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1 // © 2017 and later: Unicode, Inc. and others.
2 // License & terms of use: http://www.unicode.org/copyright.html
3 
4 // umutablecptrie.h (split out of ucptrie.h)
5 // created: 2018jan24 Markus W. Scherer
6 
7 #ifndef __UMUTABLECPTRIE_H__
8 #define __UMUTABLECPTRIE_H__
9 
10 #include "unicode/utypes.h"
11 
12 #include "unicode/ucpmap.h"
13 #include "unicode/ucptrie.h"
14 #include "unicode/utf8.h"
15 
16 #if U_SHOW_CPLUSPLUS_API
17 #include "unicode/localpointer.h"
18 #endif   // U_SHOW_CPLUSPLUS_API
19 
20 U_CDECL_BEGIN
21 
22 /**
23  * \file
24  * \brief C API: This file defines a mutable Unicode code point trie.
25  *
26  * @see UCPTrie
27  * @see UMutableCPTrie
28  */
29 
30 /**
31  * Mutable Unicode code point trie.
32  * Fast map from Unicode code points (U+0000..U+10FFFF) to 32-bit integer values.
33  * For details see https://icu.unicode.org/design/struct/utrie
34  *
35  * Setting values (especially ranges) and lookup is fast.
36  * The mutable trie is only somewhat space-efficient.
37  * It builds a compacted, immutable UCPTrie.
38  *
39  * This trie can be modified while iterating over its contents.
40  * For example, it is possible to merge its values with those from another
41  * set of ranges (e.g., another mutable or immutable trie):
42  * Iterate over those source ranges; for each of them iterate over this trie;
43  * add the source value into the value of each trie range.
44  *
45  * @see UCPTrie
46  * @see umutablecptrie_buildImmutable
47  * @stable ICU 63
48  */
49 typedef struct UMutableCPTrie UMutableCPTrie;
50 
51 /**
52  * Creates a mutable trie that initially maps each Unicode code point to the same value.
53  * It uses 32-bit data values until umutablecptrie_buildImmutable() is called.
54  * umutablecptrie_buildImmutable() takes a valueWidth parameter which
55  * determines the number of bits in the data value in the resulting UCPTrie.
56  * You must umutablecptrie_close() the trie once you are done using it.
57  *
58  * @param initialValue the initial value that is set for all code points
59  * @param errorValue the value for out-of-range code points and ill-formed UTF-8/16
60  * @param pErrorCode an in/out ICU UErrorCode
61  * @return the trie
62  * @stable ICU 63
63  */
64 U_CAPI UMutableCPTrie * U_EXPORT2
65 umutablecptrie_open(uint32_t initialValue, uint32_t errorValue, UErrorCode *pErrorCode);
66 
67 /**
68  * Clones a mutable trie.
69  * You must umutablecptrie_close() the clone once you are done using it.
70  *
71  * @param other the trie to clone
72  * @param pErrorCode an in/out ICU UErrorCode
73  * @return the trie clone
74  * @stable ICU 63
75  */
76 U_CAPI UMutableCPTrie * U_EXPORT2
77 umutablecptrie_clone(const UMutableCPTrie *other, UErrorCode *pErrorCode);
78 
79 /**
80  * Closes a mutable trie and releases associated memory.
81  *
82  * @param trie the trie
83  * @stable ICU 63
84  */
85 U_CAPI void U_EXPORT2
86 umutablecptrie_close(UMutableCPTrie *trie);
87 
88 /**
89  * Creates a mutable trie with the same contents as the UCPMap.
90  * You must umutablecptrie_close() the mutable trie once you are done using it.
91  *
92  * @param map the source map
93  * @param pErrorCode an in/out ICU UErrorCode
94  * @return the mutable trie
95  * @stable ICU 63
96  */
97 U_CAPI UMutableCPTrie * U_EXPORT2
98 umutablecptrie_fromUCPMap(const UCPMap *map, UErrorCode *pErrorCode);
99 
100 /**
101  * Creates a mutable trie with the same contents as the immutable one.
102  * You must umutablecptrie_close() the mutable trie once you are done using it.
103  *
104  * @param trie the immutable trie
105  * @param pErrorCode an in/out ICU UErrorCode
106  * @return the mutable trie
107  * @stable ICU 63
108  */
109 U_CAPI UMutableCPTrie * U_EXPORT2
110 umutablecptrie_fromUCPTrie(const UCPTrie *trie, UErrorCode *pErrorCode);
111 
112 /**
113  * Returns the value for a code point as stored in the trie.
114  *
115  * @param trie the trie
116  * @param c the code point
117  * @return the value
118  * @stable ICU 63
119  */
120 U_CAPI uint32_t U_EXPORT2
121 umutablecptrie_get(const UMutableCPTrie *trie, UChar32 c);
122 
123 /**
124  * Returns the last code point such that all those from start to there have the same value.
125  * Can be used to efficiently iterate over all same-value ranges in a trie.
