1 // © 2016 and later: Unicode, Inc. and others.
2 // License & terms of use: http://www.unicode.org/copyright.html
3 /*
4 **********************************************************************
5 * Copyright (c) 2002-2014, International Business Machines
6 * Corporation and others. All Rights Reserved.
7 **********************************************************************
8 */
9 #ifndef USETITER_H
10 #define USETITER_H
11
12 #include "unicode/utypes.h"
13
14 #if U_SHOW_CPLUSPLUS_API
15
16 #include "unicode/uobject.h"
17 #include "unicode/unistr.h"
18
19 /**
20 * \file
21 * \brief C++ API: UnicodeSetIterator iterates over the contents of a UnicodeSet.
22 */
23
24 U_NAMESPACE_BEGIN
25
26 class UnicodeSet;
27 class UnicodeString;
28
29 /**
30 *
31 * UnicodeSetIterator iterates over the contents of a UnicodeSet. It
32 * iterates over either code points or code point ranges. After all
33 * code points or ranges have been returned, it returns the
34 * multicharacter strings of the UnicodeSet, if any.
35 *
36 * This class is not intended for public subclassing.
37 *
38 * <p>To iterate over code points and strings, use a loop like this:
39 * <pre>
40 * UnicodeSetIterator it(set);
41 * while (it.next()) {
42 * processItem(it.getString());
43 * }
44 * </pre>
45 * <p>Each item in the set is accessed as a string. Set elements
46 * consisting of single code points are returned as strings containing
47 * just the one code point.
48 *
49 * <p>To iterate over code point ranges, instead of individual code points,
50 * use a loop like this:
51 * <pre>
52 * UnicodeSetIterator it(set);
53 * while (it.nextRange()) {
54 * if (it.isString()) {
55 * processString(it.getString());
56 * } else {
57 * processCodepointRange(it.getCodepoint(), it.getCodepointEnd());
58 * }
59 * }
60 * </pre>
61 *
62 * To iterate over only the strings, start with <code>skipToStrings()</code>.
63 *
64 * @author M. Davis
65 * @stable ICU 2.4
66 */
67 class U_COMMON_API UnicodeSetIterator final : public UObject {
68 /**
69 * Value of <tt>codepoint</tt> if the iterator points to a string.
70 * If <tt>codepoint == IS_STRING</tt>, then examine
71 * <tt>string</tt> for the current iteration result.
72 */
73 enum { IS_STRING = -1 };
74
75 /**
76 * Current code point, or the special value <tt>IS_STRING</tt>, if
77 * the iterator points to a string.
78 */
79 UChar32 codepoint;
80
81 /**
82 * When iterating over ranges using <tt>nextRange()</tt>,
83 * <tt>codepointEnd</tt> contains the inclusive end of the
84 * iteration range, if <tt>codepoint != IS_STRING</tt>. If
85 * iterating over code points using <tt>next()</tt>, or if
86 * <tt>codepoint == IS_STRING</tt>, then the value of
87 * <tt>codepointEnd</tt> is undefined.
88 */
89 UChar32 codepointEnd;
90
91 /**
92 * If <tt>codepoint == IS_STRING</tt>, then <tt>string</tt> points
93 * to the current string. If <tt>codepoint != IS_STRING</tt>, the
94 * value of <tt>string</tt> is undefined.
95 */
96 const UnicodeString* string;
97
98 public:
99
100 /**
101 * Create an iterator over the given set. The iterator is valid
102 * only so long as <tt>set</tt> is valid.
103 * @param set set to iterate over
104 * @stable ICU 2.4
105 */
106 UnicodeSetIterator(const UnicodeSet& set);
107
108 /**
109 * Create an iterator over nothing. <tt>next()</tt> and
110 * <tt>nextRange()</tt> return false. This is a convenience
111 * constructor allowing the target to be set later.
112 * @stable ICU 2.4
113 */
114 UnicodeSetIterator();
115
116 /**
117 * Destructor.
118 * @stable ICU 2.4
119 */
120 virtual ~UnicodeSetIterator();
121
122 /**
123 * Returns true if the current element is a string. If so, the
124 * caller can retrieve it with <tt>getString()</tt>. If this
125 * method returns false, the current element is a code point or
126 * code point range, depending on whether <tt>next()</tt> or
127 * <tt>nextRange()</tt> was called.
128 * Elements of types string and codepoint can both be retrieved
129 * with the function <tt>getString()</tt>.
130 * Elements of type codepoint can also be retrieved with
131 * <tt>getCodepoint()</tt>.
132 * For ranges, <tt>getCodepoint()</tt> returns the starting codepoint
133 * of the range, and <tt>getCodepointEnd()</tt> returns the end
134 * of the range.
135 * @stable ICU 2.4
136 */
137 inline UBool isString() const;
138
139 /**
140 * Returns the current code point, if <tt>isString()</tt> returned
141 * false. Otherwise returns an undefined result.
142 * @stable ICU 2.4
143 */
144 inline UChar32 getCodepoint() const;
145
146 /**
147 * Returns the end of the current code point range, if
148 * <tt>isString()</tt> returned false and <tt>nextRange()</tt> was
149 * called. Otherwise returns an undefined result.
150 * @stable ICU 2.4
151 */
152 inline UChar32 getCodepointEnd() const;
153
154 /**
155 * Returns the current string, if <tt>isString()</tt> returned
156 * true. If the current iteration item is a code point, a UnicodeString
157 * containing that single code point is returned.
