1// © 2018 and later: Unicode, Inc. and others.
2// License & terms of use: http://www.unicode.org/copyright.html
3
4#include "unicode/utypes.h"
5
6#if !UCONFIG_NO_FORMATTING
7#ifndef __NUMPARSE_STRINGSEGMENT_H__
8#define __NUMPARSE_STRINGSEGMENT_H__
9
10#include "unicode/unistr.h"
11#include "unicode/uniset.h"
12
13U_NAMESPACE_BEGIN
14
15
16/**
17 * A mutable UnicodeString wrapper with a variable offset and length and
18 * support for case folding. The charAt, length, and subSequence methods all
19 * operate relative to the fixed offset into the UnicodeString.
20 *
21 * Intended to be useful for parsing.
22 *
23 * CAUTION: Since this class is mutable, it must not be used anywhere that an
24 * immutable object is required, like in a cache or as the key of a hash map.
25 *
26 * @author sffc (Shane Carr)
27 */
28// Exported as U_I18N_API for tests
29class U_I18N_API StringSegment : public UMemory {
30 public:
31 StringSegment(const UnicodeString& str, bool ignoreCase);
32
33 int32_t getOffset() const;
34
35 void setOffset(int32_t start);
36
37 /**
38 * Equivalent to <code>setOffset(getOffset()+delta)</code>.
39 *
40 * <p>
41 * This method is usually called by a Matcher to register that a char was consumed. If the char is
42 * strong (it usually is, except for things like whitespace), follow this with a call to
43 * {@link ParsedNumber#setCharsConsumed}. For more information on strong chars, see that method.
44 */
45 void adjustOffset(int32_t delta);
46
47 /**
48 * Adjusts the offset by the width of the current code point, either 1 or 2 chars.
49 */
50 void adjustOffsetByCodePoint();
51
52 void setLength(int32_t length);
53
54 void resetLength();
55
56 int32_t length() const;
57
58 char16_t charAt(int32_t index) const;
59
60 UChar32 codePointAt(int32_t index) const;
61
62 UnicodeString toUnicodeString() const;
63
64 const UnicodeString toTempUnicodeString() const;
65
66 /**
67 * Returns the first code point in the string segment, or -1 if the string starts with an invalid
68 * code point.
69 *
70 * <p>
71 * <strong>Important:</strong> Most of the time, you should use {@link #startsWith}, which handles case
72 * folding logic, instead of this method.
73 */
74 UChar32 getCodePoint() const;
75
76 /**
77 * Returns true if the first code point of this StringSegment equals the given code point.
78 *
79 * <p>
80 * This method will perform case folding if case folding is enabled for the parser.
81 */
82 bool startsWith(UChar32 otherCp) const;
83
84 /**
85 * Returns true if the first code point of this StringSegment is in the given UnicodeSet.
86 */
87 bool startsWith(const UnicodeSet& uniset) const;
88
89 /**
90 * Returns true if there is at least one code point of overlap between this StringSegment and the
91 * given UnicodeString.
92 */
93 bool startsWith(const UnicodeString& other) const;
94
95 /**
96 * Returns the length of the prefix shared by this StringSegment and the given UnicodeString. For
97 * example, if this string segment is "aab", and the char sequence is "aac", this method returns 2,
98 * since the first 2 characters are the same.
99 *
100 * <p>
101 * This method only returns offsets along code point boundaries.
102 *
103 * <p>
104 * This method will perform case folding if case folding was enabled in the constructor.
105 *
106 * <p>
107 * IMPORTANT: The given UnicodeString must not be empty! It is the caller's responsibility to check.
108 */
109 int32_t getCommonPrefixLength(const UnicodeString& other);
110
111 /**
112 * Like {@link #getCommonPrefixLength}, but never performs case folding, even if case folding is
113 * enabled for the parser.
114 */
115 int32_t getCaseSensitivePrefixLength(const UnicodeString& other);
116
117 bool operator==(const UnicodeString& other) const;
118
119 private:
120 const UnicodeString& fStr;
121 int32_t fStart;
122 int32_t fEnd;
123 bool fFoldCase;
124
125 int32_t getPrefixLengthInternal(const UnicodeString& other, bool foldCase);
126
127 static bool codePointsEqual(UChar32 cp1, UChar32 cp2, bool foldCase);
128};
129
130
131U_NAMESPACE_END
132
133#endif //__NUMPARSE_STRINGSEGMENT_H__
134#endif /* #if !UCONFIG_NO_FORMATTING */
135