/* Provenance: openssl/openssl buf2hexstr_sep (fixed).
 * repo: openssl/openssl
 * commit: a91e537d16d74050dbde50bb0dfb1fe9930f0521
 * parent: b7ae7a093997b5cd549bc21cccd715510fef86c0
 * commit_url: https://github.com/openssl/openssl/commit/a91e537d16d74050dbde50bb0dfb1fe9930f0521
 * cve: CVE-2026-31789
 * license: Apache-2.0
 * function: buf2hexstr_sep
 * relpath: crypto/o_str.c
 */

static int buf2hexstr_sep(char *str, size_t str_n, size_t *strlength,
    const unsigned char *buf, size_t buflen,
    const char sep)
{
    static const char hexdig[] = "0123456789ABCDEF";
    const unsigned char *p;
    char *q;
    size_t i;
    int has_sep = (sep != CH_ZERO);
    size_t len = has_sep ? buflen * 3 : 1 + buflen * 2;

    if (buflen > (has_sep ? SIZE_MAX / 3 : (SIZE_MAX - 1) / 2)) {
        ERR_raise(ERR_LIB_CRYPTO, CRYPTO_R_TOO_MANY_BYTES);
        return 0;
    }

    if (len == 0)
        ++len;
    if (strlength != NULL)
        *strlength = len;
    if (str == NULL)
        return 1;

    if (str_n < len) {
        ERR_raise(ERR_LIB_CRYPTO, CRYPTO_R_TOO_SMALL_BUFFER);
        return 0;
    }

    q = str;
    for (i = 0, p = buf; i < buflen; i++, p++) {
        *q++ = hexdig[(*p >> 4) & 0xf];
        *q++ = hexdig[*p & 0xf];
        if (has_sep)
            *q++ = sep;
    }
    if (has_sep && buflen > 0)
        --q;
    *q = CH_ZERO;

#ifdef CHARSET_EBCDIC
    ebcdic2ascii(str, str, q - str);
#endif
    return 1;
}