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// © 2018 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html
#include "unicode/utypes.h"
#if !UCONFIG_NO_FORMATTING
#ifndef __NUMPARSE_STRINGSEGMENT_H__
#define __NUMPARSE_STRINGSEGMENT_H__
#include "unicode/unistr.h"
#include "unicode/uniset.h"
U_NAMESPACE_BEGIN
/**
* A mutable UnicodeString wrapper with a variable offset and length and
* support for case folding. The charAt, length, and subSequence methods all
* operate relative to the fixed offset into the UnicodeString.
*
* Intended to be useful for parsing.
*
* CAUTION: Since this class is mutable, it must not be used anywhere that an
* immutable object is required, like in a cache or as the key of a hash map.
*
* @author sffc (Shane Carr)
*/
// Exported as U_I18N_API for tests
class U_I18N_API StringSegment : public UMemory {
public:
StringSegment(const UnicodeString& str, bool ignoreCase);
int32_t getOffset() const;
void setOffset(int32_t start);
/**
* Equivalent to <code>setOffset(getOffset()+delta)</code>.
*
* <p>
* This method is usually called by a Matcher to register that a char was consumed. If the char is
* strong (it usually is, except for things like whitespace), follow this with a call to
* {@link ParsedNumber#setCharsConsumed}. For more information on strong chars, see that method.
*/
void adjustOffset(int32_t delta);
/**
* Adjusts the offset by the width of the current code point, either 1 or 2 chars.
*/
void adjustOffsetByCodePoint();
void setLength(int32_t length);
void resetLength();
int32_t length() const;
char16_t charAt(int32_t index) const;
UChar32 codePointAt(int32_t index) const;
UnicodeString toUnicodeString() const;
const UnicodeString toTempUnicodeString() const;
/**
* Returns the first code point in the string segment, or -1 if the string starts with an invalid
* code point.
*
* <p>
* <strong>Important:</strong> Most of the time, you should use {@link #startsWith}, which handles case
* folding logic, instead of this method.
*/
UChar32 getCodePoint() const;
/**
* Returns true if the first code point of this StringSegment equals the given code point.
*
* <p>
* This method will perform case folding if case folding is enabled for the parser.
*/
bool startsWith(UChar32 otherCp) const;
/**
* Returns true if the first code point of this StringSegment is in the given UnicodeSet.
*/
bool startsWith(const UnicodeSet& uniset) const;
/**
* Returns true if there is at least one code point of overlap between this StringSegment and the
* given UnicodeString.
*/
bool startsWith(const UnicodeString& other) const;
/**
* Returns the length of the prefix shared by this StringSegment and the given UnicodeString. For
* example, if this string segment is "aab", and the char sequence is "aac", this method returns 2,
* since the first 2 characters are the same.
*
* <p>
* This method only returns offsets along code point boundaries.
*
* <p>
* This method will perform case folding if case folding was enabled in the constructor.
*
* <p>
* IMPORTANT: The given UnicodeString must not be empty! It is the caller's responsibility to check.
*/
int32_t getCommonPrefixLength(const UnicodeString& other);
/**
* Like {@link #getCommonPrefixLength}, but never performs case folding, even if case folding is
* enabled for the parser.
*/
int32_t getCaseSensitivePrefixLength(const UnicodeString& other);
bool operator==(const UnicodeString& other) const;
private:
const UnicodeString& fStr;
int32_t fStart;
int32_t fEnd;
bool fFoldCase;
int32_t getPrefixLengthInternal(const UnicodeString& other, bool foldCase);
static bool codePointsEqual(UChar32 cp1, UChar32 cp2, bool foldCase);
};
U_NAMESPACE_END
#endif //__NUMPARSE_STRINGSEGMENT_H__
#endif /* #if !UCONFIG_NO_FORMATTING */