+/* --- Threads and multiplicity -------------------------------------------- */
+
+#ifndef NOOP
+# define NOOP
+#endif
+
+#ifndef dNOOP
+# define dNOOP
+#endif
+
+#ifndef SU_MULTIPLICITY
+# if defined(MULTIPLICITY) || defined(PERL_IMPLICIT_CONTEXT)
+# define SU_MULTIPLICITY 1
+# else
+# define SU_MULTIPLICITY 0
+# endif
+#endif
+#if SU_MULTIPLICITY && !defined(tTHX)
+# define tTHX PerlInterpreter*
+#endif
+
+#if SU_MULTIPLICITY && defined(USE_ITHREADS) && defined(dMY_CXT) && defined(MY_CXT) && defined(START_MY_CXT) && defined(MY_CXT_INIT) && (defined(MY_CXT_CLONE) || defined(dMY_CXT_SV))
+# define SU_THREADSAFE 1
+# ifndef MY_CXT_CLONE
+# define MY_CXT_CLONE \
+ dMY_CXT_SV; \
+ my_cxt_t *my_cxtp = (my_cxt_t*)SvPVX(newSV(sizeof(my_cxt_t)-1)); \
+ Copy(INT2PTR(my_cxt_t*, SvUV(my_cxt_sv)), my_cxtp, 1, my_cxt_t); \
+ sv_setuv(my_cxt_sv, PTR2UV(my_cxtp))
+# endif
+#else
+# define SU_THREADSAFE 0
+# undef dMY_CXT
+# define dMY_CXT dNOOP
+# undef MY_CXT
+# define MY_CXT su_globaldata
+# undef START_MY_CXT
+# define START_MY_CXT STATIC my_cxt_t MY_CXT;
+# undef MY_CXT_INIT
+# define MY_CXT_INIT NOOP
+# undef MY_CXT_CLONE
+# define MY_CXT_CLONE NOOP
+#endif
+
+/* --- Stack manipulations ------------------------------------------------- */
+
+#ifndef SvCANEXISTDELETE
+# define SvCANEXISTDELETE(sv) \
+ (!SvRMAGICAL(sv) \
+ || ((mg = mg_find((SV *) sv, PERL_MAGIC_tied)) \
+ && (stash = SvSTASH(SvRV(SvTIED_obj((SV *) sv, mg)))) \
+ && gv_fetchmethod_autoload(stash, "EXISTS", TRUE) \
+ && gv_fetchmethod_autoload(stash, "DELETE", TRUE) \
+ ) \
+ )
+#endif
+
+/* ... Saving array elements ............................................... */
+
+STATIC I32 su_av_key2idx(pTHX_ AV *av, I32 key) {
+#define su_av_key2idx(A, K) su_av_key2idx(aTHX_ (A), (K))
+ I32 idx;
+
+ if (key >= 0)
+ return key;
+
+/* Added by MJD in perl-5.8.1 with 6f12eb6d2a1dfaf441504d869b27d2e40ef4966a */
+#if SU_HAS_PERL(5, 8, 1)
+ if (SvRMAGICAL(av)) {
+ const MAGIC * const tied_magic = mg_find((SV *) av, PERL_MAGIC_tied);
+ if (tied_magic) {
+ SV * const * const negative_indices_glob =
+ hv_fetch(SvSTASH(SvRV(SvTIED_obj((SV *) (av), tied_magic))),
+ NEGATIVE_INDICES_VAR, 16, 0);
+ if (negative_indices_glob && SvTRUE(GvSV(*negative_indices_glob)))
+ return key;
+ }
+ }
+#endif
+
+ idx = key + av_len(av) + 1;
+ if (idx < 0)
+ return key;
+
+ return idx;
+}
+
+#ifndef SAVEADELETE
+
+typedef struct {
+ AV *av;
+ I32 idx;
+} su_ud_adelete;
+
+STATIC void su_adelete(pTHX_ void *ud_) {
+ su_ud_adelete *ud = (su_ud_adelete *) ud_;
+
+ av_delete(ud->av, ud->idx, G_DISCARD);
+ SvREFCNT_dec(ud->av);
+
+ Safefree(ud);
+}
+
+STATIC void su_save_adelete(pTHX_ AV *av, I32 idx) {
+#define su_save_adelete(A, K) su_save_adelete(aTHX_ (A), (K))
+ su_ud_adelete *ud;
+
+ Newx(ud, 1, su_ud_adelete);
+ ud->av = av;
+ ud->idx = idx;
+ SvREFCNT_inc(av);
+
+ SAVEDESTRUCTOR_X(su_adelete, ud);
+}
+
+#define SAVEADELETE(A, K) su_save_adelete((A), (K))
+
+#endif /* SAVEADELETE */
+
+STATIC void su_save_aelem(pTHX_ AV *av, SV *key, SV *val) {
+#define su_save_aelem(A, K, V) su_save_aelem(aTHX_ (A), (K), (V))
+ I32 idx;
+ I32 preeminent = 1;
+ SV **svp;
+ HV *stash;
+ MAGIC *mg;
+
+ idx = su_av_key2idx(av, SvIV(key));
+
+ if (SvCANEXISTDELETE(av))
+ preeminent = av_exists(av, idx);
+
+ svp = av_fetch(av, idx, 1);
+ if (!svp || *svp == &PL_sv_undef) croak(PL_no_aelem, idx);
+
+ if (preeminent)
+ save_aelem(av, idx, svp);
+ else
+ SAVEADELETE(av, idx);
+
+ if (val) { /* local $x[$idx] = $val; */
+ SvSetMagicSV(*svp, val);
+ } else { /* local $x[$idx]; delete $x[$idx]; */
+ av_delete(av, idx, G_DISCARD);
+ }
+}
+
+/* ... Saving hash elements ................................................ */
+
+STATIC void su_save_helem(pTHX_ HV *hv, SV *keysv, SV *val) {
+#define su_save_helem(H, K, V) su_save_helem(aTHX_ (H), (K), (V))
+ I32 preeminent = 1;
+ HE *he;
+ SV **svp;
+ HV *stash;
+ MAGIC *mg;
+
+ if (SvCANEXISTDELETE(hv) || mg_find((SV *) hv, PERL_MAGIC_env))
+ preeminent = hv_exists_ent(hv, keysv, 0);
+
+ he = hv_fetch_ent(hv, keysv, 1, 0);
+ svp = he ? &HeVAL(he) : NULL;
+ if (!svp || *svp == &PL_sv_undef) croak("Modification of non-creatable hash value attempted, subscript \"%s\"", SvPV_nolen_const(*svp));
+
+ if (HvNAME_get(hv) && isGV(*svp)) {
+ save_gp((GV *) *svp, 0);
+ return;
+ }
+
+ if (preeminent)
+ save_helem(hv, keysv, svp);
+ else {
+ STRLEN keylen;
+ const char * const key = SvPV_const(keysv, keylen);
+ SAVEDELETE(hv, savepvn(key, keylen),
+ SvUTF8(keysv) ? -(I32)keylen : (I32)keylen);
+ }
+
+ if (val) { /* local $x{$keysv} = $val; */
+ SvSetMagicSV(*svp, val);
+ } else { /* local $x{$keysv}; delete $x{$keysv}; */
+ (void)hv_delete_ent(hv, keysv, G_DISCARD, HeHASH(he));
+ }
+}
+
+/* --- Actions ------------------------------------------------------------- */
+