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