static VALUE
rb_str_chomp_bang(int argc, VALUE *argv, VALUE str)
{
rb_encoding *enc;
VALUE rs;
int newline;
char *p, *pp, *e;
long len, rslen;
str_modify_keep_cr(str);
len = RSTRING_LEN(str);
if (len == 0) return Qnil;
p = RSTRING_PTR(str);
e = p + len;
if (argc == 0) {
rs = rb_rs;
if (rs == rb_default_rs) {
smart_chomp:
enc = rb_enc_get(str);
if (rb_enc_mbminlen(enc) > 1) {
pp = rb_enc_left_char_head(p, e-rb_enc_mbminlen(enc), e, enc);
if (rb_enc_is_newline(pp, e, enc)) {
e = pp;
}
pp = e - rb_enc_mbminlen(enc);
if (pp >= p) {
pp = rb_enc_left_char_head(p, pp, e, enc);
if (rb_enc_ascget(pp, e, 0, enc) == '\r') {
e = pp;
}
}
if (e == RSTRING_END(str)) {
return Qnil;
}
len = e - RSTRING_PTR(str);
STR_SET_LEN(str, len);
}
else {
if (RSTRING_PTR(str)[len-1] == '\n') {
STR_DEC_LEN(str);
if (RSTRING_LEN(str) > 0 &&
RSTRING_PTR(str)[RSTRING_LEN(str)-1] == '\r') {
STR_DEC_LEN(str);
}
}
else if (RSTRING_PTR(str)[len-1] == '\r') {
STR_DEC_LEN(str);
}
else {
return Qnil;
}
}
RSTRING_PTR(str)[RSTRING_LEN(str)] = '\0';
return str;
}
}
else {
rb_scan_args(argc, argv, "01", &rs);
}
if (NIL_P(rs)) return Qnil;
StringValue(rs);
rslen = RSTRING_LEN(rs);
if (rslen == 0) {
while (len>0 && p[len-1] == '\n') {
len--;
if (len>0 && p[len-1] == '\r')
len--;
}
if (len < RSTRING_LEN(str)) {
STR_SET_LEN(str, len);
RSTRING_PTR(str)[len] = '\0';
return str;
}
return Qnil;
}
if (rslen > len) return Qnil;
newline = RSTRING_PTR(rs)[rslen-1];
if (rslen == 1 && newline == '\n')
goto smart_chomp;
enc = rb_enc_check(str, rs);
if (is_broken_string(rs)) {
return Qnil;
}
pp = e - rslen;
if (p[len-1] == newline &&
(rslen <= 1 ||
memcmp(RSTRING_PTR(rs), pp, rslen) == 0)) {
if (rb_enc_left_char_head(p, pp, e, enc) != pp)
return Qnil;
if (ENC_CODERANGE(str) != ENC_CODERANGE_7BIT) {
ENC_CODERANGE_CLEAR(str);
}
STR_SET_LEN(str, RSTRING_LEN(str) - rslen);
RSTRING_PTR(str)[RSTRING_LEN(str)] = '\0';
return str;
}
return Qnil;
}