utf8_constexpr14_impl int utf8ncasecmp()

in src/common/utils/Utf8.h [513:583]

• 51 lines of code
• 19 McCabe index (conditional complexity)

utf8_constexpr14_impl int utf8ncasecmp(const utf8_int8_t *src1, const utf8_int8_t *src2, size_t n) {
  utf8_int32_t src1_lwr_cp = 0, src2_lwr_cp = 0, src1_upr_cp = 0, src2_upr_cp = 0, src1_orig_cp = 0, src2_orig_cp = 0;

  do {
    const utf8_int8_t *const s1 = src1;
    const utf8_int8_t *const s2 = src2;

    /* first check that we have enough bytes left in n to contain an entire
     * codepoint */
    if (0 == n) {
      return 0;
    }

    if ((1 == n) && ((0xc0 == (0xe0 & *s1)) || (0xc0 == (0xe0 & *s2)))) {
      const utf8_int32_t c1 = (0xe0 & *s1);
      const utf8_int32_t c2 = (0xe0 & *s2);

      if (c1 < c2) {
        return c1 - c2;
      } else {
        return 0;
      }
    }

    if ((2 >= n) && ((0xe0 == (0xf0 & *s1)) || (0xe0 == (0xf0 & *s2)))) {
      const utf8_int32_t c1 = (0xf0 & *s1);
      const utf8_int32_t c2 = (0xf0 & *s2);

      if (c1 < c2) {
        return c1 - c2;
      } else {
        return 0;
      }
    }

    if ((3 >= n) && ((0xf0 == (0xf8 & *s1)) || (0xf0 == (0xf8 & *s2)))) {
      const utf8_int32_t c1 = (0xf8 & *s1);
      const utf8_int32_t c2 = (0xf8 & *s2);

      if (c1 < c2) {
        return c1 - c2;
      } else {
        return 0;
      }
    }

    src1 = utf8codepoint(src1, &src1_orig_cp);
    src2 = utf8codepoint(src2, &src2_orig_cp);
    n -= utf8codepointsize(src1_orig_cp);

    src1_lwr_cp = utf8lwrcodepoint(src1_orig_cp);
    src2_lwr_cp = utf8lwrcodepoint(src2_orig_cp);

    src1_upr_cp = utf8uprcodepoint(src1_orig_cp);
    src2_upr_cp = utf8uprcodepoint(src2_orig_cp);

    /* check if the lowered codepoints match */
    if ((0 == src1_orig_cp) && (0 == src2_orig_cp)) {
      return 0;
    } else if ((src1_lwr_cp == src2_lwr_cp) || (src1_upr_cp == src2_upr_cp)) {
      continue;
    }

    /* if they don't match, then we return the difference between the characters
     */
    return src1_lwr_cp - src2_lwr_cp;
  } while (0 < n);

  /* both utf8 strings matched */
  return 0;
}