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#include "html.h"
#include "utf8_strings.h"
namespace litehtml
{
// consume one utf-8 char and increment index accordingly
// if str[index] == 0 index is not incremented
char32_t read_utf8_char(const string& str, int& index)
{
auto getb = [&]() -> byte
{
if (!str[index]) return 0;
return str[index++];
};
byte b1 = getb();
// Determine whether we are dealing
// with a one-, two-, three-, or four-
// byte sequence.
if ((b1 & 0x80) == 0)
{
// 1-byte sequence: 000000000xxxxxxx = 0xxxxxxx
return b1;
}
else if ((b1 & 0xe0) == 0xc0)
{
// 2-byte sequence: 00000yyyyyxxxxxx = 110yyyyy 10xxxxxx
char32_t r = (b1 & 0x1f) << 6;
r |= getb() & 0x3f;
return r;
}
else if ((b1 & 0xf0) == 0xe0)
{
// 3-byte sequence: zzzzyyyyyyxxxxxx = 1110zzzz 10yyyyyy 10xxxxxx
char32_t r = (b1 & 0x0f) << 12;
r |= (getb() & 0x3f) << 6;
r |= getb() & 0x3f;
return r;
}
else if ((b1 & 0xf8) == 0xf0)
{
// 4-byte sequence: uuuzzzzzzyyyyyyxxxxxx = 11110uuu 10zzzzzz 10yyyyyy 10xxxxxx
byte b2 = getb() & 0x3f;
byte b3 = getb() & 0x3f;
byte b4 = getb() & 0x3f;
return ((b1 & 7) << 18) | (b2 << 12) | (b3 << 6) | b4;
}
return 0xFFFD;
}
// No error handling, str must be valid UTF-8 (it is ensured by document::parse_html and css_parser::parse_stylesheet).
// Currently used only in css parser, where actual char value is not needed, so it returns void.
void prev_utf8_char(const string& str, int& index)
{
while (index && ((byte)str[--index] >> 6) == 0b10); // skip continuation bytes
}
void append_char(string& str, char32_t code)
{
if (code <= 0x7F)
{
str += (char)code;
}
else if (code <= 0x7FF)
{
str += char((code >> 6) + 192);
str += (code & 63) + 128;
}
else if (0xd800 <= code && code <= 0xdfff)
{
// error: unexpected surrogate (code is UTF-32, not UTF-16)
}
else if (code <= 0xFFFF)
{
str += char((code >> 12) + 224);
str += ((code >> 6) & 63) + 128;
str += (code & 63) + 128;
}
else if (code <= 0x10FFFF)
{
str += char((code >> 18) + 240);
str += ((code >> 12) & 63) + 128;
str += ((code >> 6) & 63) + 128;
str += (code & 63) + 128;
}
}
utf8_to_utf32::utf8_to_utf32(const string& val)
{
int index = 0;
while (char32_t ch = read_utf8_char(val, index))
m_str += ch;
}
utf32_to_utf8::utf32_to_utf8(const std::u32string& val)
{
for (auto ch : val)
append_char(m_str, ch);
}
} // namespace litehtml
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