in here will be closed on this object's destruction
BytesDictionaryMatcher(const char * c,int32_t t,UDataMemory * f)123     BytesDictionaryMatcher(const char *c, int32_t t, UDataMemory *f)
124             : characters(c), transformConstant(t), file(f) { }
125     virtual ~BytesDictionaryMatcher();
126     virtual int32_t matches(UText *text, int32_t maxLength, int32_t limit,
127                             int32_t *lengths, int32_t *cpLengths, int32_t *values,
128                             int32_t *prefix) const override;
129     virtual int32_t getType() const override;
130 private:
131     UChar32 transform(UChar32 c) const;
132 
133     const char *characters;
134     int32_t transformConstant;
135     UDataMemory *file;
136 };
137 
138 U_NAMESPACE_END
139 
140 U_CAPI int32_t U_EXPORT2
141 udict_swap(const UDataSwapper *ds, const void *inData, int32_t length, void *outData, UErrorCode *pErrorCode);
142 
143 /**
144  * Format of dictionary .dict data files.
145  * Format version 1.0.
146  *
147  * A dictionary .dict data file contains a byte-serialized BytesTrie or
148  * a UChars-serialized UCharsTrie.
149  * Such files are used in dictionary-based break iteration (DBBI).
150  *
151  * For a BytesTrie, a transformation type is specified for
152  * transforming Unicode strings into byte sequences.
153  *
154  * A .dict file begins with a standard ICU data file header
155  * (DataHeader, see ucmndata.h and unicode/udata.h).
156  * The UDataInfo.dataVersion field is currently unused (set to 0.0.0.0).
157  *
158  * After the header, the file contains the following parts.
159  * Constants are defined in the DictionaryData class.
160  *
161  * For the data structure of BytesTrie & UCharsTrie see
162  * https://icu.unicode.org/design/struct/tries
163  * and the bytestrie.h and ucharstrie.h header files.
164  *
165  * int32_t indexes[indexesLength]; -- indexesLength=indexes[IX_STRING_TRIE_OFFSET]/4;
166  *
167  *      The first four indexes are byte offsets in ascending order.
168  *      Each byte offset marks the start of the next part in the data file,
169  *      and the end of the previous one.
170  *      When two consecutive byte offsets are the same, then the corresponding part is empty.
171  *      Byte offsets are offsets from after the header,
172  *      that is, from the beginning of the indexes[].
173  *      Each part starts at an offset with proper alignment for its data.
174  *      If necessary, the previous part may include padding bytes to achieve this alignment.
175  *
176  *      trieType=indexes[IX_TRIE_TYPE] defines the trie type.
177  *      transform=indexes[IX_TRANSFORM] defines the Unicode-to-bytes transformation.
178  *          If the transformation type is TRANSFORM_TYPE_OFFSET,
179  *          then the lower 21 bits contain the offset code point.
180  *          Each code point c is mapped to byte b = (c - offset).
181  *          Code points outside the range offset..(offset+0xff) cannot be mapped
182  *          and do not occur in the dictionary.
183  *
184  * stringTrie; -- a serialized BytesTrie or UCharsTrie
185  *
186  *      The dictionary maps strings to specific values (TRIE_HAS_VALUES bit set in trieType),
187  *      or it maps all strings to 0 (TRIE_HAS_VALUES bit not set).
188  */
189 
190 #endif  /* !UCONFIG_NO_BREAK_ITERATION */
191 #endif  /* __DICTIONARYDATA_H__ */
192