+ SvSCREAM_on(sv);
+ if (!mg)
+ mg = sv_magicext(sv, NULL, PERL_MAGIC_study, &PL_vtbl_regexp, NULL, 0);
+ mg->mg_ptr = sfirst_raw;
+ mg->mg_len = size;
+ mg->mg_private = quanta;
+
+ memset(sfirst_raw, ~0, 256 * quanta);
+
+ /* The assumption here is that most studied strings are fairly short, hence
+ the pain of the extra code is worth it, given the memory savings.
+ 80 character string, 336 bytes as U8, down from 1344 as U32
+ 800 character string, 2112 bytes as U16, down from 4224 as U32
+ */
+
+ if (quanta == 1) {
+ U8 *const sfirst = (U8 *)sfirst_raw;
+ U8 *const snext = sfirst + 256;
+ while (len-- > 0) {
+ const U8 ch = s[len];
+ snext[len] = sfirst[ch];
+ sfirst[ch] = len;
+ }
+ } else if (quanta == 2) {
+ U16 *const sfirst = (U16 *)sfirst_raw;
+ U16 *const snext = sfirst + 256;
+ while (len-- > 0) {
+ const U8 ch = s[len];
+ snext[len] = sfirst[ch];
+ sfirst[ch] = len;
+ }
+ } else {
+ U32 *const sfirst = (U32 *)sfirst_raw;
+ U32 *const snext = sfirst + 256;
+ while (len-- > 0) {
+ const U8 ch = s[len];
+ snext[len] = sfirst[ch];
+ sfirst[ch] = len;
+ }