158 *
159 * Ownership of the returned string remains with the iterator.
160 * The string is guaranteed to remain valid only until the iterator is
161 * advanced to the next item, or until the iterator is deleted.
162 *
163 * @stable ICU 2.4
164 */
165 const UnicodeString& getString();
166
167 /**
168 * Skips over the remaining code points/ranges, if any.
169 * A following call to next() or nextRange() will yield a string, if there is one.
170 * No-op if next() would return false, or if it would yield a string anyway.
171 *
172 * @return *this
173 * @stable ICU 70
174 * @see UnicodeSet#strings()
175 */
skipToStrings()176 inline UnicodeSetIterator &skipToStrings() {
177 // Finish code point/range iteration.
178 range = endRange;
179 endElement = -1;
180 nextElement = 0;
181 return *this;
182 }
183
184 /**
185 * Advances the iteration position to the next element in the set,
186 * which can be either a single code point or a string.
187 * If there are no more elements in the set, return false.
188 *
189 * <p>
190 * If <tt>isString() == true</tt>, the value is a
191 * string, otherwise the value is a
192 * single code point. Elements of either type can be retrieved
193 * with the function <tt>getString()</tt>, while elements of
194 * consisting of a single code point can be retrieved with
195 * <tt>getCodepoint()</tt>
196 *
197 * <p>The order of iteration is all code points in sorted order,
198 * followed by all strings sorted order. Do not mix
199 * calls to <tt>next()</tt> and <tt>nextRange()</tt> without
200 * calling <tt>reset()</tt> between them. The results of doing so
201 * are undefined.
202 *
203 * @return true if there was another element in the set.
204 * @stable ICU 2.4
205 */
206 UBool next();
207
208 /**
209 * Returns the next element in the set, either a code point range
210 * or a string. If there are no more elements in the set, return
211 * false. If <tt>isString() == true</tt>, the value is a
212 * string and can be accessed with <tt>getString()</tt>. Otherwise the value is a
213 * range of one or more code points from <tt>getCodepoint()</tt> to
214 * <tt>getCodepointeEnd()</tt> inclusive.
215 *
216 * <p>The order of iteration is all code points ranges in sorted
217 * order, followed by all strings sorted order. Ranges are
218 * disjoint and non-contiguous. The value returned from <tt>getString()</tt>
219 * is undefined unless <tt>isString() == true</tt>. Do not mix calls to
220 * <tt>next()</tt> and <tt>nextRange()</tt> without calling
221 * <tt>reset()</tt> between them. The results of doing so are
222 * undefined.
223 *
224 * @return true if there was another element in the set.
225 * @stable ICU 2.4
226 */
227 UBool nextRange();
228
229 /**
230 * Sets this iterator to visit the elements of the given set and
231 * resets it to the start of that set. The iterator is valid only
232 * so long as <tt>set</tt> is valid.
233 * @param set the set to iterate over.
234 * @stable ICU 2.4
235 */
236 void reset(const UnicodeSet& set);
237
238 /**
239 * Resets this iterator to the start of the set.
240 * @stable ICU 2.4
241 */
242 void reset();
243
244 /**
245 * ICU "poor man's RTTI", returns a UClassID for this class.
246 *
247 * @stable ICU 2.4
248 */
249 static UClassID U_EXPORT2 getStaticClassID();
250
251 /**
252 * ICU "poor man's RTTI", returns a UClassID for the actual class.
253 *
254 * @stable ICU 2.4
255 */
256 virtual UClassID getDynamicClassID() const override;
257
258 // ======================= PRIVATES ===========================
259
260 private:
261
262 // endElement and nextElements are really UChar32's, but we keep
263 // them as signed int32_t's so we can do comparisons with
264 // endElement set to -1. Leave them as int32_t's.
265 /** The set
266 */
267 const UnicodeSet* set;
268 /** End range
269 */
270 int32_t endRange;
271 /** Range
272 */
273 int32_t range;
274 /** End element
275 */
276 int32_t endElement;
277 /** Next element
278 */
279 int32_t nextElement;
280 /** Next string
281 */
282 int32_t nextString;
283 /** String count
284 */
285 int32_t stringCount;
286
287 /**
288 * Points to the string to use when the caller asks for a
289 * string and the current iteration item is a code point, not a string.
290 */
291 UnicodeString *cpString;
292
293 /** Copy constructor. Disallowed.
294 */
295 UnicodeSetIterator(const UnicodeSetIterator&) = delete;
296
297 /** Assignment operator. Disallowed.
298 */
299 UnicodeSetIterator& operator=(const UnicodeSetIterator&) = delete;
300
301 /** Load range
302 */
303 void loadRange(int32_t range);
304 };
305
isString()306 inline UBool UnicodeSetIterator::isString() const {
307 return codepoint < 0;
308 }
309
getCodepoint()310 inline UChar32 UnicodeSetIterator::getCodepoint() const {
311 return codepoint;
312 }
313
getCodepointEnd()314 inline UChar32 UnicodeSetIterator::getCodepointEnd() const {
315 return codepointEnd;
316 }
317
318
319 U_NAMESPACE_END
320
321 #endif /* U_SHOW_CPLUSPLUS_API */
322
323 #endif
324