icuSources/i18n/string_segment.cpp

   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
   8 // Allow implicit conversion from char16_t* to UnicodeString for this file:
   9 // Helpful in toString methods and elsewhere.
  10 #define UNISTR_FROM_STRING_EXPLICIT
  11
  12 #include "numparse_types.h"
  13 #include "string_segment.h"
  14 #include "putilimp.h"
  15 #include "unicode/utf16.h"
  16 #include "unicode/uniset.h"
  17
  18 U_NAMESPACE_BEGIN
  19
  20
  21 StringSegment::StringSegment(const UnicodeString& str, bool ignoreCase)
  22         : fStr(str), fStart(0), fEnd(str.length()),
  23           fFoldCase(ignoreCase) {}
  24
  25 int32_t StringSegment::getOffset() const {
  26     return fStart;
  27 }
  28
  29 void StringSegment::setOffset(int32_t start) {
  30     fStart = start;
  31 }
  32
  33 void StringSegment::adjustOffset(int32_t delta) {
  34     fStart += delta;
  35 }
  36
  37 void StringSegment::adjustOffsetByCodePoint() {
  38     fStart += U16_LENGTH(getCodePoint());
  39 }
  40
  41 void StringSegment::setLength(int32_t length) {
  42     fEnd = fStart + length;
  43 }
  44
  45 void StringSegment::resetLength() {
  46     fEnd = fStr.length();
  47 }
  48
  49 int32_t StringSegment::length() const {
  50     return fEnd - fStart;
  51 }
  52
  53 char16_t StringSegment::charAt(int32_t index) const {
  54     return fStr.charAt(index + fStart);
  55 }
  56
  57 UChar32 StringSegment::codePointAt(int32_t index) const {
  58     return fStr.char32At(index + fStart);
  59 }
  60
  61 UnicodeString StringSegment::toUnicodeString() const {
  62     return UnicodeString(fStr.getBuffer() + fStart, fEnd - fStart);
  63 }
  64
  65 const UnicodeString StringSegment::toTempUnicodeString() const {
  66     // Use the readonly-aliasing constructor for efficiency.
  67     return UnicodeString(FALSE, fStr.getBuffer() + fStart, fEnd - fStart);
  68 }
  69
  70 UChar32 StringSegment::getCodePoint() const {
  71     char16_t lead = fStr.charAt(fStart);
  72     if (U16_IS_LEAD(lead) && fStart + 1 < fEnd) {
  73         return fStr.char32At(fStart);
  74     } else if (U16_IS_SURROGATE(lead)) {
  75         return -1;
  76     } else {
  77         return lead;
  78     }
  79 }
  80
  81 bool StringSegment::startsWith(UChar32 otherCp) const {
  82     return codePointsEqual(getCodePoint(), otherCp, fFoldCase);
  83 }
  84
  85 bool StringSegment::startsWith(const UnicodeSet& uniset) const {
  86     // TODO: Move UnicodeSet case-folding logic here.
  87     // TODO: Handle string matches here instead of separately.
  88     UChar32 cp = getCodePoint();
  89     if (cp == -1) {
  90         return false;
  91     }
  92     return uniset.contains(cp);
  93 }
  94
  95 bool StringSegment::startsWith(const UnicodeString& other) const {
  96     if (other.isBogus() || other.length() == 0 || length() == 0) {
  97         return false;
  98     }
  99     int cp1 = getCodePoint();
 100     int cp2 = other.char32At(0);
 101     return codePointsEqual(cp1, cp2, fFoldCase);
 102 }
 103
 104 int32_t StringSegment::getCommonPrefixLength(const UnicodeString& other) {
 105     return getPrefixLengthInternal(other, fFoldCase);
 106 }
 107
 108 int32_t StringSegment::getCaseSensitivePrefixLength(const UnicodeString& other) {
 109     return getPrefixLengthInternal(other, false);
 110 }
 111
 112 int32_t StringSegment::getPrefixLengthInternal(const UnicodeString& other, bool foldCase) {
 113     U_ASSERT(other.length() > 0);
 114     int32_t offset = 0;
 115     for (; offset < uprv_min(length(), other.length());) {
 116         // TODO: case-fold code points, not chars
 117         char16_t c1 = charAt(offset);
 118         char16_t c2 = other.charAt(offset);
 119         if (!codePointsEqual(c1, c2, foldCase)) {
 120             break;
 121         }
 122         offset++;
 123     }
 124     return offset;
 125 }
 126
 127 bool StringSegment::codePointsEqual(UChar32 cp1, UChar32 cp2, bool foldCase) {
 128     if (cp1 == cp2) {
 129         return true;
 130     }
 131     if (!foldCase) {
 132         return false;
 133     }
 134     cp1 = u_foldCase(cp1, TRUE);
 135     cp2 = u_foldCase(cp2, TRUE);
 136     return cp1 == cp2;
 137 }
 138
 139 bool StringSegment::operator==(const UnicodeString& other) const {
 140     return toTempUnicodeString() == other;
 141 }
 142
 143
 144 U_NAMESPACE_END
 145 #endif /* #if !UCONFIG_NO_FORMATTING */