126  * (This is normally faster than iterating over code points and get()ting each value,
127  * but much slower than a data structure that stores ranges directly.)
128  *
129  * The trie can be modified between calls to this function.
130  *
131  * If the UCPMapValueFilter function pointer is not NULL, then
132  * the value to be delivered is passed through that function, and the return value is the end
133  * of the range where all values are modified to the same actual value.
134  * The value is unchanged if that function pointer is NULL.
135  *
136  * See the same-signature ucptrie_getRange() for a code sample.
137  *
138  * @param trie the trie
139  * @param start range start
140  * @param option defines whether surrogates are treated normally,
141  *               or as having the surrogateValue; usually UCPMAP_RANGE_NORMAL
142  * @param surrogateValue value for surrogates; ignored if option==UCPMAP_RANGE_NORMAL
143  * @param filter a pointer to a function that may modify the trie data value,
144  *     or NULL if the values from the trie are to be used unmodified
145  * @param context an opaque pointer that is passed on to the filter function
146  * @param pValue if not NULL, receives the value that every code point start..end has;
147  *     may have been modified by filter(context, trie value)
148  *     if that function pointer is not NULL
149  * @return the range end code point, or -1 if start is not a valid code point
150  * @stable ICU 63
151  */
152 U_CAPI UChar32 U_EXPORT2
153 umutablecptrie_getRange(const UMutableCPTrie *trie, UChar32 start,
154                         UCPMapRangeOption option, uint32_t surrogateValue,
155                         UCPMapValueFilter *filter, const void *context, uint32_t *pValue);
156 
157 /**
158  * Sets a value for a code point.
159  *
160  * @param trie the trie
161  * @param c the code point
162  * @param value the value
163  * @param pErrorCode an in/out ICU UErrorCode
164  * @stable ICU 63
165  */
166 U_CAPI void U_EXPORT2
167 umutablecptrie_set(UMutableCPTrie *trie, UChar32 c, uint32_t value, UErrorCode *pErrorCode);
168 
169 /**
170  * Sets a value for each code point [start..end].
171  * Faster and more space-efficient than setting the value for each code point separately.
172  *
173  * @param trie the trie
174  * @param start the first code point to get the value
175  * @param end the last code point to get the value (inclusive)
176  * @param value the value
177  * @param pErrorCode an in/out ICU UErrorCode
178  * @stable ICU 63
179  */
180 U_CAPI void U_EXPORT2
181 umutablecptrie_setRange(UMutableCPTrie *trie,
182                         UChar32 start, UChar32 end,
183                         uint32_t value, UErrorCode *pErrorCode);
184 
185 /**
186  * Compacts the data and builds an immutable UCPTrie according to the parameters.
187  * After this, the mutable trie will be empty.
188  *
189  * The mutable trie stores 32-bit values until buildImmutable() is called.
190  * If values shorter than 32 bits are to be stored in the immutable trie,
191  * then the upper bits are discarded.
192  * For example, when the mutable trie contains values 0x81, -0x7f, and 0xa581,
193  * and the value width is 8 bits, then each of these is stored as 0x81
194  * and the immutable trie will return that as an unsigned value.
195  * (Some implementations may want to make productive temporary use of the upper bits
196  * until buildImmutable() discards them.)
197  *
198  * Not every possible set of mappings can be built into a UCPTrie,
199  * because of limitations resulting from speed and space optimizations.
200  * Every Unicode assigned character can be mapped to a unique value.
201  * Typical data yields data structures far smaller than the limitations.
202  *
203  * It is possible to construct extremely unusual mappings that exceed the data structure limits.
204  * In such a case this function will fail with a U_INDEX_OUTOFBOUNDS_ERROR.
205  *
206  * @param trie the trie trie
207  * @param type selects the trie type
208  * @param valueWidth selects the number of bits in a trie data value; if smaller than 32 bits,
209  *                   then the values stored in the trie will be truncated first
210  * @param pErrorCode an in/out ICU UErrorCode
211  *
212  * @see umutablecptrie_fromUCPTrie
213  * @stable ICU 63
214  */
215 U_CAPI UCPTrie * U_EXPORT2
216 umutablecptrie_buildImmutable(UMutableCPTrie *trie, UCPTrieType type, UCPTrieValueWidth valueWidth,
217                               UErrorCode *pErrorCode);
218 
219 U_CDECL_END
220 
221 #if U_SHOW_CPLUSPLUS_API
222 
223 U_NAMESPACE_BEGIN
224 
225 /**
226  * \class LocalUMutableCPTriePointer
227  * "Smart pointer" class, closes a UMutableCPTrie via umutablecptrie_close().
228  * For most methods see the LocalPointerBase base class.
229  *
230  * @see LocalPointerBase
231  * @see LocalPointer
232  * @stable ICU 63
233  */
234 U_DEFINE_LOCAL_OPEN_POINTER(LocalUMutableCPTriePointer, UMutableCPTrie, umutablecptrie_close);
235 
236 U_NAMESPACE_END
237 
238 #endif
239 
240 #endif
241