/* Provenance: openssl/openssl ia5ncasecmp (fixed).
 * repo: openssl/openssl
 * commit: d2015a783e64613d8e4a142fa05048d1863df944
 * parent: 918430ba80d94ec8f05383b43b1872b1ebb13e1a
 * commit_url: https://github.com/openssl/openssl/commit/d2015a783e64613d8e4a142fa05048d1863df944
 * cve: CVE-2021-3712
 * license: OpenSSL License
 * function: ia5ncasecmp
 * relpath: crypto/x509/v3_ncons.c
 */

static int ia5ncasecmp(const char *s1, const char *s2, size_t n)
{
    for (; n > 0; n--, s1++, s2++) {
        if (*s1 != *s2) {
            unsigned char c1 = (unsigned char)*s1, c2 = (unsigned char)*s2;

            /* Convert to lower case */
            if (c1 >= 0x41 /* A */ && c1 <= 0x5A /* Z */)
                c1 += 0x20;
            if (c2 >= 0x41 /* A */ && c2 <= 0x5A /* Z */)
                c2 += 0x20;

            if (c1 == c2)
                continue;

            if (c1 < c2)
                return -1;

            /* c1 > c2 */
            return 1;
        }
    }

    return 0;
}