tor-browser

The Tor Browser
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string_segment.h (4110B)

      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 
     13 U_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
     29 class 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    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 
    131 U_NAMESPACE_END
    132 
    133 #endif //__NUMPARSE_STRINGSEGMENT_H__
    134 #endif /* #if !UCONFIG_NO_FORMATTING */