return;
}
+/* Work around compiler warnings about unsigned >= THRESHOLD when thres-
+ hold is 0. */
+#if SV_COW_THRESHOLD
+# define GE_COW_THRESHOLD(len) ((len) >= SV_COW_THRESHOLD)
+#else
+# define GE_COW_THRESHOLD(len) 1
+#endif
+#if SV_COWBUF_THRESHOLD
+# define GE_COWBUF_THRESHOLD(len) ((len) >= SV_COWBUF_THRESHOLD)
+#else
+# define GE_COWBUF_THRESHOLD(len) 1
+#endif
+
void
Perl_sv_setsv_flags(pTHX_ SV *dstr, SV* sstr, const I32 flags)
{
}
else if (sflags & SVp_POK) {
bool isSwipe = 0;
+ const STRLEN cur = SvCUR(sstr);
+ const STRLEN len = SvLEN(sstr);
/*
* Check to see if we can just swipe the string. If so, it's a
(((flags & SV_COW_SHARED_HASH_KEYS)
? !(sflags & SVf_IsCOW)
#ifdef PERL_NEW_COPY_ON_WRITE
+ || (len &&
+ ((!GE_COWBUF_THRESHOLD(cur) && SvLEN(dstr) > cur)
/* If this is a regular (non-hek) COW, only so many COW
"copies" are possible. */
- || (SvLEN(sstr) && CowREFCNT(sstr) == SV_COW_REFCNT_MAX)
+ || CowREFCNT(sstr) == SV_COW_REFCNT_MAX))
#endif
: 1 /* If making a COW copy is forbidden then the behaviour we
desire is as if the source SV isn't actually already
(!(flags & SV_NOSTEAL)) &&
/* and we're allowed to steal temps */
SvREFCNT(sstr) == 1 && /* and no other references to it? */
- SvLEN(sstr)) /* and really is a string */
+ len) /* and really is a string */
#ifdef PERL_ANY_COW
&& ((flags & SV_COW_SHARED_HASH_KEYS)
? (!((sflags & CAN_COW_MASK) == CAN_COW_FLAGS
&& SvTYPE(sstr) >= SVt_PVIV
# else
&& !(sflags & SVf_IsCOW)
- && SvCUR(sstr)+1 < SvLEN(sstr)
+ && GE_COW_THRESHOLD(cur) && cur+1 < len
+ && (GE_COWBUF_THRESHOLD(cur) || SvLEN(dstr) < cur+1)
# endif
))
: 1)
) {
/* Failed the swipe test, and it's not a shared hash key either.
Have to copy the string. */
- STRLEN len = SvCUR(sstr);
- SvGROW(dstr, len + 1); /* inlined from sv_setpvn */
- Move(SvPVX_const(sstr),SvPVX(dstr),len,char);
- SvCUR_set(dstr, len);
+ SvGROW(dstr, cur + 1); /* inlined from sv_setpvn */
+ Move(SvPVX_const(sstr),SvPVX(dstr),cur,char);
+ SvCUR_set(dstr, cur);
*SvEND(dstr) = '\0';
} else {
/* If PERL_OLD_COPY_ON_WRITE is not defined, then isSwipe will always
if (!isSwipe) {
/* making another shared SV. */
- STRLEN cur = SvCUR(sstr);
- STRLEN len = SvLEN(sstr);
#ifdef PERL_ANY_COW
if (len) {
# ifdef PERL_OLD_COPY_ON_WRITE
/* Note: To allow 256 COW "copies", a refcnt of 0 means 1. */
# define CowREFCNT(sv) (*(U8 *)(SvPVX(sv)+SvLEN(sv)-1))
# define SV_COW_REFCNT_MAX ((1 << sizeof(U8)*8) - 1)
+# ifndef SV_COW_THRESHOLD
+# define SV_COW_THRESHOLD 0 /* min string length for cow */
+# endif
+# ifndef SV_COWBUF_THRESHOLD
+# define SV_COWBUF_THRESHOLD 1250 /* min string length for cow */
+# endif /* over existing buffer */
# endif
#endif /* PERL_OLD_COPY_ON_WRITE */