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#ifndef SIMDUTF_VALID_UTF16_TO_UTF32_H
#define SIMDUTF_VALID_UTF16_TO_UTF32_H
namespace simdutf {
namespace scalar {
namespace {
namespace utf16_to_utf32 {
template <endianness big_endian>
inline size_t convert_valid(const char16_t *buf, size_t len,
char32_t *utf32_output) {
const uint16_t *data = reinterpret_cast<const uint16_t *>(buf);
size_t pos = 0;
char32_t *start{utf32_output};
while (pos < len) {
uint16_t word =
!match_system(big_endian) ? utf16::swap_bytes(data[pos]) : data[pos];
if ((word & 0xF800) != 0xD800) {
// No surrogate pair, extend 16-bit word to 32-bit word
*utf32_output++ = char32_t(word);
pos++;
} else {
// must be a surrogate pair
uint16_t diff = uint16_t(word - 0xD800);
if (pos + 1 >= len) {
return 0;
} // minimal bound checking
uint16_t next_word = !match_system(big_endian)
? utf16::swap_bytes(data[pos + 1])
: data[pos + 1];
uint16_t diff2 = uint16_t(next_word - 0xDC00);
uint32_t value = (diff << 10) + diff2 + 0x10000;
*utf32_output++ = char32_t(value);
pos += 2;
}
}
return utf32_output - start;
}
} // namespace utf16_to_utf32
} // unnamed namespace
} // namespace scalar
} // namespace simdutf
#endif
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