VALUE
rb_str_succ(VALUE orig)
{
rb_encoding *enc;
VALUE str;
char *sbeg, *s, *e, *last_alnum = 0;
int c = -1;
long l;
char carry[ONIGENC_CODE_TO_MBC_MAXLEN] = "\1";
int carry_pos = 0, carry_len = 1;
enum neighbor_char neighbor = NEIGHBOR_FOUND;
str = rb_str_new5(orig, RSTRING_PTR(orig), RSTRING_LEN(orig));
rb_enc_cr_str_copy_for_substr(str, orig);
OBJ_INFECT(str, orig);
if (RSTRING_LEN(str) == 0) return str;
enc = STR_ENC_GET(orig);
sbeg = RSTRING_PTR(str);
s = e = sbeg + RSTRING_LEN(str);
while ((s = rb_enc_prev_char(sbeg, s, e, enc)) != 0) {
if (neighbor == NEIGHBOR_NOT_CHAR && last_alnum) {
if (ISALPHA(*last_alnum) ? ISDIGIT(*s) :
ISDIGIT(*last_alnum) ? ISALPHA(*s) : 0) {
s = last_alnum;
break;
}
}
if ((l = rb_enc_precise_mbclen(s, e, enc)) <= 0) continue;
neighbor = enc_succ_alnum_char(s, l, enc, carry);
switch (neighbor) {
case NEIGHBOR_NOT_CHAR:
continue;
case NEIGHBOR_FOUND:
return str;
case NEIGHBOR_WRAPPED:
last_alnum = s;
break;
}
c = 1;
carry_pos = s - sbeg;
carry_len = l;
}
if (c == -1) { /* str contains no alnum */
s = e;
while ((s = rb_enc_prev_char(sbeg, s, e, enc)) != 0) {
enum neighbor_char neighbor;
if ((l = rb_enc_precise_mbclen(s, e, enc)) <= 0) continue;
neighbor = enc_succ_char(s, l, enc);
if (neighbor == NEIGHBOR_FOUND)
return str;
if (rb_enc_precise_mbclen(s, s+l, enc) != l) {
/* wrapped to \0...\0. search next valid char. */
enc_succ_char(s, l, enc);
}
if (!rb_enc_asciicompat(enc)) {
MEMCPY(carry, s, char, l);
carry_len = l;
}
carry_pos = s - sbeg;
}
}
RESIZE_CAPA(str, RSTRING_LEN(str) + carry_len);
s = RSTRING_PTR(str) + carry_pos;
memmove(s + carry_len, s, RSTRING_LEN(str) - carry_pos);
memmove(s, carry, carry_len);
STR_SET_LEN(str, RSTRING_LEN(str) + carry_len);
RSTRING_PTR(str)[RSTRING_LEN(str)] = '\0';
rb_enc_str_coderange(str);
return str;
}