ext/scintilla/src/UniConversion.h

   1 // Scintilla source code edit control
   2 /** @file UniConversion.h
   3  ** Functions to handle UTF-8 and UTF-16 strings.
   4  **/
   5 // Copyright 1998-2001 by Neil Hodgson <neilh@scintilla.org>
   6 // The License.txt file describes the conditions under which this software may be distributed.
   7
   8 #ifndef UNICONVERSION_H
   9 #define UNICONVERSION_H
  10
  11 namespace Scintilla::Internal {
  12
  13 constexpr int UTF8MaxBytes = 4;
  14
  15 constexpr int unicodeReplacementChar = 0xFFFD;
  16
  17 size_t UTF8Length(std::wstring_view wsv) noexcept;
  18 size_t UTF8PositionFromUTF16Position(std::string_view u8Text, size_t positionUTF16) noexcept;
  19 void UTF8FromUTF16(std::wstring_view wsv, char *putf, size_t len) noexcept;
  20 void UTF8FromUTF32Character(int uch, char *putf) noexcept;
  21 size_t UTF16Length(std::string_view svu8) noexcept;
  22 size_t UTF16FromUTF8(std::string_view svu8, wchar_t *tbuf, size_t tlen);
  23 size_t UTF32Length(std::string_view svu8) noexcept;
  24 size_t UTF32FromUTF8(std::string_view svu8, unsigned int *tbuf, size_t tlen);
  25 // WStringFromUTF8 does the right thing when wchar_t is 2 or 4 bytes so
  26 // works on both Windows and Unix.
  27 std::wstring WStringFromUTF8(std::string_view svu8);
  28 unsigned int UTF16FromUTF32Character(unsigned int val, wchar_t *tbuf) noexcept;
  29 bool UTF8IsValid(std::string_view svu8) noexcept;
  30 std::string FixInvalidUTF8(const std::string &text);
  31
  32 extern const unsigned char UTF8BytesOfLead[256];
  33
  34 inline int UnicodeFromUTF8(const unsigned char *us) noexcept {
  35         switch (UTF8BytesOfLead[us[0]]) {
  36         case 1:
  37                 return us[0];
  38         case 2:
  39                 return ((us[0] & 0x1F) << 6) + (us[1] & 0x3F);
  40         case 3:
  41                 return ((us[0] & 0xF) << 12) + ((us[1] & 0x3F) << 6) + (us[2] & 0x3F);
  42         default:
  43                 return ((us[0] & 0x7) << 18) + ((us[1] & 0x3F) << 12) + ((us[2] & 0x3F) << 6) + (us[3] & 0x3F);
  44         }
  45 }
  46
  47 inline constexpr bool UTF8IsTrailByte(unsigned char ch) noexcept {
  48         return (ch >= 0x80) && (ch < 0xc0);
  49 }
  50
  51 inline constexpr bool UTF8IsAscii(unsigned char ch) noexcept {
  52         return ch < 0x80;
  53 }
  54
  55 inline constexpr bool UTF8IsAscii(char ch) noexcept {
  56         const unsigned char uch = ch;
  57         return uch < 0x80;
  58 }
  59
  60 enum { UTF8MaskWidth=0x7, UTF8MaskInvalid=0x8 };
  61 int UTF8Classify(const unsigned char *us, size_t len) noexcept;
  62 inline int UTF8Classify(std::string_view sv) noexcept {
  63         return UTF8Classify(reinterpret_cast<const unsigned char *>(sv.data()), sv.length());
  64 }
  65
  66 // Similar to UTF8Classify but returns a length of 1 for invalid bytes
  67 // instead of setting the invalid flag
  68 int UTF8DrawBytes(const unsigned char *us, int len) noexcept;
  69
  70 // Line separator is U+2028 \xe2\x80\xa8
  71 // Paragraph separator is U+2029 \xe2\x80\xa9
  72 constexpr int UTF8SeparatorLength = 3;
  73 inline bool UTF8IsSeparator(const unsigned char *us) noexcept {
  74         return (us[0] == 0xe2) && (us[1] == 0x80) && ((us[2] == 0xa8) || (us[2] == 0xa9));
  75 }
  76
  77 // NEL is U+0085 \xc2\x85
  78 constexpr int UTF8NELLength = 2;
  79 inline bool UTF8IsNEL(const unsigned char *us) noexcept {
  80         return (us[0] == 0xc2) && (us[1] == 0x85);
  81 }
  82
  83 // Is the sequence of 3 char a UTF-8 line end? Only the last two char are tested for a NEL.
  84 constexpr bool UTF8IsMultibyteLineEnd(unsigned char ch0, unsigned char ch1, unsigned char ch2) noexcept {
  85         return
  86                 ((ch0 == 0xe2) && (ch1 == 0x80) && ((ch2 == 0xa8) || (ch2 == 0xa9))) ||
  87                 ((ch1 == 0xc2) && (ch2 == 0x85));
  88 }
  89
  90 enum { SURROGATE_LEAD_FIRST = 0xD800 };
  91 enum { SURROGATE_LEAD_LAST = 0xDBFF };
  92 enum { SURROGATE_TRAIL_FIRST = 0xDC00 };
  93 enum { SURROGATE_TRAIL_LAST = 0xDFFF };
  94 enum { SUPPLEMENTAL_PLANE_FIRST = 0x10000 };
  95
  96 inline constexpr unsigned int UTF16CharLength(wchar_t uch) noexcept {
  97         return ((uch >= SURROGATE_LEAD_FIRST) && (uch <= SURROGATE_LEAD_LAST)) ? 2 : 1;
  98 }
  99
 100 inline constexpr unsigned int UTF16LengthFromUTF8ByteCount(unsigned int byteCount) noexcept {
 101         return (byteCount < 4) ? 1 : 2;
 102 }
 103
 104 }
 105
 106 #endif