utf16_to_latin1.h

#include "helpers.h"

template <endianness big_endian>
inline size_t utf16_to_latin(const char16_t* buf, size_t len, char* latin_output) {
 
 const uint16_t *data = reinterpret_cast<const uint16_t *>(buf);
  size_t pos = 0;
  char* start{latin_output};
  
  while (pos < len) {
    //uint16_t word = !match_system(big_endian) ? utf16::swap_bytes(data[pos]) : data[pos]; --original
        uint16_t word = !match_system(big_endian) ? swap_bytes(data[pos]) : data[pos];
        if((word &0xF800 ) != 0xD800) { //check if the first top five bits
        // No surrogate pair, we just need to make sure that it will fit into 8 bit:
            if((word & 0xFF00) == 0) {
                *latin_output++ = char(word);
            }
            else {
                return 0;
            }
        pos++;
    } else {
      return 0; 
    }
  }
  return latin_output - start;
}

template <endianness output_endianess>
inline size_t latin_to_utf16(const char* buf, size_t len, char16_t* utf16_output) {
    const uint8_t* data = reinterpret_cast<const uint8_t*>(buf);
    size_t pos = 0;
    char16_t* start{ utf16_output };


    while (pos < len) {
        uint16_t word = uint16_t(data[pos]); // extend Latin-1 char to 16-bit Unicode code point
        if (word > 0xFF){return 0;};

        *utf16_output++ = match_system(output_endianess) ? word : swap_bytes(word);
        pos++;
    }

    return utf16_output - start;
}