+Perl_mode_from_discipline(pTHX_ SV *discp)
+{
+ int mode = O_BINARY;
+ if (discp) {
+ STRLEN len;
+ char *s = SvPV(discp,len);
+ while (*s) {
+ if (*s == ':') {
+ switch (s[1]) {
+ case 'r':
+ if (len > 3 && strnEQ(s+1, "raw", 3)
+ && (!s[4] || s[4] == ':' || isSPACE(s[4])))
+ {
+ mode = O_BINARY;
+ s += 4;
+ len -= 4;
+ break;
+ }
+ /* FALL THROUGH */
+ case 'c':
+ if (len > 4 && strnEQ(s+1, "crlf", 4)
+ && (!s[5] || s[5] == ':' || isSPACE(s[5])))
+ {
+ mode = O_TEXT;
+ s += 5;
+ len -= 5;
+ break;
+ }
+ /* FALL THROUGH */
+ default:
+ goto fail_discipline;
+ }
+ }
+ else if (isSPACE(*s)) {
+ ++s;
+ --len;
+ }
+ else {
+ char *end;
+fail_discipline:
+ end = strchr(s+1, ':');
+ if (!end)
+ end = s+len;
+ Perl_croak(aTHX_ "Unknown discipline '%.*s'", end-s, s);
+ }
+ }
+ }
+ return mode;
+}
+
+int
+Perl_do_binmode(pTHX_ PerlIO *fp, int iotype, int mode)